Thursday, November 15, 2012

Self awarenss and our "spider jar"

Margit Hesthammer writes a lovely piece for the opinionator section of the NYTimes that has me thinking "I wish I had written that." It is consonant with the same core of ideas that runs through my web lectures shown in the left column of this blog, such as the "I Illusion" and "Mindstuff - a user's guide," but presented in a much more congenial and approachable fashion. (I frequently use "pandora's box" as a metaphor similar to the "spiders in a jar" used in the essay). I strongly urge you to read the whole piece, but here I excerpt a series of clips:
...behind all the containers I pour myself into from moment to moment, is my awareness of the boundless ocean of awareness itself…an unruly sea of infinite possibility, lurking in the back room…It conjures up the image Jonathan Franzen uses in his novel "The Corrections" of an impending thunderstorm: "big spiders in a little jar." Only the jar in this case is infinitely vast, the spiders correspondingly enormous. They huddle in the back room, waiting for the lid to come off...waiting to leak or seep or sneak through some hidden cat-door and flood the room I live in…With it is the chronic background anxiety that if I don't pour myself into this or that (read my book, clean the house, or at the very least think a bunch of thoughts), I'll fall into this ocean of shapelessness and lose all sense of definition. I'll be ejected from the safe confines of my predictable foreground world, where all the familiar experiences live: the sensations and tastes and textures that confirm my sense of who I am.
…when I do stray, accidentally or intentionally, into this formless background, I recall all too quickly what the foreground commotion is doing for me….It's protecting me from the intolerable experience of being a personality: a rabid consumer of ego-supplies with a curiously cruel capacity for self-awareness. A capacity that leads perversely to the realization that despite my hard-won knowledge that all my yearnings are ultimately doomed, still there will never be an end to yearning…It's protecting me from the unbearable taste of my separateness, my chronic disconnection from life, within and without. It's creating the wall of white noise that distracts me from my deep sense of meaninglessness, my feeling of being locked in and locked out at the same time - trapped on the surface of my life, nose against the glass, dimly aware that somewhere a feast is going on. Somewhere I'm not…
At some point it occurs to me that circling my jar of spiders is quite possibly the worst of it. It's so neither here nor there. I give up. Out of sheer exhaustion, I take off the lid and slide in. What else is there to do? I tell them to go ahead, eat me alive…They're only too happy to oblige. The white noise gradually subsides and they set to work, sucking the sweet, juicy marrow of hope from the bones of all my constructions. (Somewhere a feast is going on )…One after another the buildings collapse, until all hope is gone and I'm alone in the rubble….I know this place. It's flat and empty and dead. There's nowhere left to run and nothing left to hide. After a long while, I notice the quiet: bleak, but oddly relaxing. No straining, nothing to hold up. There seems to be something left of me as well, though I'd be hard pressed to give it a name. It finally dawns on me that I've made it through the switcheroo. Background has become foreground. I'm now the thing I was running from - the formless ocean of awareness itself.
My sense of an impending thunderstorm has dissolved. It was apparently a feature of life on the run. Now the spiders are all over there, where the foreground used to be. They look small and hectic from here, more like ants. Noisily milling about…Me, I'm the emptiness inside the jar, though the jar itself has vanished. I'm spacious and peaceful and vast…I like this place. As always, I resolve to remember what a relief this is…I vow to bring myself to the feast more often…As usual, I forget and get trapped outside again. Circling the jar.

Wednesday, November 14, 2012

Giving time gives you time.

In the same vein as Monday's post, Mogilner et al. note another activity that expands our subjective sense of time:
Results of four experiments reveal a counterintuitive solution to the common problem of feeling that one does not have enough time: Give some of it away. Although the objective amount of time people have cannot be increased (there are only 24 hours in a day), this research demonstrates that people’s subjective sense of time affluence can be increased. We compared spending time on other people with wasting time, spending time on oneself, and even gaining a windfall of “free” time, and we found that spending time on others increases one’s feeling of time affluence. The impact of giving time on feelings of time affluence is driven by a boosted sense of self-efficacy. Consequently, giving time makes people more willing to commit to future engagements despite their busy schedules.

Tuesday, November 13, 2012

Mental time travel and our brain's default network.

Here is some interesting material from Østby et al. on the brain basis of the quality of our remembering the past or imagining the future:
A core brain network is engaged in remembering the past and envisioning the future. This network overlaps with the so-called default-mode network, the activity of which increases when demands for focused attention are low. Because of their shared brain substrates, an intriguing hypothesis is that default-mode activity, measured at rest, is related to performance in separate attention-focused recall and imagination tasks. However, we do not know how functional connectivity of the default-mode network is related to individual differences in reconstruction of the past and imagination of the future. Here, we show that functional connectivity of the default-mode network in children and adolescents is related to the quality of past remembering and marginally to future imagination. These results corroborate previous findings of a common neuronal substrate for memory and imagination and provide evidence suggesting that mental time travel is modulated by the task-independent functional architecture of the default-mode network in the developing brain. A further analysis showed that local cortical arealization also contributed to explain recall of the past and imagination of the future, underscoring the benefits of studying both functional and structural properties to understand the brain basis for complex human cognition.

Monday, November 12, 2012

Awe is good for you…

What could most of us could do to chill out and expand our subjective sense of time? Feel a sense of awe more often! Rudd et. al. do a series of experiments illustrating that it expands our perception of time, alters decision making, and enhances well-being.

In a first experiment the authors examined whether awe would alter time perception by first manipulating whether people were induced to feel awe or happiness and then having them rate self-perceived time availability. A second experiment examined whether feeling awe, relative to feeling happiness, would alter time perception (i.e., impatience) and, in turn, willingness to donate time. A third experiment tested whether awe, compared with a neutral state, would increase participants’ choice of experiential (vs. material) goods and momentary life satisfaction, two outcomes that they hypothesized would follow from awe’s ability to expand perceptions of time. In experimental versus control subjects, awe was elicited by reliving a memory, reading a brief story, or even watching a 60-s commercial (the awe-eliciting commercial depicted people in city streets and parks encountering and interacting with vast, mentally overwhelming, and seemingly realistic images, such as waterfalls, whales, and astronauts in space.)

And, here is their abstract:
When do people feel as if they are rich in time? Not often, research and daily experience suggest. However, three experiments showed that participants who felt awe, relative to other emotions, felt they had more time available (Experiments 1 and 3) and were less impatient (Experiment 2). Participants who experienced awe also were more willing to volunteer their time to help other people (Experiment 2), more strongly preferred experiences over material products (Experiment 3), and experienced greater life satisfaction (Experiment 3). Mediation analyses revealed that these changes in decision making and well-being were due to awe’s ability to alter the subjective experience of time. Experiences of awe bring people into the present moment, and being in the present moment underlies awe’s capacity to adjust time perception, influence decisions, and make life feel more satisfying than it would otherwise.

Friday, November 09, 2012

Decreased amygdala neuroplasticity linked to early-life anxious temperament.

Some interesting work from the research groups of my University of Wisconsin colleagues Ned Kalin and Richard Davidson that suggests that altered amygdala neuroplasticity may play a role the early dispositional risk to develop anxiety and depression.:
Children with anxious temperament (AT) are particularly sensitive to new social experiences and have increased risk for developing anxiety and depression. The young rhesus monkey is optimal for studying the origin of human AT because it shares with humans the genetic, neural, and phenotypic underpinnings of complex social and emotional functioning. In vivo imaging in young monkeys demonstrated that central nucleus of the amygdala (Ce) metabolism is relatively stable across development and predicts AT. Transcriptome-wide gene expression, which reflects combined genetic and environmental influences, was assessed within the Ce. Results support a maladaptive neurodevelopmental hypothesis linking decreased amygdala neuroplasticity to early-life dispositional anxiety. For example, high AT individuals had decreased mRNA expression of neurotrophic tyrosine kinase, receptor, type 3 (NTRK3). Moreover, variation in Ce NTRK3 expression was inversely correlated with Ce metabolism and other AT-substrates. These data suggest that altered amygdala neuroplasticity may play a role the early dispositional risk to develop anxiety and depression.

Thursday, November 08, 2012

Biology of social adversity.

PNAS has done a special issue on the biology of adversity. I mention only a few of the articles here:

Ziol-Guest et al. show that low income, particularly in very early childhood (between the prenatal and second year of life), is associated with increases in early-adult hypertension, arthritis, and limitations on activities of daily living. Moreover, these relationships and particularly arthritis partially account for the associations between early childhood poverty and adult productivity as measured by adult work hours and earnings. The results suggest that the associations between early childhood poverty and these adult disease states may be immune-mediated.

McDade looks at studies of inflammatory processes involved in a wide range of chronic degenerative diseases in low income populations in the Philippines and lowland Ecuador that reveal now low levels of chronic inflammation, despite higher burdens of infectious disease, point to nutritional and microbial exposures in infancy as important determinants of inflammation in adulthood.

