Dopamine receptor genes and independent versus interdependent social orientation.

Kitayama et al. make yet another stab at finding correlates of the often cited distinction of European American (more independent) and Asians (more interdependent). Their suggested genetic correlate can be compared with the environmental correlate I just noted in a recent post. Here, with the usual 'correlations are not causes' disclaimer, is their abstract:

Prior research suggests that cultural groups vary on an overarching dimension of independent versus interdependent social orientation, with European Americans being more independent, or less interdependent, than Asians. Drawing on recent evidence suggesting that the dopamine D4 receptor gene (DRD4) plays a role in modulating cultural learning, we predicted that carriers of DRD4 polymorphisms linked to increased dopamine signaling (7- or 2-repeat alleles) would show higher levels of culturally dominant social orientations, compared with noncarriers. European Americans and Asian-born Asians (total N = 398) reported their social orientation on multiple scales. They were also genotyped for DRD4. As in earlier work, European Americans were more independent, and Asian-born Asians more interdependent. This cultural difference was significantly more pronounced for carriers of the 7- or 2-repeat alleles than for noncarriers. Indeed, no cultural difference was apparent among the noncarriers. Implications for potential coevolution of genes and culture are discussed.

Given that the independent/interdependent ratio is a consequence of gene-cultural environment interaction, it is possible that some cultural effects might be moderated by specific dopamine receptor genetic variants. (Other work has suggested different alleles of the serotonin transporter gene correlate with susceptibility to stress and depression, and that serotonin 1A receptor gene polymorphism correlates with cultural difference in holistic attention.)

Speed reading apps blow away comprehension.

Schotter et al. make a demonstration that being able to glance back during reading (not allowed under speed reading conditions) significantly enhances comprehension...readers' control over their eye movements is important.

Recent Web apps have spurred excitement around the prospect of achieving speed reading by eliminating eye movements (i.e., with rapid serial visual presentation, or RSVP, in which words are presented briefly one at a time and sequentially). Our experiment using a novel trailing-mask paradigm contradicts these claims. Subjects read normally or while the display of text was manipulated such that each word was masked once the reader’s eyes moved past it. This manipulation created a scenario similar to RSVP: The reader could read each word only once; regressions (i.e., rereadings of words), which are a natural part of the reading process, were functionally eliminated. Crucially, the inability to regress affected comprehension negatively. Furthermore, this effect was not confined to ambiguous sentences. These data suggest that regressions contribute to the ability to understand what one has read and call into question the viability of speed-reading apps that eliminate eye movements (e.g., those that use RSVP).

Watching the physical correlate of memory improvement during sleep.

Euston and Steenland do a perspective on nice work by Yang et al. that probes the role of sleep in altering mouse brain structures. I pass on their summary figure (click to enlarge) and some context comments.:

Figure Legend. Three phenomena that occur during sleep have been linked to memory enhancement—slow-wave oscillations in brain electrical activity, reactivation of recent experiences, and changes in synaptic connectivity but the strength of the evidence (indicated by arrow thickness) varies. As shown in red, Yang et al. link both reactivation and slow-wave sleep to changes in synaptic connectivity that enhance learning.

To address whether synaptic strength increases or decreases during sleep, Yang et al. used a powerful technique to visualize dendritic spines in the motor cortex of live mice. The mice were genetically engineered to express a fluorescent protein in a subset of cortical cells. A small window was created in the skull, allowing microscopic imaging of dendritic spines repeatedly over the course of hours or even days. This technique was previously used to show that training mice to stay atop a rotating rod—an acquired skill—induced the formation of new dendritic spines in the motor cortex. Further, the rate of new spine formation was correlated with the degree of task improvement. These findings provided direct evidence that synaptic change in the mammalian cortex underlies learning. Yang et al. extend these findings, showing that learning-induced spine changes are segregated on specific dendritic branches. After learning, when two branches on the same dendritic arbor were examined, one typically showed many more new spines than the other. If mice were subsequently trained on a different skill (i.e., running backward on the spinning rod), the new spines induced by the second task grew selectively on the previously underproductive branch. Hence, different skills seem to be localized on different dendritic branches.

