Monday, December 31, 2012

A usefull trick: Shifting attention to reduce emotional reactivity.

Thiruchselvam et al. do a simple demonstration of how our introspective attention can regulate our emotions after an unpleasant for fearful stimulus. Shifting the focus of that subsequent attention away from the challenging part of the image lessens emotional reactivity.  Here is their abstract, following by the basic experimental protocol:
Selective attention plays a fundamental role in emotion regulation. To date, research has examined individuals’ use of selective attention to regulate emotional responses during stimulus presentation. In the present study, we examined whether selective attention can be used to regulate emotional responses during a poststimulus period when representations are active within working memory (WM). On each trial, participants viewed either a negative or a neutral image. After the offset of the image, they maintained a representation of it in WM and were cued to focus their attention on either neutral or arousing aspects of that representation. Results showed that, relative to focusing on an arousing portion of a negative-image representation within WM, focusing on a neutral portion of the representation reduced both self-reported negative emotion and the late positive potential, a robust neural measure of emotional reactivity. These data suggest that selective attention can alter emotional responses arising from affective representations active within WM.

Figure (click to enlarge): Illustration of the trial structure. After an initial fixation period, an image (either negative or neutral) appeared on-screen for 1,500 ms. Then, two circles were overlaid on the image for 1,500 ms. For negative images (as shown here), one circle highlighted a neutral portion, whereas the other circle highlighted an arousing portion. For neutral images, both circles highlighted neutral portions. The image then disappeared, leaving a black screen for 750 ms, during which participants held the full image in working memory. Then, one of the circles was presented briefly for 250 ms. In the subsequent 3,000-ms interval, participants had to focus their attention on the portion of the image that had previously been contained within the target circle. Participants then rated how pleasant or unpleasant they felt.

Monday, December 24, 2012

Happy Holidays - a personal note - and MindBlog taking a break

My partner Len and I have traveled from our Fort Lauderdale snowbird retreat to Austin Texas to join  my ex-wife Marilyn Young, son Jonathan Bownds, daughter-in-law Shana Merlin, and my first grandchild, their new 9 month old grandson Sebastian.   They are now living in the Bownds family home that now has sheltered four generations of the Bownds family.  Daughter Sarah Bownds from Madison is also here.

Training parts of your brain for perceptual enhancement.

Geraint Rees and collaborators have done some fascinating work showing that training the spontaneous activity of just a part of our visual brain, corresponding to just a part of our visual field, can enhance the visual performance of that part of our vision:
Perception depends on the interplay of ongoing spontaneous activity and stimulus-evoked activity in sensory cortices. This raises the possibility that training ongoing spontaneous activity alone might be sufficient for enhancing perceptual sensitivity. To test this, we trained human participants to control ongoing spontaneous activity in circumscribed regions of retinotopic visual cortex using real-time functional MRI-based neurofeedback. After training, we tested participants using a new and previously untrained visual detection task that was presented at the visual field location corresponding to the trained region of visual cortex. Perceptual sensitivity was significantly enhanced only when participants who had previously learned control over ongoing activity were now exercising control and only for that region of visual cortex. Our new approach allows us to non-invasively and non-pharmacologically manipulate regionally specific brain activity and thus provide “brain training” to deliver particular perceptual enhancements.

Friday, December 21, 2012

For guys who want to attract women?

Perhaps there is a human equivalent of the non-volatile protein pheromone darcin, that Roberts et al. show to stimulate spatial preference and learning in mice. Female mice preferred locations where male urine (or synthesized darcin) had been found, and remembered these spatial locations for 2 weeks post-exposure. (Scent marking is an essential component of communication for most mammals. Individuals remember the location of scent marks and regularly revisit marked sites, presumably to assess the condition and status of the animal doing the marking. It is known that individuals can follow odor or pheromone gradients to locate another individual, but relocating scent marks is a much more difficult task given the small amount of volatile compounds deposited, and their static nature.) Here is the abstract:
Many mammals use scent marking for sexual and competitive advertisement, but little is known about the mechanism by which scents are used to locate mates and competitors. We show that darcin, an involatile protein sex pheromone in male mouse urine, can rapidly condition preference for its remembered location among females and competitor males so that animals prefer to spend time in the site even when scent is absent. Learned spatial preference is conditioned through contact with darcin in a single trial and remembered for approximately 14 days. This pheromone-induced learning allows animals to relocate sites of particular social relevance and provides proof that pheromones such as darcin can be highly potent stimuli for social learning.

Thursday, December 20, 2012

Unconscious reading and arithmetic.

Here is a fascinating bit from Sklar et al.:
The modal view in the cognitive and neural sciences holds that consciousness is necessary for abstract, symbolic, and rule-following computations. Hence, semantic processing of multiple-word expressions, and performing of abstract mathematical computations, are widely believed to require consciousness. We report a series of experiments in which we show that multiple-word verbal expressions can be processed outside conscious awareness and that multistep, effortful arithmetic equations can be solved unconsciously. All experiments used Continuous Flash Suppression to render stimuli invisible for relatively long durations (up to 2,000 ms). Where appropriate, unawareness was verified using both objective and subjective measures. The results show that novel word combinations, in the form of expressions that contain semantic violations, become conscious before expressions that do not contain semantic violations, that the more negative a verbal expression is, the more quickly it becomes conscious, and that subliminal arithmetic equations prime their results. These findings call for a significant update of our view of conscious and unconscious processes.
(note:  Continuous Flash Suppression consists of a presentation of a target stimulus to one eye and a simultaneous presentation of rapidly changing masks to the other eye. The rapidly changing masks dominate awareness until the target breaks into consciousness. This suppression may last seconds. To examine arithmetic, another symbolic, rule-following system, the authors moved from a breaking-into-consciousness design to a priming design. They examined the effects of subliminal stimuli on conscious stimuli that follow them, using both subjective and objective measures to verify the subliminality of the primes.)

