Friday, April 30, 2010

Evaluating effects of genes and environment on early reading.

Work from Taylor et al. studying mono- and dizygotic twins in kindergarten through 5th grade suggests, not suprisingly, that that better teachers allow children to fulfill their genetic potential:

Children’s reading achievement is influenced by genetics as well as by family and school environments. The importance of teacher quality as a specific school environmental influence on reading achievement is unknown. We studied first- and second-grade students in Florida from schools representing diverse environments. Comparison of monozygotic and dizygotic twins, differentiating genetic similarities of 100% and 50%, provided an estimate of genetic variance in reading achievement. Teacher quality was measured by how much reading gain the non-twin classmates achieved. The magnitude of genetic variance associated with twins’ oral reading fluency increased as the quality of their teacher increased. In circumstances where the teachers are all excellent, the variability in student reading achievement may appear to be largely due to genetics. However, poor teaching impedes the ability of children to reach their potential.

Thursday, April 29, 2010

When do human groups form states?

Spencer suggests that human states evolve (without contact with any preexisting states) when the area controlled by a group becomes larger than a day's round trip from the capital:

A major research problem in anthropology is the origin of the state and its bureaucratic form of governance. Of particular importance for evaluating theories of state origins are cases of primary state formation, whereby a first-generation state evolves without contact with any preexisting states. A general model of this process, the territorial-expansion model, is presented and assessed with archaeological data from six areas where primary states emerged in antiquity: Mesoamerica, Peru, Egypt, Mesopotamia, the Indus Valley, and China. In each case, the evidence shows a close correspondence in time between the first appearance of state institutions and the earliest expansion of the state's political-economic control to regions lying more than a day's round-trip from the capital. Although additional research will add detail and clarity to the empirical record, the results to date are consistent with the territorial-expansion model, which argues that the success of such long-distance expansion not only demanded the bureaucratization of central authority but also helped provide the resources necessary to underwrite this administrative transformation.

Wednesday, April 28, 2010

Do brain training programs work?

ScienceNow reports an interesting tussle over the effectiveness of brain training programs. BBC producers contacted Adrian Owen at the MRC Cognition and Brain Sciences Unit in Cambridge, U.K., to help design an experiment to test the efficacy of computer brain training exercises and tested them in 11,430 healthy adults who registered on a Web site set up by the BBC. One group trained on a program that emphasized reasoning and problem-solving skills, and another group trained on a program that emphasized different skills, including short-term memory and attention. A third, control group, essentially did busywork, hunting for answers to general knowledge questions on the Internet. All participants were asked to "train" for at least 10 minutes, three times a week for 6 weeks, and all received a battery of cognitive tests before and after this 6-week period....Not surprisingly, people in both training groups got better at the tasks they actually practiced. But that's as far as it went - none of the brain-training tasks transferred to other mental or cognitive abilities beyond what had been specifically practiced.

These conclusion are contested by Klingberg, who has published one of the few studies demonstrating benefits of training can generalize beyond a specific task. He notes subjects were trained only three hours in total.

I'm a bit puzzled over why the work of Jaeggi et al. showing the effects of short term memory training on general intelligence, which I have mentioned previously, was not mentioned.

Tuesday, April 27, 2010

Old age improves reasoning about social conflicts

Interesting observation from Grossmann et al.:

It is well documented that aging is associated with cognitive declines in many domains. Yet it is a common lay belief that some aspects of thinking improve into old age. Specifically, older people are believed to show better competencies for reasoning about social dilemmas and conflicts. Moreover, the idea of aging-related gains in wisdom is consistent with views of the aging mind in developmental psychology. However, to date research has provided little evidence corroborating this assumption. We addressed this question in two studies, using a representative community sample. We asked participants to read stories about intergroup conflicts and interpersonal conflicts and predict how these conflicts would unfold. We show that relative to young and middle-aged people, older people make more use of higher-order reasoning schemes that emphasize the need for multiple perspectives, allow for compromise, and recognize the limits of knowledge. Our coding scheme was validated by a group of professional counselors and wisdom researchers. Social reasoning improves with age despite a decline in fluid intelligence. The results suggest that it might be advisable to assign older individuals to key social roles involving legal decisions, counseling, and intergroup negotiations. Furthermore, given the abundance of research on negative effects of aging, this study may help to encourage clinicians to emphasize the inherent strengths associated with aging.

Monday, April 26, 2010

Internet enhancing, not diminishing, the public square.

Some interesting points from David Brooks, noting a study by Gentzkow and Shapiro which counters the prevailing assumption that the internet has created a collection of information cocoons which people occupy to confirm their existing prejudices:

...they tracked how people of different political views move around the Web...The study measures the people who visit sites, not the content inside...a person who visited only Fox News would have more overlap with conservatives than 99 percent of Internet news users. A person who only went to The Times’s site would have more liberal overlap than 95 percent of users....the core finding is that most Internet users do not stay within their communities. Most people spend a lot of time on a few giant sites with politically integrated audiences, like Yahoo News.