Hostinar et al. look at associations between early life adversity and executive function in children adopted internationally from orphanages, providing evidence that early life adversity is associated with significant reductions in executive function performance on a developmentally sensitive battery of laboratory executive fundtion tasks that measure cognitive flexibility, working memory, and inhibitory control.



Wednesday, November 07, 2012

Empathy represses analytic thought, and vice versa.

Jack et al. have performed a study (online in accepted articles in the journal Neuroimage) observing brain activity in subjects while they were engaged in social versus physical analytical contexts. When the network of neurons that allows us to empathize becomes more active, it suppresses the network used for analysis. When the analytic network is more active, ability to empathize with the human effects of our actions is repressed. Here is their abstract (a bit klutzy, but does the job), and two useful summary figures from the paper.
Two lines of evidence indicate that there exists a reciprocal inhibitory relationship between opposed brain networks. First, most attention-demanding cognitive tasks activate a stereotypical set of brain areas, known as the task-positive network and simultaneously deactivate a different set of brain regions, commonly referred to as the task negative or default mode network. Second, functional connectivity analyses show that these same opposed networks are anti-correlated in the resting state. We hypothesize that these reciprocally inhibitory effects reflect two incompatible cognitive modes, each of which is directed towards understanding the external world. Thus, engaging one mode activates one set of regions and suppresses activity in the other. We test this hypothesis by identifying two types of problem-solving task which, on the basis of prior work, have been consistently associated with the task positive and task negative regions: tasks requiring social cognition, i.e., reasoning about the mental states of other persons, and tasks requiring physical cognition, i.e., reasoning about the causal/mechanical properties of inanimate objects. Social and mechanical reasoning tasks were presented to neurologically normal participants during fMRI. Each task type was presented using both text and video clips. Regardless of presentation modality, we observed clear evidence of reciprocal suppression: social tasks deactivated regions associated with mechanical reasoning and mechanical tasks deactivated regions associated with social reasoning. These findings are not explained by self-referential processes, task engagement, mental simulation, mental time travel or external vs. internal attention, all factors previously hypothesized to explain default mode network activity. Analyses of resting state data revealed a close match between the regions our tasks identified as reciprocally inhibitory and regions of maximal anti-correlation in the resting state. These results indicate the reciprocal inhibition is not attributable to constraints inherent in the tasks, but is neural in origin. Hence, there is a physiological constraint on our ability to simultaneously engage two distinct cognitive modes. Further work is needed to more precisely characterize these opposing cognitive domains.


Tuesday, November 06, 2012

Physiological benefits of leadership - Importance of a sense of control

An edited paste-up from Sapolsky's brief review pointing to work of Sherman et al. showing that leaders feeling a sense of control have lower stress levels.
Studies on primates have shown complex relationships between social dominance, physiology, and health among primates...basal cortisol levels in nonhuman primates do not so much reflect social rank as the meaning of social rank in a particular species and social group. Similar studies in humans have been challenging, because humans belong to multiple hierarchies (for example, one can have both a low position in a corporation and also be a respected church leader), and typically the one in which they rank highest is valued most. Sherman et al. have studied a population of governmental and military leaders (with equal numbers of men and women) who had been sent to an executive training program. Subjects came from a range of midlevel ranks (e.g., officers up to the rank of colonel in the army); had been in leadership positions for an average of more than 3 y; and were presumably well-regarded, given their selection by their organization for this honor. As the key findings, compared with age, sex, and ethnicity-matched nonleader controls, and after controlling for lifestyle health factors (e.g., diet, level of exercise), leaders had substantially lower resting cortisol levels and lower levels of self-reported anxiety. Thus, within this example of hierarchical stratification, high rank carries physiological and psychological advantages.
Here is the Sherman et al. abstract:
As leaders ascend to more powerful positions in their groups, they face ever-increasing demands. As a result, there is a common perception that leaders have higher stress levels than nonleaders. However, if leaders also experience a heightened sense of control—a psychological factor known to have powerful stress-buffering effects—leadership should be associated with reduced stress levels. Using unique samples of real leaders, including military officers and government officials, we found that, compared with nonleaders, leaders had lower levels of the stress hormone cortisol and lower reports of anxiety (study 1). In study 2, leaders holding more powerful positions exhibited lower cortisol levels and less anxiety than leaders holding less powerful positions, a relationship explained significantly by their greater sense of control. Altogether, these findings reveal a clear relationship between leadership and stress, with leadership level being inversely related to stress.
Further notes from Sapolsky's review:
...although both low-cortisol and low-anxiety levels correlated with leadership, neither was correlated with the other. This supports a literature that links anxiety more closely to elevated activity of the other main branch of the stress response (i.e., the sympathetic nervous system and epinephrine secretion) than to elevated cortisol secretion...The study reported additional, subtle findings. One concerned a critical mediating psychological variable in the leaders. An extensive literature shows that for the same external stressor, subjects feel less subjectively stressed, activate less of a stress response, and are less at risk for a stress-related disease if they feel a sense of control.
Both having a greater total number of subordinates and greater levels of authority were associated with a greater sense of personal control, as well as with lower levels of cortisol and anxiety; this certainly makes intuitive sense. However, having a greater number of subordinates to manage directly was not associated with those salutary psychological and physiological end points. This lends support to the stereotypical bellyaching of the office manager who says, “It’s not so much that I’m the boss of X number of people; it’s more like I have X number of bosses.”

Monday, November 05, 2012

Oxytocin facilitates protective responses to aversive social stimuli in men..

More in the thread from last Friday's post, in this case on how our brain biases responses to positive and negative social stimuli. In spite of the fact that oxytocin reduces reactivity of the amygdala to negative social stimuli, protective responses are enhanced by a pathway that appears to recruit the insula. From Streipens et al.:
The neuropeptide oxytocin (OXT) can enhance the impact of positive social cues but may reduce that of negative ones by inhibiting amygdala activation, although it is unclear whether the latter causes blunted emotional and mnemonic responses. In two independent double-blind placebo-controlled experiments, each involving over 70 healthy male subjects, we investigated whether OXT affects modulation of startle reactivity by aversive social stimuli as well as subsequent memory for them. Intranasal OXT potentiated acoustic startle responses to negative stimuli, without affecting behavioral valence or arousal judgments, and biased subsequent memory toward negative rather than neutral items. A functional MRI analysis of this mnemonic effect revealed that, whereas OXT inhibited amygdala responses to negative stimuli, it facilitated left insula responses for subsequently remembered items and increased functional coupling between the left amygdala, left anterior insula, and left inferior frontal gyrus. Our results therefore show that OXT can potentiate the protective and mnemonic impact of aversive social information despite reducing amygdala activity, and suggest that the insula may play a role in emotional modulation of memory.

Friday, November 02, 2012

A selective magnetic zap can alter belief formation in our brains.

Dolan and collaborators continue the thread of work I mentioned first in a post last year, on our brain's rose colored glasses, how we are more likely to remember and recall pleasant than aversive stimuli. Here they show that this suppression of bad input can be blocked:
Humans form beliefs asymmetrically; we tend to discount bad news but embrace good news. This reduced impact of unfavorable information on belief updating may have important societal implications, including the generation of financial market bubbles, ill preparedness in the face of natural disasters, and overly aggressive medical decisions. Here, we selectively improved people’s tendency to incorporate bad news into their beliefs by disrupting the function of the left (but not right) inferior frontal gyrus using transcranial magnetic stimulation, thereby eliminating the engrained “good news/bad news effect.” Our results provide an instance of how selective disruption of regional human brain function paradoxically enhances the ability to incorporate unfavorable information into beliefs of vulnerability.

Thursday, November 01, 2012

Are drug effects and placebo effects additive or synergistic?

Atlas et al. make observations that suggest that drug and placebo effects are not synergistic:
Placebo treatments and opiate drugs are thought to have common effects on the opioid system and pain-related brain processes. This has created excitement about the potential for expectations to modulate drug effects themselves. If drug effects differ as a function of belief, this would challenge the assumptions underlying the standard clinical trial. We conducted two studies to directly examine the relationship between expectations and opioid analgesia. We administered the opioid agonist remifentanil to human subjects during experimental thermal pain and manipulated participants' knowledge of drug delivery using an open-hidden design. This allowed us to test drug effects, expectancy (knowledge) effects, and their interactions on pain reports and pain-related responses in the brain. Remifentanil and expectancy both reduced pain, but drug effects on pain reports and fMRI activity did not interact with expectancy. Regions associated with pain processing showed drug-induced modulation during both Open and Hidden conditions, with no differences in drug effects as a function of expectation. Instead, expectancy modulated activity in frontal cortex, with a separable time course from drug effects. These findings reveal that opiates and placebo treatments both influence clinically relevant outcomes and operate without mutual interference.