Wednesday, December 19, 2012

Grin and bear it.

Kraft and Pressman make a nice observation on linking muscle movement to emotion, showing how manipulating the muscles involved in a smile can alter the stress response:
In the study reported here, we investigated whether covertly manipulating positive facial expressions would influence cardiovascular and affective responses to stress. Participants (N = 170) naive to the purpose of the study completed two different stressful tasks while holding chopsticks in their mouths in a manner that produced a Duchenne smile, a standard smile, or a neutral expression. Awareness was manipulated by explicitly asking half of all participants in the smiling groups to smile (and giving the other half no instructions related to smiling). Findings revealed that all smiling participants, regardless of whether they were aware of smiling, had lower heart rates during stress recovery than the neutral group did, with a slight advantage for those with Duchenne smiles. Participants in the smiling groups who were not explicitly asked to smile reported less of a decrease in positive affect during a stressful task than did the neutral group. These findings show that there are both physiological and psychological benefits from maintaining positive facial expressions during stress.

Tuesday, December 18, 2012

Brain plasticity induced by musical training.

As a lifelong pianist, I have always regarded with awe pianists like Horowitz and Rubenstein who have continued to perform into into their advanced old age. I have done some 4 hands recitals here in my winter nest of Fort Lauderdale with an 87-year old retired music professor and performer who still gives solo concerts. Musical performance makes very complex demands on visual, auditory, and motor processing. Numerous studies have shown that subcortical and cortical brain regions can change with musical training. Hernholz and Zatorre offer a massive review of musical training as a framework for brain plasticity in a recent issue of Neuron. I can't even begin to summarize the abundant material presented and offer only the abstract and one sample figure here (motivated readers can request a PDF of the article from me.)
Musical training has emerged as a useful framework for the investigation of training-related plasticity in the human brain. Learning to play an instrument is a highly complex task that involves the interaction of several modalities and higher-order cognitive functions and that results in behavioral, structural, and functional changes on time scales ranging from days to years. While early work focused on comparison of musical experts and novices, more recently an increasing number of controlled training studies provide clear experimental evidence for training effects. Here, we review research investigating brain plasticity induced by musical training, highlight common patterns and possible underlying mechanisms of such plasticity, and integrate these studies with findings and models for mechanisms of plasticity in other domains.

Figure 2 (click to enlarge). Interindividual Differences in Auditory Cortical Structure and Function(A) Variability in auditory cortex gray matter concentration and cortical thickness predicted performance on a melodic transposition task (adapted from Foster and Zatorre, 2010).(B) Different rates of behavioral improvement during pitch memory training were accompanied by differential training-related functional changes in secondary auditory areas (adapted from Gaab et al., 2006).(C) BOLD signal covariation to increasing pitch size in microtonal melodies prior to training in both left and right auditory cortices was predictive of the speed with which learning occurred, such that those individuals who subsequently learned more quickly had an initially steeper response function (adapted from Zatorre et al., in press).

Monday, December 17, 2012

The herding hormone

Yet another addition, from Stallen et al., to the long list of studies on oxytocin and our social behaviors (enter oxytocin in the search box in the left column to pull up the numerous mindblog posts on oxytocin effects on our behaviors):
People often conform to others with whom they associate. Surprisingly, however, little is known about the possible hormonal mechanisms that may underlie in-group conformity. Here, we examined whether conformity toward one’s in-group is altered by oxytocin, a neuropeptide often implicated in social behavior. After administration of either oxytocin or a placebo, participants were asked to provide attractiveness ratings of unfamiliar visual stimuli. While viewing each stimulus, participants were shown ratings of that stimulus provided by both in-group and out-group members. Results demonstrated that on trials in which the ratings of the in-group and out-group were incongruent, the ratings of participants given oxytocin conformed to the ratings of their in-group but not of their out-group. Participants given a placebo did not show this in-group bias. These findings indicate that administration of oxytocin can influence subjective preferences, and they support the view that oxytocin’s effects on social behavior are context dependent.

Friday, December 14, 2012

Brain imaging of the positive bias we place on social feedback.