But even when they leave these integrated sites, they often go into areas where most visitors are not like themselves. People who spend a lot of time on Glenn Beck’s Web site are more likely to visit The New York Times’s Web site than average Internet users. People who spend time on the most liberal sites are more likely to go to foxnews.com than average Internet users. Even white supremacists and neo-Nazis travel far and wide across the Web....Gentzkow and Shapiro found that the Internet is actually more ideologically integrated than old-fashioned forms of face-to-face association — like meeting people at work, at church or through community groups. You’re more likely to overlap with political opponents online than in your own neighborhood.

...Looking at a site says nothing about how you process it or the character of attention you bring to it. It could be people spend a lot of time at their home sites and then go off on forays looking for things to hate. But it probably does mean they are not insecure and they are not sheltered....If this study is correct, the Internet will not produce a cocooned public square, but a free-wheeling multilayered Mad Max public square. The study also suggests that if there is increased polarization (and there is), it’s probably not the Internet that’s causing it.

How pain impairs cognition

Ji et al. use an animal model of arthritis pain to show that pain-related cognitive deficits result from amygdala-driven impairment of medial prefrontal cortical (mPFC) function.

Friday, April 23, 2010

Oxytocin enhances social learning as well as empathy.

From Hurlemann et al.:

Oxytocin (OT) is becoming increasingly established as a prosocial neuropeptide in humans with therapeutic potential in treatment of social, cognitive, and mood disorders. However, the potential of OT as a general facilitator of human learning and empathy is unclear. The current double-blind experiments on healthy adult male volunteers investigated first whether treatment with intranasal OT enhanced learning performance on a feedback-guided item–category association task where either social (smiling and angry faces) or nonsocial (green and red lights) reinforcers were used, and second whether it increased either cognitive or emotional empathy measured by the Multifaceted Empathy Test. Further experiments investigated whether OT-sensitive behavioral components required a normal functional amygdala. Results in control groups showed that learning performance was improved when social rather than nonsocial reinforcement was used. Intranasal OT potentiated this social reinforcement advantage and greatly increased emotional, but not cognitive, empathy in response to both positive and negative valence stimuli. Interestingly, after OT treatment, emotional empathy responses in men were raised to levels similar to those found in untreated women. Two patients with selective bilateral damage to the amygdala (monozygotic twins with congenital Urbach–Wiethe disease) were impaired on both OT-sensitive aspects of these learning and empathy tasks, but performed normally on nonsocially reinforced learning and cognitive empathy. Overall these findings provide the first demonstration that OT can facilitate amygdala-dependent, socially reinforced learning and emotional empathy in men.

Thursday, April 22, 2010

The brain's default mode, our ego, and Freud

Carhart-Harris and Friston offer an open access article exploring the notion that Freudian constructs may have neurobiological substrates.

Specifically, we propose that Freud’s descriptions of the primary and secondary processes are consistent with self-organized activity in hierarchical cortical systems and that his descriptions of the ego are consistent with the functions of the default-mode and its reciprocal exchanges with subordinate brain systems. This neurobiological account rests on a view of the brain as a hierarchical inference or Helmholtz machine. In this view, large-scale intrinsic networks occupy supraordinate levels of hierarchical brain systems that try to optimize their representation of the sensorium. This optimization has been formulated as minimizing a free-energy; a process that is formally similar to the treatment of energy in Freudian formulations. We substantiate this synthesis by showing that Freud’s descriptions of the primary process are consistent with the phenomenology and neurophysiology of rapid eye movement sleep, the early and acute psychotic state, the aura of temporal lobe epilepsy and hallucinogenic drug states.

The best illusion of the year contest

The top ten candidates for the 2010 best Illusion of the Year context have been chosen. The site show the illusions from previous years' competitions.

Wednesday, April 21, 2010

Doing two things at once splits the brain.

...and we are not very good at managing more than two things at once. Here is the fascinating abstract from Charron and Koechlin:

The anterior prefrontal cortex (APC) confers on humans the ability to simultaneously pursue several goals. How does the brain’s motivational system, including the medial frontal cortex (MFC), drive the pursuit of concurrent goals? Using brain imaging, we observed that the left and right MFC, which jointly drive single-task performance according to expected rewards, divide under dual-task conditions: While the left MFC encodes the rewards driving one task, the right MFC concurrently encodes those driving the other task. The same dichotomy was observed in the lateral frontal cortex, whereas the APC combined the rewards driving both tasks. The two frontal lobes thus divide for representing simultaneously two concurrent goals coordinated by the APC. The human frontal function seems limited to driving the pursuit of two concurrent goals simultaneously.
A figure from the ScienceNow review. When tackling tasks A and B simultaneously, half of the brain handles A (red) while the other handles B (yellow).