To test the role of sleep in spine formation, Yang et al. repeated their experiment with and without an 8-hour period of sleep deprivation immediately after training. Sleep deprivation markedly decreased the number of new spines. This effect also was branch-specific in that sleep deprivation reduced spine formation primarily on the dendritic branch with the higher number of new spines. Importantly, sleep had no effect on the rate of spine elimination. The authors also observed that sleep made newly formed spines much more likely to still be present 1 day later, consistent with the idea that consolidated memories are less sensitive to decay. In other words, sleep gives spines staying power.

When being a control-freak doesn't help....

Bocanegra and Hommel note limits to the usefulness of cognitive control, showing, in particular, how overcontrol (induced by task instructions) can prevent the otherwise automatic exploitation of statistical stimulus characteristics needed to optimize behavior. They describe how they set up the experiment:

Participants performed a two-alternative forced-choice task on a foveally presented stimulus that could vary on a subset of binary perceptual features, such as color (red, green), shape (diamond, square), size (large, small), topology (open, closed), and location (up, down). Unbeknownst to the participants, we manipulated the statistical informativeness of an additional feature that was not part of the task, such that this feature always predicted the correct response in one condition (the predictive condition) but not in the other condition (the baseline condition). Because the cognitive system is known to exploit statistical stimulus-response contingencies automatically, performance was expected to be better in the predictive than in the baseline condition.

We embedded these predictive and baseline conditions into two different tasks, which we thought would induce different cognitive-control states. The control task included instructions intended to emphasize the need for top-down control: Participants were instructed to classify the stimulus according to a feature-conjunction rule (e.g., size and topology: left response key for large and open or small and closed shapes, right response key for small and open or large and closed shapes). The automatic task included instructions intended to deemphasize the need for control: Participants were instructed to classify the stimulus according to a single feature (e.g., shape: left response key for a diamond and right response key for a square). In the automatic task, the features were mapped consistently on responses and thus allowed automatic visuomotor translation. In contrast, the stimulus-response mapping in the control task required the attention-demanding integration of two features before the response could be determined.

As expected, the predictive feature improved performance when participants performed the task automatically. Counterintuitively, however, the predictive feature impaired performance when subjects were performing the exact same task in a top-down, controlled manner.

Their abstract:

In order to engage in goal-directed behavior, cognitive agents have to control the processing of task-relevant features in their environments. Although cognitive control is critical for performance in unpredictable task environments, it is currently unknown how it affects performance in highly structured and predictable environments. In the present study, we showed that, counterintuitively, top-down control can impair and interfere with the otherwise automatic integration of statistical information in a predictable task environment, and it can render behavior less efficient than it would have been without the attempt to control the flow of information. In other words, less can sometimes be more (in terms of cognitive control), especially if the environment provides sufficient information for the cognitive system to behave on autopilot based on automatic processes alone.

Another Poulenc offering: Improvisation No. 13

Another Monday morning post of a recent piano recording I've done.

  

Brain initiative meets physics….Opps!

Scientists leading the much-heralded Obama Brain Initiative initially providing $100 million (now NIH is seeking 4.5 billion for their part of the project) to craft new tools for measuring brain activity may have been insufficiently aware that some of their ideas:

“violated either a physical law or some very significant engineering constraint or biological constraint,”

I want to pass on the text of this article noting a meeting sponsored by the National Science Foundation at Cold Spring Harbor Laboratory.

The goal is to have a realistic discussion of what the physical limits are, he says, so “scientists who want to make devices will not make crazy proposals,” or, “if a proposal is crazy, one could recognize it as such” and look for other ways to make the idea work.