Continuing the social brain thread started by yesterday's post, I pass on this piece by Korn et al. showing brain correlates of the rose colored glasses we put on interpreting social feedback from others. Participants in the study rated how much 40 positive and 40 negative trait adjectives applied to themselves and to one other person before and after receiving feedback ratings of themselves. The critical test for positively biased updating was finding that the changes toward desirable feedback were larger than the changes toward undesirable feedback. Here is their abstract:
Receiving social feedback such as praise or blame for one's character traits is a key component of everyday human interactions. It has been proposed that humans are positively biased when integrating social feedback into their self-concept. However, a mechanistic description of how humans process self-relevant feedback is lacking. Here, participants received feedback from peers after a real-life interaction. Participants processed feedback in a positively biased way, i.e., they changed their self-evaluations more toward desirable than toward undesirable feedback. Using functional magnetic resonance imaging we investigated two feedback components. First, the reward-related component correlated with activity in ventral striatum and in anterior cingulate cortex/medial prefrontal cortex (ACC/MPFC). Second, the comparison-related component correlated with activity in the mentalizing network, including the MPFC, the temporoparietal junction, the superior temporal sulcus, the temporal pole, and the inferior frontal gyrus. This comparison-related activity within the mentalizing system has a parsimonious interpretation, i.e., activity correlated with the differences between participants' own evaluation and feedback. Importantly, activity within the MPFC that integrated reward-related and comparison-related components predicted the self-related positive updating bias across participants offering a mechanistic account of positively biased feedback processing. Thus, theories on both reward and mentalizing are important for a better understanding of how social information is integrated into the human self-concept.

Thursday, December 13, 2012

Enhancing social ability with brain stimulation.

Social information is thought to be processed by a specific set of neural circuits often referred to as the ‘social brain’ The figure shows localization in human brains of the relevant temporo-parietal junction orbitofrontal cortex in lateral (top) and medial (bottom) views.  Santiesteban et al. now show that low levels of direct current stimulation of the temporoparietal junction region improves control of self-other representations. (The electrical stimulation is two saline-soaked surface sponge electrodes driven by a battery driven constant low current stimulator). Here is their summary, followed by the abstract:
-OFC neurons respond to social visual stimul
-OFC neurons differentiate between socially defined classes of images
-OFC neurons signal the value of social information for making decisions
-More OFC neurons convey social information than fluid reward magnitude.
Primate evolution produced an increased capacity to respond flexibly to varying social contexts as well as expansion of the prefrontal cortex [1,2]. Despite this association, how prefrontal neurons respond to social information remains virtually unknown. People with damage to their orbitofrontal cortex (OFC) struggle to recognize facial expressions [3,4], make poor social judgments [5,6], and frequently make social faux pas [7,8]. Here we test explicitly whether neurons in primate OFC signal social information and, if so, how such signals compare with responses to primary fluid rewards. We find that OFC neurons distinguish images that belong to socially defined categories, such as female perinea and faces, as well as the social dominance of those faces. These modulations signaled both how much monkeys valued these pictures and their interest in continuing to view them. Far more neurons signaled social category than signaled fluid value, despite the stronger impact of fluid reward on monkeys’ choices. These findings indicate that OFC represents both the motivational value and attentional priority of other individuals, thus contributing to both the acquisition of information about others and subsequent social decisions. Our results betray a fundamental disconnect between preferences expressed through overt choice, which were primarily driven by the desire for more fluid, and preferential neuronal processing, which favored social computations.

Wednesday, December 12, 2012

Thanks for not sharing, and tuning out...

I almost did a post last week on Roger Cohen's NYTimes 'thank you for not sharing' piece , and now he has done a followup on tuning out, so I can't resist passing on a few choice clips. From the first piece:
LET us ponder oversharing and status anxiety, the two great scourges of the modern world.
What is this compulsion to share? Sometimes, of course, it is just a mistake, the wrong button hit, or mishandling of privacy settings on Facebook. But there is a new urge to behave as if life were some global high-school reunion at which everyone has taken some horrific tell-all drug.
My theory is this. Humanity has always been hardwired to fear. That is how we survived. But the fear used to be of wild beasts prowling, the encroaching Visigoths, plague, world war. Now, in the pampered present, all that anxiety has to find a new focus. So, having searched long and hard, and helped by technology, we have come up with being anxious that our status might be falling or — the horror, the horror! — disintegrating.
Number of Twitter followers shrinking or not growing as fast as your friends’? Status anxiety attack begins. No e-mails or texts received in the past 78 minutes? Status anxiety attack accelerates. Got unfriended or discover by chance on LinkedIn that your 29-year-old college roommate is now running an agribusiness fund out of St. Louis that has assets of $47 billion and owns half of Madagascar? Status meltdown kicks in.
The only antidote, the only means to push that status up again, it seems, is to keep sharing more and more. Here I am — the posts and tweets and pix say — a being not anonymous but alive. I overshare therefore I am.
And from the second:
...we are not the first humans to believe the world has sped up and hyperconnected to a point where distance has been eliminated. Too often we confuse activity and movement with accomplishment and fulfillment. More may be gained through a pause...We tend to overstate what has changed. The fundamental instincts and urges of our natures remain constant. Social media did not invent the need to be loved or the fear of being unloved. They just revealed them in new ways...It is the culture of oversharing and status anxiety that disturbs me. And that is inseparable from the grip of social media. Facebook, Twitter can be addictive in ways that may provide brief solace but militate against respect of our deeper natures. There is too much noise, too little silence. To share, that once beautiful verb, has become an awful emotional splurge...The friend-follower conceits are brilliant marketing tools designed to play on insecurities. Who does not want more friends and more followers? Who does not feel the sleight of being unfriended or unfollowed, a settling of scores more impersonal than a duel and perhaps crueler for that?’s to doses of disconnection in 2013. Get out of the cross hairs of your devices from time to time. Drink experience unfiltered by hyperconnection. Gaze with patience. Listen through silences. Let your longings breathe...Somewhere deep inside everyone is the thing that makes them tick. The thing is it is often well hidden. The psyche builds layers of protection around people’s most vulnerable traits, which may be closely linked to their precious essence. Social media build layers of distraction from that essence.