Opera singers' brains - and the brain's organization of music knowledge

Numerous studies have shown brain changes that correlate with athletic and musical instrument training. Kleber et al. now extend such work to vocal performance training:

Several studies have shown that motor-skill training over extended time periods results in reorganization of neural networks and changes in brain morphology. Yet, little is known about training-induced adaptive changes in the vocal system, which is largely subserved by intrinsic reflex mechanisms. We investigated highly accomplished opera singers, conservatory level vocal students, and laymen during overt singing of an Italian aria in a neuroimaging experiment. We provide the first evidence that the training of vocal skills is accompanied by increased functional activation of bilateral primary somatosensory cortex representing articulators and larynx. Opera singers showed additional activation in right primary sensorimotor cortex. Further training-related activation comprised the inferior parietal lobe and bilateral dorsolateral prefrontal cortex. At the subcortical level, expert singers showed increased activation in the basal ganglia, the thalamus, and the cerebellum. A regression analysis of functional activation with accumulated singing practice confirmed that vocal skills training correlates with increased activity of a cortical network for enhanced kinesthetic motor control and sensorimotor guidance together with increased involvement of implicit motor memory areas at the subcortical and cerebellar level. Our findings may have ramifications for both voice rehabilitation and deliberate practice of other implicit motor skills that require interoception.
In another article on the brain and music, Omar et al. (open access) compare normal subjects with alzheimer's and dementia patients to find evidence that music knowledge is fractionated, with superordinate musical knowledge relatively more robust than knowledge of particular music. They propose that music constitutes a distinct domain of non-verbal knowledge but shares certain cognitive organizational features with other brain knowledge systems. Within the domain of music knowledge, dissociable cognitive mechanisms process knowledge derived from physical sources and the knowledge of abstract musical entities.

Tuesday, April 20, 2010

PharmVille

An article by Virginia Heffernan in the NYTimes Sunday Magazine points to the interesting Psych-Babble website hosted by psychiatry professor Robert Hsiung at the University of Chicago.

Hsiung’s F.A.Q. includes a section called, “How should I decide what information to trust?” Compiled entirely from board posts, it’s a masterpiece. Above all, it empowers Web users and psychiatric patients alike to be strong readers, to mediate between dictatorial commercial culture and the radical factionalism and individualism of Web communities. One answer came from a poster called Daveman: “The search for truth reminds me of Hegel. It is neither the ‘thesis’ (the claim by the manufacturer that the medication is some sort of wonder drug) nor the ‘antithesis’ (the claim by someone who blames all their problems on the medication) but rather a ‘synthesis’ (a sober analysis of both positive and negative aspects).” Very sanely put.
The article also points to an online cognitive behavioral therapy site, and the Icarus Project, investigating "the space between brilliance and madness."

Enhanced facial threat detection in elite warriors

Ross et al show that Navy SEALS, compared with a male control group, show more focused neural and performance tuning: greater neural processing resources are directed toward threat stimuli (angry faces), while processing resources are conserved when facing a nonthreatening stimul (fearful or happy faces).

Irrespective of the target emotion, elite warfighters relative to comparison subjects showed relatively greater right-sided insula, but attenuated left-sided insula, activation. Navy SEALs showed selectively greater activation to angry target faces relative to fearful or happy target faces bilaterally in the insula. This was not accounted for by contrasting positive versus negative emotions. Finally, these individuals also showed slower response latencies to fearful and happy target faces than did comparison subjects.

Monday, April 19, 2010

MindBlog's spring home

This picture (click to enlarge) of early spring at my 1860 stone schoolhouse residence in Middleton Wisconsin shows why I recently returned from  winter exile in Fort Lauderdale (which doesn't have seasons). 

Two routes to slowing aging...

Fontana et al. offer a nice article in the April 16 issue of Science Magazine, a review of experiments indicating that caloric restriction and reduced activity of nutrient-sensing pathways may slow aging by similar mechanisms. I am passing on the excellent summary of the article's main points provided by the magazine, as well as the final section of the article on the outlook for the future (well worth a look for resveratrol enthusiasts.  A previous mindblog post on resveratrol side effect has drawn multiple comments):

Nutrient-sensing pathways are central to the aging process
Both dietary restriction -- a reduction of food intake without malnutrition -- and manipulation of nutrient-sensing pathways through mutations or drugs can increase life span and reduce age-related disease in several model organisms. These pathways are conserved during evolution.

Single-celled yeast provides a simple model system for studying aging
The life span of yeast can be increased substantially through both dietary restriction and mutation or drugs. Reduced activity in two major nutrient-sensing pathways is involved.

C. elegans worms are a simple multicellular model system for aging
Life-span increases in C. elegans are similar to those in yeast. As in yeast, aging in C. elegans is delayed by the activation of pathways normally turned on by starvation/food restriction.