Wednesday, October 31, 2012

I R’ Us - a waking mashup

When I am going through the daily transition from the last bit of REM sleep to having an awake self I frequently find articles I have recently noted appear in mind in an associated cluster. Thus the title of this post, which tries to point to our delusion that each of us is a tidy "I" that is running its own show. The chunks that come together are:
1). A review by Ezenwa et al. as well as an excellent article by Michael Specter in The New Yorker ('Germs are Us') discuss the microbiome of bacteria, viruses, and fugi whose cells vastly outnumber our own and whose genes outnumber our own by least 100 times. These 'invaders' influence not only our behavior but also our physiology and resistance to disease. We are being managed by a much larger ensemble of creatures than the "I" that writes or reads these lines.
2). A piece by Paul summarizes the powerful effect that social factors and stereotypes can have on our performance. And finally,
3).Nick Bilton writes on how our social boundaries and privacy are being erased as people are watching and reporting on us on Twitter, Facebook, Foursquare, Path and an interminable list of other social networks. Our identities diffuse into the public sphere, and we don't get to choose what show we are going to be on...
The common thread here is the message that our lives are being run by a vast army of creatures, microscopic to human size, that we usually take to be external to our "I".

Tuesday, October 30, 2012

Mouse song: features similar to human and bird song.

A MindBlog reader has pointed out to me an interesting article by Arriaga et al. that notes that mice courtship ultrasonic sound has some anatomical features and limited learning abilities previously thought unique to humans and birds. Their abstract:
Humans and song-learning birds communicate acoustically using learned vocalizations. The characteristic features of this social communication behavior include vocal control by forebrain motor areas, a direct cortical projection to brainstem vocal motor neurons, and dependence on auditory feedback to develop and maintain learned vocalizations. These features have so far not been found in closely related primate and avian species that do not learn vocalizations. Male mice produce courtship ultrasonic vocalizations with acoustic features similar to songs of song-learning birds. However, it is assumed that mice lack a forebrain system for vocal modification and that their ultrasonic vocalizations are innate. Here we investigated the mouse song system and discovered that it includes a motor cortex region active during singing, that projects directly to brainstem vocal motor neurons and is necessary for keeping song more stereotyped and on pitch. We also discovered that male mice depend on auditory feedback to maintain some ultrasonic song features, and that sub-strains with differences in their songs can match each other's pitch when cross-housed under competitive social conditions. We conclude that male mice have some limited vocal modification abilities with at least some neuroanatomical features thought to be unique to humans and song-learning birds. To explain our findings, we propose a continuum hypothesis of vocal learning.

Monday, October 29, 2012

Brain correlates of switching consciousness on and off again

Kock points in Scientific American Mind to work by Långsjö et al. (open access), who image the neural core of consciousness. They performed MRI imaging of patients recovering from propofol, dexmedetomidine, or sevoflurane anesthesia. Here is their abstract, followed by a key figure from the paper:
One of the greatest challenges of modern neuroscience is to discover the neural mechanisms of consciousness and to explain how they produce the conscious state. We sought the underlying neural substrate of human consciousness by manipulating the level of consciousness in volunteers with anesthetic agents and visualizing the resultant changes in brain activity using regional cerebral blood flow imaging with positron emission tomography. Study design and methodology were chosen to dissociate the state-related changes in consciousness from the effects of the anesthetic drugs. We found the emergence of consciousness, as assessed with a motor response to a spoken command, to be associated with the activation of a core network involving subcortical and limbic regions that become functionally coupled with parts of frontal and inferior parietal cortices upon awakening from unconsciousness. The neural core of consciousness thus involves forebrain arousal acting to link motor intentions originating in posterior sensory integration regions with motor action control arising in more anterior brain regions. These findings reveal the clearest picture yet of the minimal neural correlates required for a conscious state to emerge.
Colored areas indicate the parts of the brain that first come online when patients emerge from consciousness after being anesthetized with one of two different agents. The three critical regions are the anterior cingulate cortex (a), the thalamus (b) and parts of the brain stem (c).

Saturday, October 27, 2012

A new study on implicit attitudes and voting..

Following my post on implicit attitudes and voting I have received an email from a group of collaborators doing further studies on the same issue. They need to recruit undecided voters and request that I post this note including the URL of their study in MindBlog.

Friday, October 26, 2012

Gender bias is alive and well in academic science.

Handelsman and collaborators do a rather clear study on how the academy works, showing that science faculties favor male students:
Despite efforts to recruit and retain more women, a stark gender disparity persists within academic science. Abundant research has demonstrated gender bias in many demographic groups, but has yet to experimentally investigate whether science faculty exhibit a bias against female students that could contribute to the gender disparity in academic science. In a randomized double-blind study (n = 127), science faculty from research-intensive universities rated the application materials of a student—who was randomly assigned either a male or female name—for a laboratory manager position. Faculty participants rated the male applicant as significantly more competent and hireable than the (identical) female applicant. These participants also selected a higher starting salary and offered more career mentoring to the male applicant. The gender of the faculty participants did not affect responses, such that female and male faculty were equally likely to exhibit bias against the female student. Mediation analyses indicated that the female student was less likely to be hired because she was viewed as less competent. We also assessed faculty participants’ preexisting subtle bias against women using a standard instrument and found that preexisting subtle bias against women played a moderating role, such that subtle bias against women was associated with less support for the female student, but was unrelated to reactions to the male student. These results suggest that interventions addressing faculty gender bias might advance the goal of increasing the participation of women in science.

Thursday, October 25, 2012

Resilience to stress replacing happiness as fashionable research topic

Nature has published a special supplement on Stress and Relilience, a topic also of major emphasis in Richard Davidson's new book. I thought the article by Nestler on epigenetic regulation of resilience to stress was particularly interesting, especially following on this past Monday's post (look there for reminder of definitions of epigenetic changes, etc.) His research is on epigenetic differences between mice that are resilient versus susceptible to stress:
We can make susceptible mice resilient by blocking or inducing epigenetic modifications to certain genes or by altering the expression patterns of those genes to mimic the epigenetic tweaks. Likewise, epigenetic modifications and gene expression can be altered in resilient mice to make them more susceptible.
Other groups have found similar epigenetic alterations that last a lifetime. For instance, rat pups that are rarely licked and groomed by their mothers are more susceptible to stress later in life than are pups with more diligent carers. They are less adventurous than better-cared-for offspring and put up less of a fight in unpleasant situations (such as being placed in a beaker of water). Moreover, the females are less nurturing towards their own offspring. Epigenetic modifications seem to occur at several genes in the hippocampus in response to how much grooming young rats receive, and these alterations persist into adulthood.
These findings are likely to hold up in humans. For example, researchers have found that the genes identified in the rat-grooming studies were more methylated in the hippocampi of suicide victims who had experienced trauma as children than in the those of people who had died from suicide or natural causes and whose childhoods were normal. Likewise, our findings in mice given cocaine mirror epidemiological studies from the past few decades that have linked drug abuse, obesity and conditions such as multiple sclerosis, diabetes and heart disease to increased susceptibility to stress in humans.
More controversial is whether animals inherit epigenetic vulnerability to stress. According to this notion, epigenetic modifications in sperm or eggs drive aberrant patterns of gene expression in the next generation. Several groups have reported that male mice exposed to stress — by being removed from their mothers as pups or exposed to more aggressive mice as adults, for example — produce offspring that are more vulnerable to stress.
A mechanism is still elusive. Exposure to stress could somehow corrupt the male mouse's behaviour or affect some signalling molecule in his semen such that his partner alters her care for their young. Another possibility is that stress-linked epigenetic 'marks' in the sperm affect the development of offspring. No causal evidence yet links epigenetic changes in sperm to altered behaviour in offspring.

Wednesday, October 24, 2012

Mechanism of unconscious internal bias in our choices

What's actually happening when we make choices that do not seem to be justifiable on purely economic or logical grounds? Wimmer and Shohamy do some interesting work showing how the hippocampus can instill an unconscious bias in our valuations, whereby an object that is not highly valued on its own, increases in value when it becomes implicitly associated with a truly high-value object. As a consequence, we then end up preferring the associated object over a neutral object of equal objective value while not really knowing why. The abstract:
Every day people make new choices between alternatives that they have never directly experienced. Yet, such decisions are often made rapidly and confidently. Here, we show that the hippocampus, traditionally known for its role in building long-term declarative memories, enables the spread of value across memories, thereby guiding decisions between new choice options. Using functional brain imaging in humans, we discovered that giving people monetary rewards led to activation of a preestablished network of memories, spreading the positive value of reward to nonrewarded items stored in memory. Later, people were biased to choose these nonrewarded items. This decision bias was predicted by activity in the hippocampus, reactivation of associated memories, and connectivity between memory and reward regions in the brain. These findings explain how choices among new alternatives emerge automatically from the associative mechanisms by which the brain builds memories. Further, our findings demonstrate a previously unknown role for the hippocampus in value-based decisions.
The details of the experiment are kind of neat. I pass on two figures:


Fig. 1 The task consists of three phases: association learning, reward learning, and decision-making. (A) In the association phase, participants were exposed to a series of pairs of pictures (S1 and S2 stimuli) while performing a cover task to detect “target” upside-down pictures. S1 stimuli were either face, scene, or body part pictures; S2 stimuli were circle images. (B) In the reward phase, participants learned through classical conditioning that half of the S2 stimuli were followed by a monetary reward (S2+), whereas the other S2 stimuli were followed by a neutral outcome (no reward, S2–). S1 stimuli never appeared in this stage. (C) In the decision phase, participants were asked to decide between two stimuli (both S1 or both S2) for a possible monetary win. No feedback was provided, and all gains were awarded at the end of the experiment. Decision bias was operationalized as the tendency to choose S1+ over S1– stimuli in this phase.