Tuesday, December 11, 2012

Living without irony?

I've been wanting to pass on this marvelous essay by Christy Wampole, which bemoans the ironic sensibility that pervades our culture, and wonders whether there is any escape. Some clips:
For many Americans born in the 1980s and 1990s - members of Generation Y, or Millennials - particularly middle-class Caucasians, irony is the primary mode with which daily life is dealt. One need only dwell in public space, virtual or concrete, to see how pervasive this phenomenon has become…Take, for example, an ad that calls itself an ad, makes fun of its own format, and attempts to lure its target market to laugh at and with it. It pre-emptively acknowledges its own failure to accomplish anything meaningful. No attack can be set against it, as it has already conquered itself.
How did this happen? It stems in part from the belief that this generation has little to offer in terms of culture, that everything has already been done, or that serious commitment to any belief will eventually be subsumed by an opposing belief, rendering the first laughable at best and contemptible at worst. This kind of defensive living works as a pre-emptive surrender and takes the form of reaction rather than action…While we have gained some skill sets (multitasking, technological savvy), other skills have suffered: the art of conversation, the art of looking at people, the art of being seen, the art of being present. Our conduct is no longer governed by subtlety, finesse, grace and attention, all qualities more esteemed in earlier decades. Inwardness and narcissism now hold sway.
I, too, exhibit ironic tendencies. For example, I find it difficult to give sincere gifts. Instead, I often give what in the past would have been accepted only at a White Elephant gift exchange. Good for a chuckle in the moment, but worth little in the long term. Something about the responsibility of choosing a personal, meaningful gift for a friend feels too intimate, too momentous. I somehow cannot bear the thought of a friend disliking a gift I'd chosen with sincerity. The simple act of noticing my self-defensive behavior has made me think deeply about how potentially toxic ironic posturing could be.
Fundamentalists are never ironists; dictators are never ironists; people who move things in the political landscape, regardless of the sides they choose, are never ironists….Where can we find other examples of nonironic living? What does it look like? Nonironic models include very young children, elderly people, deeply religious people, people with severe mental or physical disabilities, people who have suffered, and those from economically or politically challenged places where seriousness is the governing state of mind. My friend Robert Pogue Harrison put it this way in a recent conversation: "Wherever the real imposes itself, it tends to dissipate the fogs of irony."
The ironic life is certainly a provisional answer to the problems of too much comfort, too much history and too many choices, but it is my firm conviction that this mode of living is not viable and conceals within it many social and political risks. For such a large segment of the population to forfeit its civic voice through the pattern of negation I've described is to siphon energy from the cultural reserves of the community at large. People may choose to continue hiding behind the ironic mantle, but this choice equals a surrender to commercial and political entities more than happy to act as parents for a self-infantilizing citizenry. So rather than scoffing at the hipster - a favorite hobby, especially of hipsters - determine whether the ashes of irony have settled on you as well. It takes little effort to dust them away.

Monday, December 10, 2012

Hindsight bias.

Regarding the recent presidential election, do you feel that you knew the outcome in your gut all along? Not only felt it coming, but are sure you predicted it beforehand? I did. (But, when I honestly look back, I was totally prepared for a Romney win, and ready to say I had predicted that all along...). In this recent article, Roese and Vohs do a nice dissection of this phenomenon:
Hindsight bias occurs when people feel that they “knew it all along,” that is, when they believe that an event is more predictable after it becomes known than it was before it became known. Hindsight bias embodies any combination of three aspects: memory distortion, beliefs about events’ objective likelihoods, or subjective beliefs about one’s own prediction abilities. Hindsight bias stems from (a) cognitive inputs (people selectively recall information consistent with what they now know to be true and engage in sensemaking to impose meaning on their own knowledge), (b) metacognitive inputs (the ease with which a past outcome is understood may be misattributed to its assumed prior likelihood), and (c) motivational inputs (people have a need to see the world as orderly and predictable and to avoid being blamed for problems). Consequences of hindsight bias include myopic attention to a single causal understanding of the past (to the neglect of other reasonable explanations) as well as general overconfidence in the certainty of one’s judgments. New technologies for visualizing and understanding data sets may have the unintended consequence of heightening hindsight bias, but an intervention that encourages people to consider alternative causal explanations for a given outcome can reduce hindsight bias.

Friday, December 07, 2012

We use body cues, not facial expression, to discriminate intense positive and negative emotions.

Interesting work from Aviezer et al:
The distinction between positive and negative emotions is fundamental in emotion models. Intriguingly, neurobiological work suggests shared mechanisms across positive and negative emotions. We tested whether similar overlap occurs in real-life facial expressions. During peak intensities of emotion, positive and negative situations were successfully discriminated from isolated bodies but not faces. Nevertheless, viewers perceived illusory positivity or negativity in the nondiagnostic faces when seen with bodies. To reveal the underlying mechanisms, we created compounds of intense negative faces combined with positive bodies, and vice versa. Perceived affect and mimicry of the faces shifted systematically as a function of their contextual body emotion. These findings challenge standard models of emotion expression and highlight the role of the body in expressing and perceiving emotions.