Flies provide a more complex model system that allows e.g. sex differences to be studied
The damage response pathways in some unicellular eukaryotes, such as yeast, differ from those in mammals. Their telomeres are tailored to respond to these differences. The way in which telomeres solve the end protection problem thus differs widely between eukaryotes.

Studies of rodents may yield leads for human clinical trials
Both dietary restriction and manipulation of nutrient-sensing pathways through mutation or drugs can reduce the occurrence of age-related diseases and extend life span in rodents. However, dietary restriction in rodents can also have negative effects. Differences in metabolism, life span, and susceptibility to diseases must be taken into account when extrapolating these results to humans.

Limited data exist on life-span extension in primates
Naturally occurring mutations in humans or monkeys help to understand the role of nutrient-sensing pathways in aging. Experimental studies are complicated by the long life spans of primates. The protective effects of dietary restriction against cancer, cardiovascular disease, and diabetes in primates must be weighed against potentially negative long term effects.

A key question is how we can extend the life span without unwanted side effects
The identification of a common set of genes in yeast, worms, flies, and mice that can extend the healthy life span will accelerate progress toward human clinical trials testing drugs that activate these conserved anti-aging pathways. Further mammalian studies are needed to understand whether dietary restriction and the pharmacological modulation of anti-aging pathways can extend life span and reduce pathologies.

Outlook
Extreme dietary restriction can lead to several detrimental health effects such as amenorrhea, infertility, sarcopenia, osteoporosis, and immune deficiencies. Thus, it will be important to examine these negative side-effects in dietary-restricted subjects that are not malnourished. Indeed, experimental studies are required to evaluate the optimal calorie intake and macro- and micronutrient composition needed for healthy aging in humans, on the basis of age, sex, genotype, and energy expenditure.

Although adjustment of dietary intake and composition may be realistic and beneficial, the severe dietary restriction that induces major health benefits is not a desirable option for most people. Drugs that target nutrient-sensing pathways to obtain the health benefits of dietary restriction are realistic, but the effects of chronic administration require study. For instance, rapamycin, the TOR (target of rapamycin) inhibitor that extends mouse life span, is an immunosuppressant and may not produce an overall health benefit in humans living in an environment with pathogens. However, genetic deletion of the GH receptor or of the downstream S6 kinase in mice extends life span and induces a broad-spectrum improvement in health. More testing of potential disadvantages is required and many open questions remain, but these seem promising drug targets and are hopefully the first of many.

Friday, April 16, 2010

More detail on money and happiness

Yet another study, this one by Boyce et al. (open access), confirming that money doesn't buy happiness, people gain "utility" from occupying a higher ranked position within an income distribution rather than from either absolute income or their position relative to a reference wage:

Does money buy happiness, or does happiness come indirectly from the higher rank in society that money brings? We tested a rank-income hypothesis, according to which people gain utility from the ranked position of their income within a comparison group. The rank hypothesis contrasts with traditional reference-income hypotheses, which suggest that utility from income depends on comparison to a social reference-group norm. We found that the ranked position of an individual’s income predicts general life satisfaction, whereas absolute income and reference income have no effect. Furthermore, individuals weight upward comparisons more heavily than downward comparisons. According to the rank hypothesis, income and utility are not directly linked: Increasing an individual’s income will increase his or her utility only if ranked position also increases and will necessarily reduce the utility of others who will lose rank.

Thursday, April 15, 2010

Like humans - Leaders, Followers and Schmoozers among animals

Natalie Angier does an interesting article describing work showing that the array of personality types noted within human groups, mostly likely largely due to genetic variation, is seen also in many animal populations (stylistic diversity is seen in chimpanzees, monkeys, barnacle geese, farm minks, blue tits and great tits, bighorn sheep, dumpling squid, pumpkinseed sunfish, zebra finches, spotted hyenas, even spiders and water striders, to name a few). A particular robust parallel is noted with variation in the traits of neophobia (fear of novelty) versus the willingness to explore one’s surroundings (The trait distinctive to birds leading a flock is apparently boldness). Field experiments with birds have now answered the critique that observing these distinct traits in different individuals might be due to the captive environment of laboratory behavioral studies. Researchers have identified:
...hotheads and tiptoers, schmoozers and loners, divas, dullards and fearless explorers.. animals, like us, often cling to the same personality for the bulk of their lives...highly sensitive, arty-type humans have a lot in common with squealing pigs and twitchy mice, and that to call a hypersensitive person thin-skinned or touchy might hold a grain of physical truth.

Wednesday, April 14, 2010

Self control without a self...