One such “fanciful” idea is to build nanosized radios that could snuggle up to individual neurons to record and transmit information about their activity, says physicist Peter Littlewood, director of Argonne National Laboratory in Lemont, Illinois. But any radio small enough to be injected into the brain without causing significant harm would not be able to transmit any information out through tissue and bone, he says. Make the devices any more powerful, he adds, and they'd likely cook the surrounding brain. Another aspiration that is likely doomed is to get microscopes that probe the brain with pulses of light to penetrate much further than they already do, Mitra says. A little more than 1 mm is possible, he adds, but even 1 cm is “out of the question, since the signal to background [noise] ratio decreases exponentially with depth.”

But physicists and engineers shouldn't simply shoot down outlandish proposals—or gripe about the intrinsic messiness of the brain's biology. They should model themselves as “fancy technicians” who can help develop revolutionary tools, Littlewood says. There are precedents for such collaboration, he notes: He, Mitra, and their colleagues at Bell Labs, for example, helped develop functional magnetic resonance imaging in the 1990s.

One area where physical scientists can help today is in fashioning small, strong, conductive wires that can record from many different neurons simultaneously, says neuro physicist David Kleinfeld of the University of California, San Diego. For decades, neuro scientists have relied largely on electrodes fashioned from fragile glass pipettes. But only a small number of these sensors will fit in a given brain region without disrupting connections between cells or killing them outright. Biophysicist Timothy Harris at the Janelia Farm Research Campus in Ashburn, Virginia, and others have had some success at making much smaller ones for fish and fly brains—some, made of silicon, are roughly 3 microns wide, about 25 times thinner than a human hair.

These probes are by no means the tiniest possible—polymer-coated carbon nanotubes, for example, can be 0.1 microns or smaller across and are highly conductive. Such thin wires tend to be very short and too flexible to get into the brain easily, however—when pushed, they simply buckle. One question Harris plans to pose at the meeting is whether the probes could be magnetized, then pulled, rather than pushed, into the brain with a powerful magnet.

Ultimately, researchers hope to measure neural activity inside the brain without poking wires into living tissue, and there, too, physics can help. Harris has his eye on light-sheet microscopy, which shines a plane of light across a living brain tissue, illuminating neurons engineered to fluoresce green or red when they are flooded by calcium during neuronal firing. Last year, neuroscientist Misha Ahrens and colleagues at Janelia Farm used this technique to produce the first “real” whole-brain activity map of a zebrafish larva, Harris says.

A larval zebrafish brain is 1000 times smaller than a mouse brain, however. It is also conveniently transparent, while mouse and human brain tissue scatter and blur light. Using the same optical techniques that astronomers employ to discern very faint or close-together stars with a telescope, researchers such as physicist Na Ji, also at Janelia Farm, have discovered ways to distinguish between hard-to-see neurons in murky brain tissue.

In preparation for the meeting, Mitra has brushed off an old copy of Principles of Optics by Emil Wolf and Max Born, one of the most venerable and difficult physics tomes. Getting back to basics, he hopes, will help him and his BRAIN project colleagues determine which rules must be followed to the letter, and which might be cleverly circumvented.

Gratitude reduces economic impatience.

Whenever I come across yet another self-help laundry list of useful tricks for feeling better, and try a few, I repeatedly find that briefly following instructions to practice feeling gratitude has a very salutary, calming, effect...taking the edge off any impatience I might be feeling. DeSteno et al. look at this in a more systematic way, distinguishing the effect of gratitude from more positive global emotions of happiness with respect impatience, or short-term gratification. 75 study participants were split in three groups with different emotion-induction conditions: being asked to write brief essays on experiences of feeling grateful, happy, or neutral. They then made choices between receiving smaller cash amounts (ranging from $11 to $80) immediately and larger cash amounts (ranging from $25 to $85) at a point from 1 week to 6 months in the future. Their results clearly revealed that gratitude reduces excessive economic impatience (the temporal discounting of future versus immediate rewards) compared with the neutral and happy conditions, which were about equal. Here is their abstract:

The human mind tends to excessively discount the value of delayed rewards relative to immediate ones, and it is thought that “hot” affective processes drive desires for short-term gratification. Supporting this view, recent findings demonstrate that sadness exacerbates financial impatience even when the sadness is unrelated to the economic decision at hand. Such findings might reinforce the view that emotions must always be suppressed to combat impatience. But if emotions serve adaptive functions, then certain emotions might be capable of reducing excessive impatience for delayed rewards. We found evidence supporting this alternative view. Specifically, we found that (a) the emotion gratitude reduces impatience even when real money is at stake, and (b) the effects of gratitude are differentiable from those of the more general positive state of happiness. These findings challenge the view that individuals must tamp down affective responses through effortful self-regulation to reach more patient and adaptive economic decisions.

Childhood bullying predicts adult inflammation.

How is this for a chilling finding? Childhood bullying leaves bullies with lower, and victims with higher, levels of chronic inflammation than those uninvolved in bullying. From Copeland et al. :

Bullying is a common childhood experience that involves repeated mistreatment to improve or maintain one’s status. Victims display long-term social, psychological, and health consequences, whereas bullies display minimal ill effects. The aim of this study is to test how this adverse social experience is biologically embedded to affect short- or long-term levels of C-reactive protein (CRP), a marker of low-grade systemic inflammation. The prospective population-based Great Smoky Mountains Study (n = 1,420), with up to nine waves of data per subject, was used, covering childhood/adolescence (ages 9–16) and young adulthood (ages 19 and 21). Structured interviews were used to assess bullying involvement and relevant covariates at all childhood/adolescent observations. Blood spots were collected at each observation and assayed for CRP levels. During childhood and adolescence, the number of waves at which the child was bullied predicted increasing levels of CRP. Although CRP levels rose for all participants from childhood into adulthood, being bullied predicted greater increases in CRP levels, whereas bullying others predicted lower increases in CRP compared with those uninvolved in bullying. This pattern was robust, controlling for body mass index, substance use, physical and mental health status, and exposures to other childhood psychosocial adversities. A child’s role in bullying may serve as either a risk or a protective factor for adult low-grade inflammation, independent of other factors. Inflammation is a physiological response that mediates the effects of both social adversity and dominance on decreases in health.

Added note: I just came across this related article by Raposa et. al. on the developmental pathway from early life stress to inflammation.

Tonics for a long life?

I've recently come across two articles relevant to life extension (work done with mice and worms, to be sure, but a human who reads these papers might well be trying to get their hands on some of the stuff described to give it a try!). Dubai et al. report their work on Klotho, an aging regulator that, when overexpressed, extends lifespan in mice and nematode worms, and, when disrupted, accelerates aging phenotypes. (A lifespan expanding human variant of the KLOTHO gene, KL-VS, is associated with enhanced cognition in heterozygous carriers.) Here is their summary:

Aging is the primary risk factor for cognitive decline, an emerging health threat to aging societies worldwide. Whether anti-aging factors such as klotho can counteract cognitive decline is unknown. We show that a lifespan-extending variant of the human KLOTHO gene, KL-VS, is associated with enhanced cognition in heterozygous carriers. Because this allele increased klotho levels in serum, we analyzed transgenic mice with systemic overexpression of klotho. They performed better than controls in multiple tests of learning and memory. Elevating klotho in mice also enhanced long-term potentiation, a form of synaptic plasticity, and enriched synaptic GluN2B, an N-methyl-D-aspartate receptor (NMDAR) subunit with key functions in learning and memory. Blockade of GluN2B abolished klotho-mediated effects. Surprisingly, klotho effects were evident also in young mice and did not correlate with age in humans, suggesting independence from the aging process. Augmenting klotho or its effects may enhance cognition and counteract cognitive deficits at different life stages.

And, Ye et al. have done a screen, using nematodes, of over 1200 drugs active on human cells, including drugs approved for human use, finding ~60 that increase C. elegans lifespan up to 43%. They mainly act on proteins that function in signaling pathways between cells relevant to oxidative stress resistance - hormone or neurotransmitter receptors, particularly those for adrenaline and noradrenaline, serotonin, dopamine, histamine, and serotonin. This suggests and narrows down a list of drugs that might be tested for life extension in mammals.