Thursday, December 06, 2012

MindBlog is trying a new brain fitness app

It has been a few years since I have reviewed brain fitness exercises of the sort claimed to enhance working memory and general intelligence (g). A new generation of Apps has appeared, and one - CogniFit Brain Fitness for the iPhone and iPad - gets a brief review in the iPhone App Review. The price is right (It's free), and here is a brief clip from the review: mind games in the form of visual puzzles are presented for free to each user; such games include jigsaw puzzles, mahjong, “words birds,” and “whack a mole.” Specific skills are tested during each game. For example, the jigsaw challenges are designed to hone users’ updating, focusing, and visual scanning skills while “whack a mole” is built to improve cognitive skills such as divided attention, working memory, planning, and spatial perception. While each game in this app focuses on providing different challenges, all of the games are similar in the way that they increase in difficulty as a player advances through the various levels.
I've put the App on my iPhone and iPad, and will be curious to see whether I get hooked on it. I certainly faded fast on my brief flirtation with N-back game Apps several years ago. I would welcome comments from readers who have tried the CogniFit product.

Wednesday, December 05, 2012

New Love, a short shelf life...

Lyubomirsky previews her forthcoming book “The Myths of Happiness: What Should Make You Happy, but Doesn’t, What Shouldn’t Make You Happy, but Does.” A few clips:
American and European researchers tracked 1,761 people who got married and stayed married over the course of 15 years. The findings from this and other similar studies have been clear: newlyweds enjoy a big happiness boost that lasts, on average, for just two years…then they are back where they started…new love seems nearly as vulnerable to hedonic adaptation as a new job, a new home, a new coat and other novel sources of pleasure and well-being. (Though the thrill of a new material acquisition generally fades faster.)
Sexual passion and arousal are particularly prone to hedonic adaptation…both men and women are less aroused after they have repeatedly viewed the same erotic pictures or engaged in similar sexual fantasies. Familiarity may or may not breed contempt; but research suggests that it breeds indifference … There are evolutionary, physiological and practical reasons passionate love is unlikely to endure for long. If we obsessed, endlessly, about our partners and had sex with them multiple times a day — every day — we would not be very productive at work or attentive to our children, our friends or our health…Indeed, the condition of being in love has a lot in common with the state of addiction and narcissism; if unabated, it will eventually exact a toll.
WHY, then, is the natural shift from passionate to companionate love often such a letdown? Because, although we may not realize it, we are biologically hard-wired to crave variety. Variety and novelty affect the brain in much the same way that drugs do — that is, they trigger activity that involves the neurotransmitter dopamine, as do pharmacological highs...Evolutionary biologists believe that sexual variety is adaptive, and that it evolved to prevent incest and inbreeding in ancestral environments. The idea is that when our spouse becomes as familiar to us as a sibling — when we’ve become family — we cease to be sexually attracted to each other.

Tuesday, December 04, 2012

Honesty requires time (and lack of justifications)

Here is a nice little piece from Eldar and Bereby-Meyer:
Recent research suggests that refraining from cheating in tempting situations requires self-control, which indicates that serving self-interest is an automatic tendency. However, evidence also suggests that people cheat to the extent that they can justify their unethical behavior to themselves. To merge these different lines of research, we adopted a dual-system approach that distinguished between the intuitive and deliberative cognitive systems. We suggest that for people to restrict their dishonest behavior, they need to have enough time and no justifications for self-serving unethical behavior. We employed an anonymous die-under-cup task in which participants privately rolled a die and reported the outcome to determine their pay. We manipulated the time available for participants to report their outcome (short vs. ample). The results of two experiments support our prediction, revealing that the dark side of people’s automatic self-serving tendency may be overcome when time to decide is ample and private justifications for dishonesty are not available.

Monday, December 03, 2012

Brain regions that predict and regulate risk-taking.

Two recent pieces of work raise the prospect of being able to predict and even regulate a person's risk-taking behavior, by first observing activity of the anterior cingulate cortex and then dialing it up or down.

First, Rudorf et al. show that behavioral risk preferences are reflected in the passive evaluation of risky situations:
"Individual risk preferences have a large influence on decisions, such as financial investments, career and health choices, or gambling. Decision making under risk has been studied both behaviorally and on a neural level. It remains unclear, however, how risk attitudes are encoded and integrated with choice. Here, we investigate how risk preferences are reflected in neural regions known to process risk. We collected functional magnetic resonance images of 56 human subjects during a gambling task (Preuschoff et al., 2006). Subjects were grouped into risk averters and risk seekers according to the risk preferences they revealed in a separate lottery task. We found that during the anticipation of high-risk gambles, risk averters show stronger responses in ventral striatum and anterior insula compared to risk seekers. In addition, risk prediction error signals in anterior insula, inferior frontal gyrus, and anterior cingulate indicate that risk averters do not dissociate properly between gambles that are more or less risky than expected. We suggest this may result in a general overestimation of prospective risk and lead to risk avoidance behavior. This is the first study to show that behavioral risk preferences are reflected in the passive evaluation of risky situations. The results have implications on public policies in the financial and health domain."
Figure: Anticipation risk coding. Neural activation in bilateral ventral striatum (vStr; top) and anterior insula (aIns; bottom) during anticipation of the second card that correlates with anticipation risk, i.e., expected outcome variance.
Second, Ishii et al. show (in mice) that inactivating anterior insular cortex suppresses risk-taking behavior:
"We often have to make risky decisions between alternatives with outcomes that can be better or worse than the outcomes of safer alternatives. Although previous studies have implicated various brain regions in risky decision making, it remains unknown which regions are crucial for balancing whether to take a risk or play it safe. Here, we focused on the anterior insular cortex (AIC), the causal involvement of which in risky decision making is still unclear, although human imaging studies have reported AIC activation in various gambling tasks. We investigated the effects of temporarily inactivating the AIC on rats' risk preference in two types of gambling tasks, one in which risk arose in reward amount and one in which it arose in reward delay. As a control within the same subjects, we inactivated the adjacent orbitofrontal cortex (OFC), which is well known to affect risk preference. In both gambling tasks, AIC inactivation decreased risk preference whereas OFC inactivation increased it. In risk-free control situations, AIC and OFC inactivations did not affect decision making. These results suggest that the AIC is causally involved in risky decision making and promotes risk taking. The AIC and OFC may be crucial for the opposing motives of whether to take a risk or avoid it."