The fact that humans are better at self control (delayed gratification) than animals is often attributed to their having a sense of self that animal lack. Simple body chemistry also appears to play a role. Miller et al. point to a regulator of self control that is common to humans and dogs: blood glucose. Here is their abstract:

Self-control constitutes a fundamental aspect of human nature. Yet there is reason to believe that human and nonhuman self-control processes rely on the same biological mechanism—the availability of glucose in the bloodstream. Two experiments tested this hypothesis by examining the effect of available blood glucose on the ability of dogs to exert self-control. Experiment 1 showed that dogs that were required to exert self-control on an initial task persisted for a shorter time on a subsequent unsolvable task than did dogs that were not previously required to exert self-control. Experiment 2 demonstrated that providing dogs with a boost of glucose eliminated the negative effects of prior exertion of self-control on persistence; this finding parallels a similar effect in humans. These findings provide the first evidence that self-control relies on the same limited energy resource among humans and nonhumans. Our results have broad implications for the study of self-control processes in human and nonhuman species.

Tuesday, April 13, 2010

Lessening moral judgements by a magenetic zap to the brain.

MRI measurements have shown that the the right temporoparietal junction (RTPJ) - an area just above the right ear - receives more blood than usual when we think or read about the beliefs and intentions of other people, particularly if we use the information to judge people negatively. Young et al. show that this area is actually involved in making negative moral judgements, because when it is inactivated by trans cranial magnetic stimulation (TMS), subjects judge an attempted versus an accidental homicide less severely. The abstract:

When we judge an action as morally right or wrong, we rely on our capacity to infer the actor's mental states (e.g., beliefs, intentions). Here, we test the hypothesis that the right temporoparietal junction (RTPJ), an area involved in mental state reasoning, is necessary for making moral judgments. In two experiments, we used transcranial magnetic stimulation (TMS) to disrupt neural activity in the RTPJ transiently before moral judgment...and during moral judgment... In both experiments, TMS to the RTPJ led participants to rely less on the actor's mental states. A particularly striking effect occurred for attempted harms (e.g., actors who intended but failed to do harm): Relative to TMS to a control site, TMS to the RTPJ caused participants to judge attempted harms as less morally forbidden and more morally permissible. Thus, interfering with activity in the RTPJ disrupts the capacity to use mental states in moral judgment, especially in the case of attempted harms.

Monday, April 12, 2010

We separate identity and emotion of a stimulus in under 100 msec.

Liu and Ioannides record the small rapid magnetic signals caused by brain activity (using magnetoencephalography, or MEG) to study whether face affect recognition depends on where the face stimulus (happy, fearful, neutral) appears in the visual field. Emotional appraisal (amygdalar activity) occurs more rapidly than final cognitive appraisal in the pre-frontal cortex - (We jump away from a moving S-shaped figure in our peripheral vision before we have determined whether it is actually a snake). Here is their abstract:

It is now apparent that the visual system reacts to stimuli very fast, with many brain areas activated within 100 ms. It is, however, unclear how much detail is extracted about stimulus properties in the early stages of visual processing. Here, using magnetoencephalography we show that the visual system separates different facial expressions of emotion well within 100 ms after image onset, and that this separation is processed differently depending on where in the visual field the stimulus is presented. Seven right-handed males participated in a face affect recognition experiment in which they viewed happy, fearful and neutral faces. Blocks of images were shown either at the center or in one of the four quadrants of the visual field. For centrally presented faces, the emotions were separated fast, first in the right superior temporal sulcus (STS; 35–48 ms), followed by the right amygdala (57–64 ms) and medial pre-frontal cortex (83–96 ms). For faces presented in the periphery, the emotions were separated first in the ipsilateral amygdala and contralateral STS. We conclude that amygdala and STS likely play a different role in early visual processing, recruiting distinct neural networks for action: the amygdala alerts sub-cortical centers for appropriate autonomic system response for fight or flight decisions, while the STS facilitates more cognitive appraisal of situations and links appropriate cortical sites together. It is then likely that different problems may arise when either network fails to initiate or function properly.

Friday, April 09, 2010

Brain correlates of anticipation and body dysmorphic disorder

For readers who like this sort of stuff, this post is a grab-bag pointing to three recent studies correlating brain activity with behavior, two on anticipation and one on body dysmorphic disorder:

A group at University College London finds that the temporal probability of expected visual events is encoded not by a single area but by a wide network that importantly includes neuronal populations at the very earliest cortical stages of visual processing. Activity in those areas changes dynamically in a manner that closely accords with temporal expectations. (These early stages have generally been thought to be locked to the visual stimulus in an invariant and automatic way. Now they appear to link with higher parietal and motor-related areas known to be involved in anticipation.)

Kahnt et al. show that reward value of sensory cues can be decoded from distributed fMRI patterns in the orbitofrontal cortex, and that value representations in the orbitofronal cortex are independent of whether reward is anticipated or actually received.