Fig. 3 Reactivation of category-specific visual areas during the first half of the reward phase is related to subsequent decision bias. (A) Example participant region of interest masks (derived from the association phase) for body, face, and scene S1 stimuli. Masks were applied to S2 presentations during the reward phase. (B) S2 presentation elicits activation in visual regions responsive to associated S1 stimuli when participants later exhibit decision bias. Error bars indicate ±SEM; a.u., arbitrary units.

Tuesday, October 23, 2012

Memory fading? Try some dopamine...

From Chowdhury et al. in the Journal of Neuroscience:
Activation of the hippocampus is required to encode memories for new events (or episodes). Observations from animal studies suggest that, for these memories to persist beyond four to six hours, a release of dopamine generated by strong hippocampal activation is needed. This predicts that dopaminergic enhancement should improve human episodic memory persistence also for events encoded with weak hippocampal activation. Here, using pharmacological functional MRI (fMRI) in an elderly population in which there is a loss of dopamine neurons as part of normal aging, we show this very effect. The dopamine precursor levodopa led to a dose-dependent (inverted U-shape) persistent episodic memory benefit for images of scenes when tested after six hours, independent of whether encoding-related hippocampal fMRI activity was weak or strong (U-shaped dose–response relationship). This lasting improvement even for weakly encoded events supports a role for dopamine in human episodic memory consolidation, albeit operating within a narrow dose range.

Monday, October 22, 2012

A revolution in understanding our genetics, personality, and disease.

A revolution is taking place. It challenges the basic genetic orthodoxy of the past century, changing what all of us thought we knew. This is dense material, but very important, and I would urge general readers to try to have a go at it. (Few MindBlog readers would be up for taking on the Wonkish details of Nelson et al.'s paper on 'epigenetic effects of…cytidine deaminase deficiency…etc.' - so I want to pass on edited and rearranged clips from a commentary by Mattick that shows (still Wonkish, but less so) the context and importance of this and similar studies):
Nelson et al. present intriguing evidence that challenges the fundamental tenets of genetics. It has long been assumed that the inherited contribution to phenotype is embedded in DNA sequence variations in, and interactions between, the genes endogenous to the organism, i.e., alleles derived from parents with some degree of de novo variation. This assumption underlies most genetic analysis, including the fleet of genome-wide association studies launched in recent years to identify genomic loci that influence complex human traits and diseases....the perplexing and much debated surprise has been that most genome-wide association studies have superficially failed to locate more than a small percentage of the inherited component of complex traits. This may be a result of a number of possibilities...including... intergenerational epigenetic inheritance, which is not polled by DNA sequence. However, the latter has not thus far been paid much attention or given much credence as a major factor.
Now Nelson et al. provide data suggesting that epigenetic inheritance may be far more important and pervasive than expected. (Mechanistically, epigenetic memory is embedded in DNA methylation and/or histone modifications, which are thought to be erased in germ cells, but may not be, at least completely, as some chromatin structure appears to be preserved. Some information may also be cotransmitted by RNA.) Their findings add to a growing list of studies indicating that genetic influence of ancestral variants can commonly reach through multiple generations and rival conventional inheritance in strength. These include the demonstrations, with considerable molecular and genetic detail, of epigenetic inheritance (i.e., “paramutation”) in plants, and, although still somewhat controversial, in animals.
Although the genetics are complex, Nelson et al.show in an elegant and comprehensive series of analyses that grand-maternal (but not grand-paternal) heterozygosis for a null allele of the Apobec1 cytidine deaminase gene modulates testicular germ cell tumor susceptibility and embryonic viability in male (mouse) descendants that do not carry the null allele, an effect that persists for at least three generations.
...here is now good evidence that epigenetic inheritance is RNA-mediated...as it is becoming clear that a major function of the large numbers of noncoding RNAs that are differentially expressed from the genome is to direct chromatin-modifying complexes to their sites of action. This conclusion is consistent with the recent findings of the ENCODE project, suggesting that much if not most of the human genome may be functional, and explains the informational basis of the extraordinary precision and complexity of the epigenetic superstructure of the genome in different cells required to specify developmental architecture.
The available evidence not only suggests an intimate interplay between genetic and epigenetic inheritance, but also that this interplay may involve communication between the soma and the germline. This idea contravenes the so-called Weismann barrier, sometimes referred to as Biology’s Second Law, which is based on flimsy evidence and a desire to distance Darwinian evolution from Lamarckian inheritance at the time of the Modern Evolutionary Synthesis. However, the belief that the soma and germline do not communicate is patently incorrect—as demonstrated by the multigenerational inheritance of RNAi-mediated phenotypes delivered to somatic cells in Caenorhabditis elegans.
Thus, if RNA editing can alter hardwired genetic information in a context-dependent manner, and thereby alter epigenetic memory, it is feasible that not only allelic but also environmental history may shape phenotype, and provide a far more plastic and dynamic inheritance platform than envisaged by the genetic orthodoxy of the past century. Morever...RNA, more than DNA, may be the computational engine of the evolution and ontogeny of developmentally complex and cognitively advanced organisms

Friday, October 19, 2012

Learning new information during sleep.

Arzi et al. do an ingenious experiment to show that we can do associative learning during our sleep. We can associate a sound with a pleasant or unpleasant odor and react, both while still asleep and after waking, with a deeper or shallower breath. This does not, however, represent the kind of 'sleep learning' long sought by students who unsuccessfully try to remember scientific or literary facts needed for an exam by playing a tape softly during sleep. Here is the abstract:
During sleep, humans can strengthen previously acquired memories, but whether they can acquire entirely new information remains unknown. The nonverbal nature of the olfactory sniff response, in which pleasant odors drive stronger sniffs and unpleasant odors drive weaker sniffs, allowed us to test learning in humans during sleep. Using partial-reinforcement trace conditioning, we paired pleasant and unpleasant odors with different tones during sleep and then measured the sniff response to tones alone during the same nights' sleep and during ensuing wake. We found that sleeping subjects learned novel associations between tones and odors such that they then sniffed in response to tones alone. Moreover, these newly learned tone-induced sniffs differed according to the odor pleasantness that was previously associated with the tone during sleep. This acquired behavior persisted throughout the night and into ensuing wake, without later awareness of the learning process. Thus, humans learned new information during sleep.

Thursday, October 18, 2012

The Neurochemistry of Storytelling.

Having in the previous post just made an ill-tempered dump on one kind of popularization, I decide to be inconsistent and now pass on this nice piece with a little less pizazz from the Brain Pickings Newsletter, on how storytelling can engage our brain neurochemistry associated with stress and empathy. It is a very effective and touching piece, and I recommend that you watch the video below:

Wednesday, October 17, 2012

Brain Showbiz...

Put me down as a curmudgeonly old fart, but I'm not getting a 'gee whiz' response to a recent promotional email asking for publicity on a rhythm and the brain project. It's cute, the graphics are kewl, but the science is out to lunch - it seems to me more like publicity seeking and self promotion masquerading as brain science.

Tuesday, October 16, 2012

Conscious awareness not required for our placebo or nocebo responses.

Interesting observations from Jensen et al. They first condition a placebo (beneficial) or nocebo (adverse) reponse to a thermal pain stimulus, and then find subliminal (non-conscious) presentation of the conditioning cues elicits the same responses. Their abstract:
The dominant theories of human placebo effects rely on a notion that consciously perceptible cues, such as verbal information or distinct stimuli in classical conditioning, provide signals that activate placebo effects. However, growing evidence suggest that behavior can be triggered by stimuli presented outside of conscious awareness. Here, we performed two experiments in which the responses to thermal pain stimuli were assessed. The first experiment assessed whether a conditioning paradigm, using clearly visible cues for high and low pain, could induce placebo and nocebo responses. The second experiment, in a separate group of subjects, assessed whether conditioned placebo and nocebo responses could be triggered in response to nonconscious (masked) exposures to the same cues. A total of 40 healthy volunteers (24 female, mean age 23 y) were investigated in a laboratory setting. Participants rated each pain stimulus on a numeric response scale, ranging from 0 = no pain to 100 = worst imaginable pain. Significant placebo and nocebo effects were found in both experiment 1 (using clearly visible stimuli) and experiment 2 (using nonconscious stimuli), indicating that the mechanisms responsible for placebo and nocebo effects can operate without conscious awareness of the triggering cues. This is a unique experimental verification of the influence of nonconscious conditioned stimuli on placebo/nocebo effects and the results challenge the exclusive role of awareness and conscious cognitions in placebo responses.

Monday, October 15, 2012

Clever crows! Now shown to reason about hidden causes.