Friday, November 30, 2012

Where our brains predict romantic attraction at a glance.

From Cooper et al:
Humans frequently make real-world decisions based on rapid evaluations of minimal information; for example, should we talk to an attractive stranger at a party? Little is known, however, about how the brain makes rapid evaluations with real and immediate social consequences. To address this question, we scanned participants with functional magnetic resonance imaging (fMRI) while they viewed photos of individuals that they subsequently met at real-life “speed-dating” events. Neural activity in two areas of dorsomedial prefrontal cortex (DMPFC), paracingulate cortex, and rostromedial prefrontal cortex (RMPFC) was predictive of whether each individual would be ultimately pursued for a romantic relationship or rejected. Activity in these areas was attributable to two distinct components of romantic evaluation: either consensus judgments about physical beauty (paracingulate cortex) or individualized preferences based on a partner's perceived personality (RMPFC). These data identify novel computational roles for these regions of the DMPFC in even very rapid social evaluations. Even a first glance, then, can accurately predict romantic desire, but that glance involves a mix of physical and psychological judgments that depend on specific regions of DMPFC.

Neural predictors of subsequent decision compared with areas mediating judgments of physical attractiveness. A, Brain regions showing greater responses at the time of first viewing for faces of individuals that are subsequently (after speed dating) selected as a potential romantic partner (“pursued”), compared with those who were not (“rejected”). Paracingulate cortex (circled) is the only activated region that significantly independently correlates with subsequent decision in a multiple regression including all activated regions. B, Brain regions positively correlating with subjective ratings of physical attractiveness for each partner (Att). C, Overlap between brain regions related to decision and those related to attractiveness, showing substantial overlap between these variables in the paracingulate cortex. Color bars indicate t statistic. Coordinates in ICBM/MNI space.

Thursday, November 29, 2012

Cognitive and Emotional plasticity increased by Mindfulness training

Here is a fascinating study from Allen et al:
Mindfulness meditation is a set of attention-based, regulatory, and self-inquiry training regimes. Although the impact of mindfulness training (MT) on self-regulation is well established, the neural mechanisms supporting such plasticity are poorly understood. MT is thought to act through interoceptive salience and attentional control mechanisms, but until now conflicting evidence from behavioral and neural measures renders difficult distinguishing their respective roles. To resolve this question we conducted a fully randomized 6 week longitudinal trial of MT, explicitly controlling for cognitive and treatment effects with an active-control group. We measured behavioral metacognition and whole-brain blood oxygenation level-dependent (BOLD) signals using functional MRI during an affective Stroop task before and after intervention in healthy human subjects. Although both groups improved significantly on a response-inhibition task, only the MT group showed reduced affective Stroop conflict. Moreover, the MT group displayed greater dorsolateral prefrontal cortex responses during executive processing, consistent with increased recruitment of top-down mechanisms to resolve conflict. In contrast, we did not observe overall group-by-time interactions on negative affect-related reaction times or BOLD responses. However, only participants with the greatest amount of MT practice showed improvements in response inhibition and increased recruitment of dorsal anterior cingulate cortex, medial prefrontal cortex, and right anterior insula during negative valence processing. Our findings highlight the importance of active control in MT research, indicate unique neural mechanisms for progressive stages of mindfulness training, and suggest that optimal application of MT may differ depending on context, contrary to a one-size-fits-all approach.

Wednesday, November 28, 2012

Face to face dialog is different.

Jiang et al do a neat bit of work showing how modern hi-tech dialog devices fail to engage the evolved brain and body synchronization that accompanies face-to-face dialog.
Although the human brain may have evolutionarily adapted to face-to-face communication, other modes of communication, e.g., telephone and e-mail, increasingly dominate our modern daily life. This study examined the neural difference between face-to-face communication and other types of communication by simultaneously measuring two brains using a hyperscanning approach. The results showed a significant increase in the neural synchronization in the left inferior frontal cortex during a face-to-face dialog between partners but none during a back-to-back dialog, a face-to-face monologue, or a back-to-back monologue. Moreover, the neural synchronization between partners during the face-to-face dialog resulted primarily from the direct interactions between the partners, including multimodal sensory information integration and turn-taking behavior. The communicating behavior during the face-to-face dialog could be predicted accurately based on the neural synchronization level. These results suggest that face-to-face communication, particularly dialog, has special neural features that other types of communication do not have and that the neural synchronization between partners may underlie successful face-to-face communication.