Finally, a study from UCLA in the Archives of General Psychiatry finds that subjects with body dysmorphic disorder (i.e., preoccupied with perceived defects in their appearance) show (compared with control subjects) hyperactivity in the left orbitofrontal cortex and bilateral head of the caudate when viewing their own face versus a familiar face. This suggests abnormalities in visual processing and frontostriatal systems in body dysmorphic disorder. The two most effective theraputic approaches to the disorder are cognitive behavioral therapy and treatment with serotonin-enhancing drugs, either alone or in combination. As Brody notes, what does not work is plastic surgery and other cosmetic treatments. Even if the treatments modify one presumed defect, the person is likely to come up with another, and another, and another, leading to a vicious cycle of costly and often deforming as well as ineffective remedies.

Thursday, April 08, 2010

fMRI measurents distinguish specific memories

It was bound to happen at some point - given the rapid refinement of fMRI measurement and analysis over the past few years. Eleanor Maguire and her colleagues at University College London report in Current Biology that different episodic memories can be distinguished as they are recalled. In their experiments fMRI signals from the hippocampus were measured as volunteers observed and were asked to memorize different 7-second movie clips. A computer algorithm was used to match the pattern of activity to each memory. When subjects were subsequently instructed to recall one of the movie clips, the algorithm performed much better than chance at determining which movie was being recalled. Their results show that highly abstracted representations of space are expressed across tens of thousands of coordinated neurons in our hippocampus in a structured manner. They suggest that, contrary to current consensus, neuronal ensembles representing place memories must be large and have an anisotropic structure.

Wednesday, April 07, 2010

April stirs the dull roots...and MindBlog is on the road.

Today I start my annual migration from Fort Lauderdale (the Winter home) back to Middleton, Wisconsin (the Spring, Summer, and Fall home) - driving with my two Abyssinian cats. A few posts are in the queue to appear, but after that MindBlog postings may be lean or absent for a few days...

Early spring pictures of our Wisconsin home sent by my partner Len show why I return (Florida doesn't have seasons). 

Unconscious control of 'conscious' prefrontal cognitive control.

Unconscious information has been shown to influence motivation, reward value and decision making, emotional processing, object recognition, semantic processing, and action planning/execution. Van Gaal et al. now look for evidence of unconscious cognitive control. From their text and the abstract:

Cognitive control becomes necessary when routine behavior (e.g., driving a car) is interrupted unexpectedly by information (e.g., a 'no-go' stimulus such as a pedestrian crossing the street) that calls for behavioral adaptations (e.g., braking fiercely). Generally speaking, it is thought that one should be conscious of the control-initiating stimulus to implement control and to overcome or to inhibit automatized ongoing behavior ("to regain control"). The recruitment and implementation of such control processes depend strongly on the prefrontal cortex (PFC), which is, of all brain regions, also the one most often associated with conscious experience. Therefore, it seems likely that consciousness and cognitive control are intimately related and this belief is so strong that many authors naturally refer to the concept of "conscious cognitive control" as if "unconscious cognitive control" is inconceivable.

We used functional magnetic resonance imaging to investigate to what extent unconscious "no-go" stimuli are capable of reaching cortical areas involved in inhibitory control, particularly the inferior frontal cortex (IFC) and the pre-supplementary motor area (pre-SMA). Participants performed a go/no-go task that included conscious (weakly masked) no-go trials, unconscious (strongly masked) no-go trials, as well as go trials. Replicating typical neuroimaging findings, response inhibition on conscious no-go stimuli was associated with a (mostly right-lateralized) frontoparietal "inhibition network." Here, we demonstrate, however, that an unconscious no-go stimulus also can activate prefrontal control networks, most prominently the IFC and the pre-SMA. Moreover, if it does so, it brings about a substantial slowdown in the speed of responding, as if participants attempted to inhibit their response but just failed to withhold it completely. Interestingly, overall activation in this "unconscious inhibition network" correlated positively with the amount of slowdown triggered by unconscious no-go stimuli. In addition, neural differences between conscious and unconscious control are revealed. These results expand our understanding of the limits and depths of unconscious information processing in the human brain and demonstrate that prefrontal cognitive control functions are not exclusively influenced by conscious information.


Figure - Neural activation associated with unconsciously triggered no-go inhibition. The contrast between responded, strongly masked no-go trials and responded, strongly masked go trials revealed significant activation in three a priori hypothesized regions of interest (pre-SMA and left/right IFC).

Tuesday, April 06, 2010

The love that dare not squawk its name.