Behavioral studies on New Caledonian crows, especially over the past twenty years, continue to yield amazing results. (A video I first posted for my Biology of Mind course over ten years ago showing some of this earlier work has received 125,000 viewings!). Taylor et al. now demonstrate reasoning about hidden causes:
The ability to make inferences about hidden causal mechanisms underpins scientific and religious thought. It also facilitates the understanding of social interactions and the production of sophisticated tool-using behaviors. However, although animals can reason about the outcomes of accidental interventions, only humans have been shown to make inferences about hidden causal mechanisms. Here, we show that tool-making New Caledonian crows react differently to an observable event when it is caused by a hidden causal agent. Eight crows watched two series of events in which a stick moved. In the first set of events, the crows observed a human enter a hide, a stick move, and the human then leave the hide. In the second, the stick moved without a human entering or exiting the hide. The crows inspected the hide and abandoned probing with a tool for food more often after the second, unexplained series of events. This difference shows that the crows can reason about a hidden causal agent. Comparative studies with the methodology outlined here could aid in elucidating the selective pressures that led to the evolution of this cognitive ability.

Friday, October 12, 2012

Kids as little scientists - early academics can be misguided

A review article by Gopnik offers an interesting perspective:
New theoretical ideas and empirical research show that very young children’s learning and thinking are strikingly similar to much learning and thinking in science. Preschoolers test hypotheses against data and make causal inferences; they learn from statistics and informal experimentation, and from watching and listening to others. The mathematical framework of probabilistic models and Bayesian inference can describe this learning in precise ways. These discoveries have implications for early childhood education and policy. In particular, they suggest both that early childhood experience is extremely important and that the trend toward more structured and academic early childhood programs is misguided.

Thursday, October 11, 2012

Opps! Sex does decrease human male lifespan.

Animal studies have suggested that castration increases lifespan in males, and now Korean researchers have examined genealogy records and lifespan of 81 Korean eunuchs to find that their average lifespan is ~14-19 years longer than that of non-castrated men of similar class. (I doubt this finding will lead to an uptick in voluntary male castrations, the trade off of minus fifteen years for what our male sex hormones make possible doesn’t seem so bad...) The abstract:
Although many studies have shown that there are trade-offs between longevity and reproduction, whether such trade-offs exist in humans has been a matter of debate. In many species, including humans, males live shorter than females, which could be due to the action of male sex hormones. Castration, which removes the source of male sex hormones, prolongs male lifespan in many animals, but this issue has been debated in humans. To examine the effects of castration on longevity, we analyzed the lifespan of historical Korean eunuchs. Korean eunuchs preserved their lineage by adopting castrated boys. We studied the genealogy records of Korean eunuchs and determined the lifespan of 81 eunuchs. The average lifespan of eunuchs was 70.0 ± 1.76 years, which was 14.4–19.1 years longer than the lifespan of non-castrated men of similar socio-economic status. Our study supports the idea that male sex hormones decrease the lifespan of men.

Wednesday, October 10, 2012

Followup on evolutionary psychology as ' just so stories'

A comment on my Sept. 28 post has passed on a number of excellent response to the book review I was noting in that post. I was remiss (lazy) in not taking to task one absurd contention of the reviewer, namely that "you don’t have to know about the evolution of an organ in order to understand it." (a third of my Biology of Mind Book argued the contrary.) After Jabr notes in his Scientific American comments several examples of how understanding the evolution of different brain areas has enhanced understanding and medical practice, he gives this nice analogy:
Studying the brain and mind in ignorance of its vast evolutionary tale does not make sense. It would be equivalent to an archaeologist discovering the remains of an enormous tapestry, slicing out a particular figure from the cloth and claiming that he could learn everything he needs to know by examining that figure in isolation. Even if the archaeologist described the figure in exquisite detail, taking it apart thread by thread and sewing it back together, he would remain willfully oblivious of the whole story. In the same way, disregarding the human brain’s history limits psychology and neuroscience to a paltry understanding of our brains and minds.
The comment also points to Kurzban and Gottschall as offering further commentary.

Also, let me note this comment on the Sept 28 post by Jim Birch:
I'm a little surprised by the animosity directed at evolutionary psychology. For me, it has provided revolutionary insights and understanding. In particular, the general notion that in biology, energy is not wasted, it is utilized adaptively. Under evolution, "adaptive" is not local in time and space but statistically selected over a period and range of the species' evolution.
This gives, or actually requires, a new way of interpreting any human behaviour: as statistically adaptive. And in doing so, it blasts away the incoherent mass of narrative explanations that have been conventionally applied. Our "craziest" tendencies like dying on Everest or blowing life savings on poker machines are no longer down to Freudian death wishes or moral failings (etc) but can be seen as adaptive behaviours operating badly, or even just out of context.
Of course, no one was around in the Pleistocene recording behaviours and survival rates so there's a need for speculation, modelling and indirect evidence. It is this that opens the field up to "just-so stories" charge. There is also the potential for use of selective evidence - to simplistically support preferred moral positions, eg, tooth-and-claw v. cooperative vision of "human nature". However, this is not a problem that is peculiar to evolutionary psychology, it's a perenial problem for science, especially new fields. No doubt the situation will improve as things develop and there's a lot of baby in the bathwater of evolutionary psychology.

Tuesday, October 09, 2012

Young children and adults: intrinsically motivated to see others helped

This interesting piece from Tomasello and collaborators:
Young children help other people, but it is not clear why. In the current study, we found that 2-year-old children’s sympathetic arousal, as measured by relative changes in pupil dilation, is similar when they themselves help a person and when they see that person being helped by a third party (and sympathetic arousal in both cases is different from that when the person is not being helped at all). These results demonstrate that the intrinsic motivation for young children’s helping behavior does not require that they perform the behavior themselves and thus “get credit” for it, but rather requires only that the other person be helped. Thus, from an early age, humans seem to have genuine concern for the welfare of others.
And, Rand et al. use economic games with adult subjects to demonstrate that cooperation is intuitive, because cooperative heuristics are developed in daily life where cooperation is typically advantageous. This data adds to Kahneman's recent summary of evidence that much of human decision-making is governed by fast and automatic intuitions, rather than by slow, effortful thinking (see Kahneman, D. Thinking, Fast and Slow, Allen Lane, 2011). The Rand et al. abstract
Cooperation is central to human social behaviour. However, choosing to cooperate requires individuals to incur a personal cost to benefit others. Here we explore the cognitive basis of cooperative decision-making in humans using a dual-process framework. We ask whether people are predisposed towards selfishness, behaving cooperatively only through active self-control; or whether they are intuitively cooperative, with reflection and prospective reasoning favouring ‘rational’ self-interest. To investigate this issue, we perform ten studies using economic games. We find that across a range of experimental designs, subjects who reach their decisions more quickly are more cooperative. Furthermore, forcing subjects to decide quickly increases contributions, whereas instructing them to reflect and forcing them to decide slowly decreases contributions. Finally, an induction that primes subjects to trust their intuitions increases contributions compared with an induction that promotes greater reflection. To explain these results, we propose that cooperation is intuitive because cooperative heuristics are developed in daily life where cooperation is typically advantageous. We then validate predictions generated by this proposed mechanism. Our results provide convergent evidence that intuition supports cooperation in social dilemmas, and that reflection can undermine these cooperative impulses.

Monday, October 08, 2012

MRI of reading Jane Austen

Another totally annoying example of science by press release sans any reference to an original research article offers a glimpse at what looks like fascinating work, showing brain correlates of a kind of deep attention going with reading literature that is very different from the kind of deep attention that is focused on mastering a particular task.
In an innovative interdisciplinary study, neurobiological experts, radiologists and humanities scholars are working together to explore the relationship between reading, attention and distraction – by reading Jane Austen. Surprising preliminary results reveal a dramatic and unexpected increase in blood flow to regions of the brain beyond those responsible for "executive function," areas which would normally be associated with paying close attention to a task, such as reading, said Natalie Phillips, the literary scholar leading the project. During a series of ongoing experiments, functional magnetic resonance images track blood flow in the brains of subjects as they read excerpts of a Jane Austen novel. Experiment participants are first asked to leisurely skim a passage as they might do in a bookstore, and then to read more closely, as they would while studying for an exam. Phillips said the global increase in blood flow during close reading suggests that "paying attention to literary texts requires the coordination of multiple complex cognitive functions." Blood flow also increased during pleasure reading, but in different areas of the brain. Phillips suggested that each style of reading may create distinct patterns in the brain that are "far more complex than just work and play."
A commentary by Alan Jacobs on this work makes a further point, that we might do well to exercise various parts of our minds just as we do well to exercise various parts of our bodies. Otherwise we could end up like Charles Darwin, who felt that over time he had lost certain mental functions:
My mind seems to have become a kind of machine for grinding general laws out of large collections of facts, but why this should have caused the atrophy of that part of the brain alone, on which the higher tastes depend, I cannot conceive. A man with a mind more highly organised or better constituted than mine, would not, I suppose, have thus suffered; and if I had to live my life again, I would have made a rule to read some poetry and listen to some music at least once every week; for perhaps the parts of my brain now atrophied would thus have been kept active through use. The loss of these tastes is a loss of happiness, and may possibly be injurious to the intellect, and more probably to the moral character, by enfeebling the emotional part of our nature.