Tuesday, November 27, 2012

Body-Mind dualism - effects on health.

Forstmann et al do an interesting bit of work whose results make a lot of sense:
Beliefs in mind-body dualism—that is, perceiving one’s mind and body as two distinct entities—are evident in virtually all human cultures. Despite their prevalence, surprisingly little is known about the psychological implications of holding such beliefs. In the research reported here, we investigated the relationship between dualistic beliefs and health behaviors. We theorized that holding dualistic beliefs leads people to perceive their body as a mere “shell” and, thus, to neglect it. Supporting this hypothesis, our results showed that participants who were primed with dualism reported less engagement in healthy behaviors and less positive attitudes toward such behaviors than did participants primed with physicalism. Additionally, we investigated the bidirectionality of this link. Activating health-related concepts affected participants’ subsequently reported metaphysical beliefs in mind-body dualism. A final set of studies demonstrated that participants primed with dualism make real-life decisions that may ultimately compromise their physical health (e.g., consuming unhealthy food). These findings have potential implications for health interventions.

Monday, November 26, 2012

Oxytocin nudges men to monogamy?

Scheele et al. show that oxytocin nasal spray causes married, but not single, men to keep a greater distance from attractive woman during a first encounter. They totally should do this experiment with gay married males!
In humans, interpersonal romantic attraction and the subsequent development of monogamous pair-bonds is substantially predicted by influential impressions formed during first encounters. The prosocial neuropeptide oxytocin (OXT) has been identified as a key facilitator of both interpersonal attraction and the formation of parental attachment. However, whether OXT contributes to the maintenance of monogamous bonds after they have been formed is unclear. In this randomized placebo-controlled trial, we provide the first behavioral evidence that the intranasal administration of OXT stimulates men in a monogamous relationship, but not single ones, to keep a much greater distance (∼10–15 cm) between themselves and an attractive woman during a first encounter. This avoidance of close personal proximity occurred in the physical presence of female but not male experimenters and was independent of gaze direction and whether the female experimenter or the subject was moving. We further confirmed this unexpected finding using a photograph-based approach/avoidance task that showed again that OXT only stimulated men in a monogamous relationship to approach pictures of attractive women more slowly. Importantly, these changes cannot be attributed to OXT altering the attitude of monogamous men toward attractive women or their judgments of and arousal by pictures of them. Together, our results suggest that where OXT release is stimulated during a monogamous relationship, it may additionally promote its maintenance by making men avoid signaling romantic interest to other women through close-approach behavior during social encounters. In this way, OXT may help to promote fidelity within monogamous human relationships.

Friday, November 23, 2012

Musical protolanguage hypothesis - support from congenital amusia.

Fascinating work from Thompson et al. (open access), suggesting that sensitivity to emotion in speech prosody derives from our capacity to process music, supporting the idea of an evolutionary link between musical and language domains in the brain.:
A number of evolutionary theories assume that music and language have a common origin as an emotional protolanguage that remains evident in overlapping functions and shared neural circuitry. The most basic prediction of this hypothesis is that sensitivity to emotion in speech prosody derives from the capacity to process music. We examined sensitivity to emotion in speech prosody in a sample of individuals with congenital amusia, a neurodevelopmental disorder characterized by deficits in processing acoustic and structural attributes of music. Twelve individuals with congenital amusia and 12 matched control participants judged the emotional expressions of 96 spoken phrases. Phrases were semantically neutral but prosodic cues (tone of voice) communicated each of six emotional states: happy, tender, afraid, irritated, sad, and no emotion. Congenitally amusic individuals were significantly worse than matched controls at decoding emotional prosody, with decoding rates for some emotions up to 20% lower than that of matched controls. They also reported difficulty understanding emotional prosody in their daily lives, suggesting some awareness of this deficit. The findings support speculations that music and language share mechanisms that trigger emotional responses to acoustic attributes, as predicted by theories that propose a common evolutionary link between these domains.

Thursday, November 22, 2012

Inspired by distraction.

Baird et al. do a simple experiment demonstrating how mind wandering can facilitate creative incubation, that the basement stuff that is dinking around in the absence focused effort more easily makes novel associations:
Although anecdotes that creative thoughts often arise when one is engaged in an unrelated train of thought date back thousands of years, empirical research has not yet investigated this potentially critical source of inspiration. We used an incubation paradigm to assess whether performance on validated creativity problems (the Unusual Uses Task, or UUT) can be facilitated by engaging in either a demanding task or an undemanding task that maximizes mind wandering. Compared with engaging in a demanding task, rest, or no break, engaging in an undemanding task during an incubation period led to substantial improvements in performance on previously encountered problems. Critically, the context that improved performance after the incubation period was associated with higher levels of mind wandering but not with a greater number of explicitly directed thoughts about the UUT. These data suggest that engaging in simple external tasks that allow the mind to wander may facilitate creative problem solving.

Wednesday, November 21, 2012

Unpredictable love.