Various forms of same-sex sexual activity, some of them long term couplings, have been recorded in more than 450 different species of animals by now, "from flamingos to bison to beetles to guppies to warthogs." Jon Mooallem does an interesting article on the topic, whose title is used as the title of this post, in this past Sunday's NY Times Magazine. A few clips, which don't do justice to the breadth of the article:
“There is still an overall presumption of heterosexuality,” the biologist Bruce Bagemihl told me. “Individuals, populations or species are considered to be entirely heterosexual until proven otherwise.” While this may sound like a reasonable starting point, Bagemihl calls it a “heterosexist bias” and has shown it to be a significant roadblock to understanding the diversity of what animals actually do. In 1999, Baghemihl published “Biological Exuberance,” a book that pulled together a colossal amount of previous piecemeal research and showed how biologists’ biases had marginalized animal homosexuality for the last 150 years — sometimes innocently enough, sometimes in an eruption of anthropomorphic disgust. Courtship behaviors between two animals of the same sex were persistently described in the literature as “mock” or “pseudo” courtship — or just “practice.” Homosexual sex between ostriches was interpreted by one scientist as “a nuisance” that “goes on and on.” One man, studying Mazarine Blue butterflies in Morocco in 1987, regretted having to report “the lurid details of declining moral standards and of horrific sexual offenses” which are “all too often packed” into national newspapers. And a bighorn-sheep biologist confessed in his memoir, “I still cringe at the memory of seeing old D-ram mount S-ram repeatedly.” To think, he wrote, “of those magnificent beasts as ‘queers’ — Oh, God!”

Different ideas are emerging about how these behaviors could fit within that traditional Darwinian framework, including seeing them as conferring reproductive advantages in roundabout ways...a single explanation of homosexual behavior in animals may not be possible, because thinking of “homosexual behavior in animals” as a single scientific subject might not make much sense...the point of heterosexual sex...no matter what kind of animal is doing it, is primarily reproduction. But that shouldn’t trick us into thinking that homosexual behavior has some equivalent, organizing purpose.

What animals do — what’s perceived to be “natural” — seems to carry a strange moral potency: it’s out there, irrefutably, as either a validation or a denunciation of our own behavior, depending on how you happen to feel about homosexuality and about nature. During the Victorian era, observations of same-sex behavior in swans and insects were held up as evidence against the morality of homosexuality in humans, since at the dawn of industrialism and Darwinism, people were invested in seeing themselves as more civilized than the “lower animals.” Robert Mugabe and the Nazis have employed the same reasoning, as did the 1970s anti-gay crusader Anita Bryant, who, Bruce Bagemihl notes, claimed in an interview that “even barnyard animals don’t do what homosexuals do” and was unmoved when the interviewer pointed out what actually happens in barnyards. On the other hand, an Australian drag queen known as Dr. Gertrude Glossip has used Bagemihl’s book to create a celebratory, interpretive gay animal tour of the Adelaide zoo, marketed to gay and lesbian tourists. The book has also been cited in a 2003 Supreme Court case that overturned a Texas state ban on sodomy and, similarly, in a legislative debate on the floor of the British Parliament.

James Esseks, director of the Lesbian, Gay, Bisexual and Transgender Project at the American Civil Liberties Union, told me he has never incorporated facts about animal behavior into a legal argument about the rights of human beings. It’s totally beside the point, he said; people should not be discriminated against regardless of what animals do. (In her book, “Sexual Selections,” Marlene Zuk writes, “People need to be able to make decisions about their lives without worrying about keeping up with the bonobos.”) That being said, Esseks told me, polls show that Americans are more likely to discriminate against gays and lesbians if they think homosexuality is “a choice.” “It shouldn’t be the basis of a moral judgment,” he said. But sometimes it is, and gay animals are compelling evidence that being gay isn’t a choice at all. In fact, Esseks remembers reading a brief mention of animal homosexual behavior during an anthropology class in college in the mid-’80s. “And as a closeted guy, it made a difference to me,” he told me. He remembers thinking: “Oh, hey, this is quote-unquote natural. This is normal. This is part of the normal spectrum of humanity — or life.”

Monday, April 05, 2010

A new wave in literary studies - theories of mind

Patricia Cohen writes an article on a new trend in the musty hallways of university English departments,  trying to unite cognitive psychology and literary criticism.  Here are some slightly edited clips:

Why do we read fiction? Why do we care so passionately about nonexistent characters? What underlying mental processes are activated when we read? ...The layered process of figuring out what someone else is thinking — of mind reading — is both a common literary device and an essential survival skill. This capacity is termed 'theory of mind' by cognitive psychologists.

Humans can comfortably keep track of three different mental states at a time. For example, the proposition “Peter said that Paul believed that Mary liked chocolate” is not too hard to follow. Add a fourth level, though, and it’s suddenly more difficult. And experiments have shown that at the fifth level understanding drops off by 60 percent. Modernist authors like Virginia Woolf are especially challenging because she asks readers to keep up with six different mental states, or levels of intentionality...Perhaps the human facility with three levels is related to the intrigues of sexual mating. Do I think he is attracted to her or me?
Experiments are actually planned to perform MRI experiments on subjects exposed to a set of texts of graduated complexity, noting brain areas previously associated with theory of mind operations. Cohen's article notes nother perspective:
...fictional accounts help explain how altruism evolved despite our selfish genes. Fictional heroes are [frequently] “altruistic punishers,” people who right wrongs even if they personally have nothing to gain. “To give us an incentive to monitor and ensure cooperation, nature endows us with a pleasing sense of outrage” at cheaters, and delight when they are punished. We enjoy fiction because it is teeming with altruistic punishers: Odysseus, Don Quixote, Hamlet, Hercule Poirot...It’s not just that evolution gives us insight into fiction, but also that fiction gives us insight into evolution.