Friday, October 05, 2012

Rethinking sleep - brief wakeful resting boosts new memories over the long term.

Two recent articles point out that the prevailing notion that an eight hour chunk of sleep is required for optimum health and function is a relatively recent invention that doesn't take into account the usefulness of many varieties of sleep. Randall notes historical and contemporary evidence that other patterns are useful, and here is an abstract from Dewar et al. on how wakeful rest enhances long term consolidation of new memories:
A brief wakeful rest after new verbal learning enhances memory for several minutes. In the research reported here, we explored the possibility of extending this rest-induced memory enhancement over much longer periods. Participants were presented with two stories; one story was followed by a 10-min period of wakeful resting, and the other was followed by a 10-min period during which participants played a spot-the-difference game. In Experiment 1, wakeful resting led to significant enhancement of memory after a 15- to 30-min period and also after 7 days. In Experiment 2, this striking enhancement of memory 7 days after learning was demonstrated even when no retrievals were imposed in the interim. The degree to which people can remember prose after 7 days is significantly affected by the cognitive activity that they engage in shortly after new learning takes place. We propose that wakeful resting after new learning allows new memory traces to be consolidated better and hence to be retained for much longer.

Thursday, October 04, 2012

Regulators of prosocial and empathetic behavior.

Two pieces in the September issue of Psychological Science deal with empathetic or prosocial behavior. Grant and Dutton make observations showing that prosocial behavior is boosted more by reflecting on giving than on receiving; and Lewis et al.'s experiments give a example of how stereotypes enhance empathetic accuracy.
Grant and Dutton:
Research shows that reflecting on benefits received can make people happier, but it is unclear whether or not such reflection makes them more helpful. Receiving benefits can promote prosocial behavior through reciprocity and positive affect, but these effects are often relationship-specific, short-lived, and complicated by ambivalent reactions. We propose that prosocial behavior is more likely when people reflect on being a benefactor to others, rather than a beneficiary. The experience of giving benefits may encourage prosocial behavior by increasing the salience and strength of one’s identity as a capable, caring contributor. In field and laboratory experiments, we found that participants who reflected about giving benefits voluntarily contributed more time to their university, and were more likely to donate money to natural-disaster victims, than were participants who reflected about receiving benefits. When it comes to reflection, giving may be more powerful than receiving as a driver of prosocial behavior.
Lewis et al.:
An ideal empathizer may attend to another person’s behavior in order to understand that person, but it is also possible that accurately understanding other people involves top-down strategies. We hypothesized that perceivers draw on stereotypes to infer other people’s thoughts and that stereotype use increases perceivers’ accuracy. In this study, perceivers (N = 161) inferred the thoughts of multiple targets. Inferences consistent with stereotypes for the targets’ group (new mothers) more accurately captured targets’ thoughts, particularly when actual thought content was also stereotypic. We also decomposed variance in empathic accuracy into thought, target, and perceiver variance. Although past research has frequently focused on variance between perceivers or targets (which assumes individual differences in the ability to understand other people or be understood, respectively), the current study showed that the most substantial variance was found within targets because of differences among thoughts.

Wednesday, October 03, 2012

Idle Minds - why are our brains so active when doing ‘nothing’?

Kerri Smith does a review on the resting or default activity of our brains, what is happening when we are not focused on anything in particular, but letting our minds just rest or wander at random: After initial observations in the mid-1990s showed that the brain never really takes a break,
...studies of the resting state in its own right began to emerge. A team led by Marcus Raichle characterized activity in one such network as the brain's default mode — what they considered its baseline setting. During tasks, default-mode activity actually dropped, coming back online when the brain was no longer focusing so intensely.
The default-mode network has been joined by dozens of other flavors of resting-state network — some of which resemble the circuitry that contributes to attention, vision, hearing or movement. They seem very similar across study participants but are also dynamic, changing over time.
One idea is that the brain is running several models of the world in the background, ready for one of them to turn into reality.
Raichle favors the idea that activity in the resting state helps the brain to stay organized. The connections between neurons are continually shifting as people age and learn, but humans maintain a sense of self throughout the upheaval. Spontaneous activity might play a part in maintaining that continuity. “Connections between neurons turn over in minutes, hours, days and weeks,...The structure of the brain will be different tomorrow but we will still remember who we are.” …the brain replays and consolidates new memories at any chance it gets — even when awake.
…perhaps the activity is part of the reshaping process, tweaking connections while we idle. Several teams have reported changes in resting connectivity after language and memory tasks and motor learning… suggesting that the brain is not only thinking about supper coming up, but it's also processing the recent past and converting some of that into long-term memories. The network changes are specific to the tasks performed.

Tuesday, October 02, 2012

Interpersonal closeness and brain social reward processing

I'm passing on a graphic from Vrticka's comments on recent work by Farei et al., who have observed brain activation patterns associated with sharing positive outcomes with a friends, that are also mirrored in high subjective ratings of excitement and high skin conductance responses during the same condition, reflecting increased biological arousal.


Illustration of the dynamic “push–pull” between social approach and aversion in the affective processing module of human social interaction. According to the phylogenetic perspective of social engagement and attachment proposed by Porges, human social functioning is determined by two opposite emotional brain systems representing positive (social approach; purple) versus negative (social aversion; blue) information. Whereas the social approach module mainly includes dopaminergic pathways (ventral tegmental area, striatum, ventral medial orbitofrontal cortex), as well as the pituitary/hypothalamus as the main site of oxytocin synthesis, the social aversion module operates through brain areas involved in fear/threat (amygdala), stress (hippocampus), disgust/empathy for pain/social rejection (insula and anterior cingulate cortex), and sadness (anterior temporal pole).
Here is the Farei et al. abstract:
Everyday goals and experiences are often shared with others who may hold different places within our social networks. We investigated whether the experience of sharing a reward differs with respect to social network. Twenty human participants played a card guessing game for shared monetary outcomes with three partners: a computer, a confederate (out of network), and a friend (in network). Participants subjectively rated the experience of sharing a reward more positively with their friends than the other partners. Neuroimaging results support participants' subjective reports, as ventral striatal BOLD responses were more robust when sharing monetary gains with a friend as compared to the confederate or computer, suggesting a higher value for sharing with an in-network partner. Interestingly, ratings of social closeness covaried with this activity, resulting in a significant partner × closeness interaction; exploratory analysis showed that only participants reporting higher levels of closeness demonstrated partner-related differences in striatal BOLD response. These results suggest that reward valuation in social contexts is sensitive to distinctions of social network, such that sharing positive experiences with in-network others may carry higher value.

Monday, October 01, 2012

Want to be unhappy? Trying to be happy will do it!

I'm finding the "Anxiety" topic in the Opinionator series at the NYTimes to be a real treat. This entry by British expatriate Ruth Whippman brings back memories of a my signing on several years ago to be a talking head neuroscience expert on the  California "Make Me Happy!" Radio Show (I don't think they were all that pleased with their dyspeptic guest!). Whippman notes the American obsession with, and anxiety over, being "happy", and contrasts this with the attitudes of more stoic Britishers:
Happiness in America has become the overachiever's ultimate trophy. A vicious trump card, it outranks professional achievement and social success, family, friendship and even love…this elusive MacGuffin is creating a nation of nervous wrecks. Despite being the richest nation on earth, the United States is, according to the World Health Organization, by a wide margin, also the most anxious, with nearly a third of Americans likely to suffer from an anxiety problem in their lifetime. America's precocious levels of anxiety are not just happening in spite of the great national happiness rat race, but also perhaps, because of it.
The British are generally uncomfortable around the subject, and as a rule, don't subscribe to the happy-ever-after. It's not that we don't want to be happy, it just seems somehow embarrassing to discuss it, and demeaning to chase it, like calling someone moments after a first date to ask them if they like you….Even the recent grand spectacle of the London 2012 Olympic Games told this tale. The opening ceremony, traditionally a sparklefest of perkiness, was, with its suffragist and trade unionists, mainly a celebration of dissent, or put less grandly, complaint…Our queen, despite the repeated presence of a stadium full of her subjects urging in song that she be both happy and glorious, could barely muster a smile, staring grimly through her eyeglasses and clutching her purse on her lap as if she might be mugged.
Cynicism is the British shtick. When happiness does come our way, it is entirely without effort, as unmeritocratic as a hereditary peerage. By contrast, in America, happiness is work. Intense, nail-biting work, slogged out in motivational seminars and therapy sessions, meditation retreats and airport bookstores. For the left there's yoga, for the right, there's Jesus. For no one is there respite…The people taking part in "happiness pursuits," as a rule, don't seem very happy…The happy person would be more likely to be off doing something fun, like sitting in the park drinking.
Happiness should be serendipitous, a by-product of a life well lived, and pursuing it in a vacuum doesn't really work. This is borne out by a series of slightly depressing statistics. The most likely customer of a self-help book is a person who has bought another self-help book in the last 18 months. The General Social Survey, a prominent data-based barometer of American society, shows little change in happiness levels since 1972, when such records began. Every year, with remarkable consistency, around 33 percent of Americans report that they are "very happy." It's a fair chunk, but a figure that remains surprisingly constant, untouched by the uptick in Eastern meditation or evangelical Christianity, by Tony Robbins or Gretchen Rubin or attachment parenting. For all the effort Americans are putting into happiness, they are not getting any happier. It is not surprising, then, that the search itself has become a source of anxiety.
So here's a bumper sticker: despite the glorious weather and spectacular landscape, the people of California are probably less happy and more anxious than the people of Grimsby. So they may as well stop trying so hard.