There's a nice pieces in the "Gray Matter" series in the New York Times by Richard Friedman that argues that it is our evolved motivational machinery (that drives us to seek unpredictable rewards - i.e., transient reinforcement) more strenuously than predictable ones, that underlies the fickleness of love.
Shakespeare warned women that “men were deceivers ever; one foot in sea and one on shore, to one thing constant never.” commonly people complain that they love someone who always disappoints them...This kind of amorous attachment is like gambling — except that the currency is affection and sex. The key is that the reward is unanticipated, which makes it particularly powerful and alluring to our brains.
Many experiments have shown, in both animals and humans, that intermittent rewards cause more activation and dopamine release in the brain's reward circuits than predictable rewards.
The brain’s reward circuit has evolved over millions of years to enable us to recognize and extract various rewards from our environment that are critical to our survival, like food and a suitable sexual mate. Unlike predictable stimuli, unanticipated stimuli can tell us things about the world that we don’t yet know. And because they serve as a signal that a big reward might be close by, it is advantageous that novel stimuli command our attention.
The article centers on the work of psychiatrist Gregory Berns:
One of the curious things that Professor Berns found was that most of his subjects couldn’t tell the difference between the predictable or unpredictable condition in which the reward was given...Since unpredictable rewards cause more dopamine release than predictable ones and more dopamine means more pleasure, one implication of this study is that people experience more pleasure with unpredictable rewards than with predictable ones — but they may not be consciously aware of this fact...Not just that, but there was essentially no relationship between the subjects’ stated preferences and the observed activity in their reward circuit. This suggests that our reward pathways may not only be activated without our recognition, but perhaps even in ways that are contrary to what we think we prefer...These data might explain, in part, the paradox of people who complain constantly about their unreliable lovers, but keep coming back to them, time and again.

Tuesday, November 20, 2012

The force of affective norms - the stranger effect

Szczurek et al. make a more distanced and structured description of an experience we all have had - being put on guard in a chat with another person if their facial expressions and body language do not appropriately mirror or complement our own:
What happens when affective displays deviate from normative expectations? In this study, participants evaluated target individuals displaying flat, incongruent, or congruent expressions seemingly in response to pictures eliciting positive, neutral, or negative affect. Relative to targets who displayed normative reactions, those who violated affective norms (affective deviants) were rated more negatively on various dimensions of social judgment. Participants also preferred greater social distance from affective deviants, reported more moral outrage in response to them, and inferred that these targets did not share their moral values. Incongruent affect resulted in more negative social judgment than did flat affect, and this relationship was moderated by stimulus valence. Finally, the relationship between targets’ affective expressions and participants’ avoidant intentions was mediated by the extent to which participants thought the targets shared their moral values. These findings demonstrate the interpersonal costs of affective deviance, revealing the pervasiveness and force of affective norms.

Monday, November 19, 2012

How a simple innate bias might guide visual learning

For years computer programmers have been trying to design algorithms that even remotely approach the ability of young infants in their first few months of life to rapidly learn to recognize complex objects and events in the their visual input, particularly events like hand movements and gaze direction. Even the most powerful probabilistic learning models, as well as connectionist and dynamical models, do not result by themselves in automatically learning about hands, detecting them, paying attention to what they are doing, and using them to make inferences and predictions. Ullman et al. develop a model that incorporates a plausible innate or early acquired bias, based on cognitive and perceptual findings, to detect “mover” events. It leads to the automatic acquisition of increasingly complex concepts and capabilities, which do not emerge without domain-specific biases. After exposure to video sequences containing people performing everyday actions, and without supervision, the model develops the capacity to locate hands in complex configurations by their appearance and by surrounding context and to detect direction of gaze. Here is their abstract:
Early in development, infants learn to solve visual problems that are highly challenging for current computational methods. We present a model that deals with two fundamental problems in which the gap between computational difficulty and infant learning is particularly striking: learning to recognize hands and learning to recognize gaze direction. The model is shown a stream of natural videos and learns without any supervision to detect human hands by appearance and by context, as well as direction of gaze, in complex natural scenes. The algorithm is guided by an empirically motivated innate mechanism—the detection of “mover” events in dynamic images, which are the events of a moving image region causing a stationary region to move or change after contact. Mover events provide an internal teaching signal, which is shown to be more effective than alternative cues and sufficient for the efficient acquisition of hand and gaze representations. The implications go beyond the specific tasks, by showing how domain-specific “proto concepts” can guide the system to acquire meaningful concepts, which are significant to the observer but statistically inconspicuous in the sensory input.

Friday, November 16, 2012

Carbs and self control.

From Molden et al. suggest the increase in self control that some studies have correlated with carbohydrate consumption is caused not by a metabolic energy boost, but rather by an increase in motivation:
Self-control is critical for achievement and well-being. However, people’s capacity for self-control is limited and becomes depleted through use. One prominent explanation for this depletion posits that self-control consumes energy through carbohydrate metabolization, which further suggests that ingesting carbohydrates improves self-control. Some evidence has supported this energy model, but because of its broad implications for efforts to improve self-control, we reevaluated the role of carbohydrates in self-control processes. In four experiments, we found that (a) exerting self-control did not increase carbohydrate metabolization, as assessed with highly precise measurements of blood glucose levels under carefully standardized conditions; (b) rinsing one’s mouth with, but not ingesting, carbohydrate solutions immediately bolstered self-control; and (c) carbohydrate rinsing did not increase blood glucose. These findings challenge metabolic explanations for the role of carbohydrates in self-control depletion; we therefore propose an alternative motivational model for these and other previously observed effects of carbohydrates on self-control.

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.