Friday, April 02, 2010

A Mozart presto

Final movement of the Mozart from Monday and Wednesday.

Blocking the emotions of old memories.

Dolan and collaborators do an interesting study showing that beta-adrenergic blockers (which are known to block the initial storage of emotions along with declarative memory of an event) can later also strip away the emotional memories associated with an event during its recall, an effect which persists for at least 24 hours in the absence of the blocker . The abstract:

Memory enhancement for emotional events is dependent on amygdala activation and noradrenergic modulation during learning. A potential role for noradrenaline (NE) during retrieval of emotional memory is less well understood. Here, we report that administration of the β-adrenergic receptor antagonist propranolol at retrieval abolishes a declarative memory enhancement for emotional items. Critically, this effect persists at a subsequent 24 h memory test, in the absence of propranolol. Thus, these findings extend our current understanding of the role of NE in emotional memory to encompass effects at retrieval, and provide face validity to clinical interventions using β-adrenergic antagonists in conjunction with reactivation of unwanted memories in anxiety-related disorders.

Thursday, April 01, 2010

Mate preferences predicted by national health.

DeBruine et al have done an interesting study in which 4500 women from 30 different countries in Europe and the Americas went to a Web site (faceresearch.org) and noted their preferences between pairs of 20 different white male faces, some of them digitally manipulated to increase or decrease masculine features. They wanted to test the evolutionary psychology suggestion that women may prefer tough-looking guys because their offspring are more likely to survive. (The downside is that manly men tend not to be the best dads, investing fewer resources in their offspring.) The less healthy a woman's country was, the more likely she was to prefer the masculinized faces. Those at the high end of the macho-preferring scale came from Brazil, also ranked as having the worst health. Those who tended more toward the girly men were from Belgium and Sweden, the healthiest. Here is their abstract:

Recent formulations of sexual selection theory emphasize how mate choice can be affected by environmental factors, such as predation risk and resource quality. Women vary greatly in the extent to which they prefer male masculinity and this variation is hypothesized to reflect differences in how women resolve the trade-off between the costs (e.g. low investment) and benefits (e.g. healthy offspring) associated with choosing a masculine partner. A strong prediction of this trade-off theory is that women's masculinity preferences will be stronger in cultures where poor health is particularly harmful to survival. We investigated the relationship between women's preferences for male facial masculinity and a health index derived from World Health Organization statistics for mortality rates, life expectancies and the impact of communicable disease. Across 30 countries, masculinity preference increased as health decreased. This relationship was independent of cross-cultural differences in wealth or women's mating strategies. These findings show non-arbitrary cross-cultural differences in facial attractiveness judgements and demonstrate the use of trade-off theory for investigating cross-cultural variation in women's mate preferences.

Facilitating choice with a electrical zap to the head

Hecht et al. show that a 2 milliamp direct current from a battery (small and safe, but noticeable to subjects) passed between one saline-soaked surface sponge electrode placed on the head over the left dorsolateral prefrontal cortex (anodal, positive) and another over the right dorsolateral prefrontal cortex (cathodal, negative) causes participants to become quicker in selecting the most frequent alternative in a probabilistic guessing task, suggesting a cognitive facilitation in reasoning and decision-making processes.  Here is their abstract:

In a random sequence of binary events where one alternative occurs more often than the other, humans tend to guess which of the two alternatives will occur next by trying to match the frequencies of previous occurrences. Based on split-brain and unilaterally damaged patients' performances, it has been proposed that the left hemisphere (LH) tends to match the frequencies, while the right hemisphere (RH) tends toward maximizing and always choosing the most frequent alternative. The current study used transcranial direct current stimulation (tDCS) to test this hemispheric asymmetry hypothesis by stimulating the dorsolateral prefrontal cortex of each hemisphere and simultaneously inhibiting the corresponding region in the homotopic hemisphere, while participants were engaged in a probabilistic guessing task. Results showed no difference in strategy between the three groups (RH anodal/LH cathodal, LH anodal/RH cathodal, no stimulation) as participants predominantly matched the frequencies of the two alternatives. However, when anodal tDCS was applied to the LH and cathodal tDCS applied to the RH, participants became quicker to select the most frequent alternative. This finding is in line with previous evidence on the involvement of the LH in probabilistic learning and reasoning and adds to a number of demonstrations of anodal tDCS leading to some behavioral enhancement or change in bias.