Friday, September 28, 2012

Just so stories about the evolution of our minds.

I want to point to a very nicely done review in The New Yorker by Anthony Gottlieb, who notes a number of recent books dealing with evolutionary psychology, but mainly comments on “Homo Mysterious: Evolutionary Puzzles of Human Nature” (Oxford), a new book by David Barash, a professor of psychology and biology at the University of Washington, Seattle. The main point of critics is that most evolutionary theories purporting to explain our sexual or other behaviors as evolved adaptations to conditions faced by our paleolithic ancestors have no more validity than Rudyard Kipling's "just so" stories about how the camel got his hump or the rhinoceros his wrinkly folds of skin. One clip from the review:
A review of the methods of evolutionary psychology, published last summer in a biology journal, underlined a point so simple that its implications are easily missed. To confirm any story about how the mind has been shaped, you need (among other things) to determine how people today actually think and behave, and to test rival accounts of how these traits function. Once you have done that, you will, in effect, have finished the job of explaining how the mind works. What life was really like in the Stone Age no longer matters. It doesn’t make any practical difference exactly how our traits became established. All that matters is that they are there.

Thursday, September 27, 2012

Voting patterns: “I” value competence but “we” value social competence

(Chen et al. ask whether judgments of candidates' social competence—defined as the capacity for effective functioning in social interactions—are related to outcomes in an individualistic society (the United States) and a collectivist society (Taiwan). They replicate the earlier result that a judgment of competence does predict winners in the United States, as it does in Taiwan, and they find that judgments of social competence are also predictive, though only for elections in Taiwan. Their abstract:
This investigation distinguishes interpersonally oriented social competence from intrapersonally oriented competence. It examines the influence of voters' individualism and collectivism orientation in affecting the roles of these two dimensions in predicting electoral outcomes. Participants made judgments of personality traits based on inferences from faces of political candidates in the U.S. and Taiwan. Two social outcomes were examined: actual election results and voting support of the participants. With respect to actual electoral success, perceived competence is more important for the candidates in the U.S. than for those in Taiwan, whereas perceived social competence is more important for the candidates in Taiwan than for those in the U.S. With respect to subjective voting support, within cultural findings mirror those found cross-culturally. Competence is valued more among voters who are more individualistic, and social competence is valued more among voters who are more collectivistic. These results highlight important omissions in the social perception/judgment literature.


(excuse a techie note irrelevant to this post: I confirm the subscription of this blog to the Paperblog service under the username mdbownds)

Wednesday, September 26, 2012

Combat stress causes long term changes in brain connectivity.

Sobering results from Wingen et al.:
Prolonged stress can have long-lasting effects on cognition. Animal models suggest that deficits in executive functioning could result from alterations within the mesofrontal circuit. We investigated this hypothesis in soldiers before and after deployment to Afghanistan and a control group using functional and diffusion tensor imaging. Combat stress reduced midbrain activity and integrity, which was associated to compromised sustained attention. Long-term follow-up showed that the functional and structural changes had normalized within 1.5 y. In contrast, combat stress induced a persistent reduction in functional connectivity between the midbrain and prefrontal cortex. These results demonstrate that combat stress has adverse effects on the human mesofrontal circuit and suggests that these alterations are partially reversible.
Legend (click figure to enlarge) - Combat stress reduces functional connectivity of the midbrain with the lateral prefrontal cortex. The reduction from baseline to short-term follow-up is presented in blue. The persistent reduction from baseline to long-term follow-up at 1.5 y after military deployment is presented in green. The overlap between the short-term and long-term effects is presented in cyan.
A bit more expanded summary in their discussion:
These results show that the adverse effects of combat stress on sustained attention are related to functional and structural changes in the midbrain. These alterations normalize within 1.5 y in soldiers without psychiatric complaints, which may explain why long-term cognitive deficits following combat are mainly observed in soldiers with posttraumatic stress symptoms. In contrast to the reversible effects on the midbrain itself, its reduced interaction with the prefrontal cortex persists for at least 1.5 y. Taken together, these results suggest that the human brain can largely recover from the adverse effects of stress, supporting the view that neural plasticity in response to prolonged stress is adaptive. However, the results also reveal long-term changes within the mesofrontal network that may increase the vulnerability to subsequent stressors and lead to long-lasting cognitive deficits.

Tuesday, September 25, 2012

Male sex hormones alter the brain after exercise.

Numerous experiments have shown that exercise enhances our ability to remember and think, and causes formation of new nerve cells. A collaboration that includes McEwen's Laboratory of Neuroendocrinology at Rockefeller now shows (in rats) that brain (not gonadal) production of the testosterone derivative dihydroxtestosterone (DHT) is required for this effect. The amount of exercise required is quite mild (McEwen: "the equivalent of jogging at a pace at which someone could speak (or squeak) to a companion."). In castrated rats blocking the action of testosterone levels that have been enhanced by exercise (by blocking testosterone receptors in the brain) also blocks the formation of new nerve cells. The chemical details are given by their abstract:
Mild exercise activates hippocampal neurons through the glutamatergic pathway and also promotes adult hippocampal neurogenesis (AHN). We hypothesized that such exercise could enhance local androgen synthesis and cause AHN because hippocampal steroid synthesis is facilitated by activated neurons via N-methyl-D-aspartate receptors. Here we addressed this question using a mild-intense treadmill running model that has been shown to be a potent AHN stimulator. A mass-spectrometric analysis demonstrated that hippocampal dihydrotestosterone increased significantly, whereas testosterone levels did not increase significantly after 2 wk of treadmill running in both orchidectomized (ORX) and sham castrated (Sham) male rats. Furthermore, analysis of mRNA expression for the two isoforms of 5α-reductases (srd5a1, srd5a2) and for androgen receptor (AR) revealed that both increased in the hippocampus after exercise, even in ORX rats. All rats were injected twice with 5′-bromo-2′deoxyuridine (50 mg/kg body weight, i.p.) on the day before training. Mild exercise significantly increased AHN in both ORX and Sham rats. Moreover, the increase of doublecortin or 5′-bromo-2′deoxyuridine/NeuN-positive cells in ORX rats was blocked by s.c. flutamide, an AR antagonist. It was also found that application of an estrogen receptor antagonist, tamoxifen, did not suppress exercise-induced AHN. These results support the hypothesis that, in male animals, mild exercise enhances hippocampal synthesis of dihydrotestosterone and increases AHN via androgenenic mediation.
In commenting on this work in the NYTimes, Gretchen Reynolds raises an interesting question for women:
But while those findings may be salutary for men who are active and fit, or planning to become so, they seem potentially troubling for those of us without testes. If DHT is necessary for neurogenesis after exercise and women produce far less of it than men, do women gain less brain benefit from exercise than men?

Monday, September 24, 2012

On being nothing...

The "Opinionater" feature of the New York Times has "Anxiety" as one of its topics inviting online essays. I wanted to pass on a piece submitted by Brian Jay Stanley that notes how at every stage of our lives we desire to be noticed and affirmed by others, and in the absence of notice can easily become anxious, feeling insignificant and insubstantial. His last two paragraphs are a treat:
Society is adroit at disillusioning newcomers, and many self-assured children grow up to be bitter adults. But bitterness, instead of a form of disillusionment, is really the refusal to give up your childhood illusions of importance. Ignored instead of welcomed by the world, you fault the world as blind and evil in order not to fault yourself as naïve. Bitterness is a child’s coddling narcissism within the context of an adult’s harsh life. Instead, I know that the world only tramples me as a street crowd does an earthworm — not out of malice or stupidity, but because no one sees it. Thus my pain is not to feel wrongly slighted, but to feel rightly slighted.
There must be a Copernican revolution of the self. Instead of pointlessly cursing the sun to go around me, my chance of contentment is learning to orbit, being the world’s audience instead of demanding the world be mine. If the world is a stage, then everyone’s an extra, acting minor roles in simultaneous scenes in which no one has the lead. With so much happening, society is poorly made to satisfy pride, but well made to satisfy interest, if we will only let go of our vanity and join the swirl of activity.

Friday, September 21, 2012

Signing beforehand increases honesty.

Here is a fascinating simple study by Shu et al. Simply signing a statement of honesty at the top rather the bottom of a form makes you more honest. They outline the problem:
The annual tax gap between actual and claimed taxes due in the United States amounts to roughly $345 billion. The Internal Revenue Service estimates more than half this amount is due to individuals misrepresenting their income and deductions (1). Insurance is another domain burdened by the staggering cost of individual dishonesty; the Coalition Against Insurance Fraud estimated that the overall magnitude of insurance fraud in the United States totaled $80 billion in 2006 (2). The problem with curbing dishonesty in behaviors such as filing tax returns, submitting insurance claims, claiming business expenses or reporting billable hours is that they primarily rely on self-monitoring in lieu of external policing.
Here is their abstract:
Many written forms required by businesses and governments rely on honest reporting. Proof of honest intent is typically provided through signature at the end of, e.g., tax returns or insurance policy forms. Still, people sometimes cheat to advance their financial self-interests—at great costs to society. We test an easy-to-implement method to discourage dishonesty: signing at the beginning rather than at the end of a self-report, thereby reversing the order of the current practice. Using laboratory and field experiments, we find that signing before, rather than after, the opportunity to cheat makes ethics salient when they are needed most and significantly reduces dishonesty.
The experimental design used several different measures of cheating: self-reported earnings (income) on a math puzzles task wherein university participants could cheat for financial gain, self reported travel expenses to the laboratory (deductions) claimed on a tax return form on research earnings. Another experiment was done in the field with an insurance company in the southeastern United States asking some of their existing customers to report their odometer reading. They examined the effect of requiring the signature at the top of the form, the bottom, or the control of requiring no signature.

A personal history.

I thought I would mention that in response to several requests from friends and family I have now posted a personal history on my dericbownds.net website at http://www.dericbownds.net/DericHistory.html.

Thursday, September 20, 2012

Distinct prefrontal areas regulating cognitive control and value decisions.

A massive study involving workers at five different universities has utilized a dataset on brain lesions accumulated over many decades to reveal two distinct functional-anatomical networks within the prefrontal cortex (PFC), one associated with cognitive control and the other associated with value-based decision-making. They used lesion-symptom mapping in 344 participants who were assessed by using a large battery of standardized neuropsychological tasks. Of these participants, 165 had damage in the frontal lobes that included sectors of the PFC, supplementary motor area (SMA), or premotor cortex (PM). Here is their abstract, followed by some details:
A considerable body of previous research on the prefrontal cortex (PFC) has helped characterize the regional specificity of various cognitive functions, such as cognitive control and decision making. Here we provide definitive findings on this topic, using a neuropsychological approach that takes advantage of a unique dataset accrued over several decades. We applied voxel-based lesion-symptom mapping in 344 individuals with focal lesions (165 involving the PFC) who had been tested on a comprehensive battery of neuropsychological tasks. Two distinct functional-anatomical networks were revealed within the PFC: one associated with cognitive control (response inhibition, conflict monitoring, and switching), which included the dorsolateral prefrontal cortex and anterior cingulate cortex and a second associated with value-based decision-making, which included the orbitofrontal, ventromedial, and frontopolar cortex. Furthermore, cognitive control tasks shared a common performance factor related to set shifting that was linked to the rostral anterior cingulate cortex. By contrast, regions in the ventral PFC were required for decision-making. These findings provide detailed causal evidence for a remarkable functional-anatomical specificity in the human PFC.
Here is a description of the array of tests used (edited to simplify):
The four cognitive control tasks were as follows: the Trail-Making Test (TMT), a measure of executive response switching; the Perseverative Errors score from the Wisconsin Card Sorting Test (WCST), which measures impairments in set switching; the Color-Word Interference score from the Stroop Test (STROOP), a measure of response inhibition; and the Number of Words score from the Controlled Oral Word Association Test (COWA), which measures verbal fluency, divergent thinking, and response creativity. As an index of value-based decision-making and reward learning, we used the Net Score (advantageous minus disadvantageous choices) from the Iowa Gambling Task (IGT). All these tasks have been extensively used and well standardized, and they have been shown to detect impairments reliably in clinical populations such as ours. As expected, the cognitive control-related tasks were all weakly, but positively intercorrelated, whereas their correlation with the IGT was generally lower, a pattern that remained even after the covariates were statistically removed from the data.
And here is a summary graphic:


Results from the lesion overlap analysis of different tests of cognitive control and value-based decision making.

Wednesday, September 19, 2012

Motivation influences how time flies when you’re having fun.

Numerous studies have shown that a positive state, relative to a negative state, makes time appear to pass more quickly and causes assessments of elapsed time to be shorter. Gable and Pool examine how the degree of motivation - as distinguished from positive or negative valence (as in approach versus withdrawal) - influences subjective time:
Time flies when you’re having fun, but what is it about pleasant experiences that makes time seem to go by faster? In the experiments reported here, we tested the proposal that approach motivation causes perceptual shortening of time during pleasant experiences. A first experiment showed that, relative to a neutral state or a positive state with low approach motivation, a positive state with high approach motivation shortened perceptions of time. Also, individual differences in approach motivation predicted shorter perceptions of time. In a second experiment we manipulated approach motivation independently of the affective state and showed that increasing approach motivation caused time to be perceived as passing more quickly. Finally we showed that positive approach motivation, as opposed to arousal, shortens perception of time by comparing a highly arousing positive state with a highly arousing negative state. Shortening of time perception in appetitive states may prolong approach-motivated behavior and increase the likelihood of acquiring appetitive objects or goals.

Tuesday, September 18, 2012

Neural signature of affiliative emotions.

Moll et al. do an interesting study to experimentally disentangle affiliative experience from general emotional valence, by demonstrating that brain areas distinctive to expression of affiliative (bonding) emotions engage an ensemble of basal forebrain structures that is conserved in mammals, and can be distinguished from areas reflecting the positive or negative emotional valence that accompanies the subjective affiliative experience. Here is their abstract, following by one of the illustrations from the paper:
Comparative studies have established that a number of structures within the rostromedial basal forebrain are critical for affiliative behaviors and social attachment. Lesion and neuroimaging studies concur with the importance of these regions for attachment and the experience of affiliation in humans as well. Yet it remains obscure whether the neural bases of affiliative experiences can be differentiated from the emotional valence with which they are inextricably associated at the experiential level. Here we show, using functional MRI, that kinship-related social scenarios evocative of affiliative emotion induce septal–preoptic–anterior hypothalamic activity that cannot be explained by positive or negative emotional valence alone. Our findings suggest that a phylogenetically conserved ensemble of basal forebrain structures, especially the septohypothalamic area, may play a key role in enabling human affiliative emotion. Our finding of a neural signature of human affiliative experience bears direct implications for the neurobiological mechanisms underpinning impaired affiliative experiences and behaviors in neuropsychiatric conditions.

Figure Legend - Activation of the septal/preoptic-anterior hypothalamic and medial FPC, predicted a priori, as well as in the left posterior superior temporal sulcus region (data not shown) and precuneus (Prec), observed in the affiliative versus nonaffiliative contrast.

Figure Legend - Brain regions associated with positive versus negative conditions (red-yellow) and negative versus positive contrasts (blue-green). Activation of the ventral striatum (VStr) and medial orbitofrontal cortex (medOFC; BA11/32) was observed in the positive versus negative contrast. For the negative versus positive contrast, activation of dorsomedial prefrontal cortex (dmPFC; BA 8/9) and lateral frontal cortex, including the lateral orbitofrontal cortex and inferior frontal gyrus (latFC), as well as the adjoining anterior insula (antIns) was observed (BA 45/47/48).

Monday, September 17, 2012

Do implicit attitudes predict actual voting behavior?

How can psychologists and pollsters predict the voting behavior of undecided voters? Is there is any hope for us Obama supporters who worry about the effectiveness of the clever framing of the conservative marketing aimed at undecided voters that pushes emotional buttons with complete disregard for rationality or facts? Friese et al. show that explicit attitudes predict voting behavior better than implicit attitudes for both decided and undecided voters, while implicit attitudes predict voting behavior better for decided than undecided voters. While this is not to say that explicit attitudes can't also be based on irrationality, it does argue against the power of implicit attitudes of which the voter is unaware. Here is their abstract:
The prediction of voting behavior of undecided voters poses a challenge to psychologists and pollsters. Recently, researchers argued that implicit attitudes would predict voting behavior particularly for undecided voters whereas explicit attitudes would predict voting behavior particularly for decided voters. We tested this assumption in two studies in two countries with distinct political systems in the context of real political elections. Results revealed that (a) explicit attitudes predicted voting behavior better than implicit attitudes for both decided and undecided voters, and (b) implicit attitudes predicted voting behavior better for decided than undecided voters. We propose that greater elaboration of attitudes produces stronger convergence between implicit and explicit attitudes resulting in better predictive validity of both, and less incremental validity of implicit over explicit attitudes for the prediction of voting behavior. However, greater incremental predictive validity of implicit over explicit attitudes may be associated with less elaboration.