One goal of aging research is to find drugs that delay the onset of age-associated disease. Studies in invertebrates, particularly Caenorhabditis elegans, have uncovered numerous genes involved in aging, many conserved in mammals. However, which of these encode proteins suitable for drug targeting is unknown. To investigate this question, we screened a library of compounds with known mammalian pharmacology for compounds that increase C. elegans lifespan. We identified 60 compounds that increase longevity in C. elegans, 33 of which also increased resistance to oxidative stress. Many of these compounds are drugs approved for human use. Enhanced resistance to oxidative stress was associated primarily with compounds that target receptors for biogenic amines, such as dopamine or serotonin. A pharmacological network constructed with these data reveal that lifespan extension and increased stress resistance cluster together in a few pharmacological classes, most involved in intercellular signaling. These studies identify compounds that can now be explored for beneficial effects on aging in mammals, as well as tools that can be used to further investigate the mechanisms underlying aging in C. elegans.

Rapidity of human brain and muscle evolution - the downside of smarts?

Roberts does a summary of fascinating work by Bozak et al. He sets the context: 

Somewhat narcissistically, one of the spectacular changes in phenotype that we tend to be most interested in is the enhancement in our own brain power which has occurred over the 6 million years that separate us from our last shared ancestor with chimpanzees. The chimp genome is famously very similar to our own, but the technological, linguistic, and cultural phenotype is clearly profoundly different. Several studies have asked open-ended questions as to what happens between the genotype and phenotype to make us so different from our cousins, finding differences in levels, splicing, and editing of gene transcripts, for example. Now a paper just published in PLOS Biology by Katarzyna Bozek, Philipp Khaitovich, and colleagues looks at another intermediate phenotype—the metabolome—with some intriguing and unexpected answers...The metabolome is the set of small molecules (metabolites) that are found in a given tissue; by “small” we mean those with a molecular weight of less than 1,500 Daltons, which includes fats, amino acids, sugars, nucleotides, and vitamins (vitamin B12, for example, is near the top end of this range).  

...the metabolomes of human prefrontal cortex (and of combined brain regions) have changed four times as rapidly in the last 6 million years as those of chimps. While gratifying, this largely confirms for metabolites what was already known for transcripts. 

...brain is not the most spectacular outlier here. The real surprise is that the human muscle metabolome has experienced more than eight times as much change as its chimp counterpart. Indeed, metabolomically speaking, human muscle has changed more in the last 6 million years than mouse muscle has since we parted company from mice back in the Early Cretaceous.  

...the authors compared the performance of humans, chimps, and macaques in a strength test that involved pulling a handle to raise a weight. Human strength, as measured by this test, was barely half that of the non-human primates. Amazingly, untrained chimps and macaques raised in captivity easily outperformed university-level basketball players and professional mountain climbers. The authors speculate that the fates of human brain and muscle may be inextricably entwined, and that weak muscle may be the price we pay for the metabolic demands of our amazing cognitive powers.

A Monday musical offering - Poulenc Improvisation No. 7

This is recorded on the Steinway B at my Twin Valley Rd. residence in Middleton, WI.  I used to regularly post my piano work on MindBlog, and will try to return to the habit.

First direct evidence for human sex pheromones.

Here is a clever experiment by Zhou et al., who digitally morph the gender of moving point light displays of walking from male to female while subjects are exposed to two human steroids that they can not discriminate. Here is their summary and abstract:

•Human steroid androstadienone conveys masculinity to straight women and gay men
•Human steroid estratetraenol conveys femininity to straight men
•The effects take place in the absence of awareness
•Human gender perception draws on subconscious chemosensory biological cues

Recent studies have suggested the existence of human sex pheromones, with particular interest in two human steroids: androstadienone (androsta-4,16,-dien-3-one) and estratetraenol (estra-1,3,5(10),16-tetraen-3-ol). The current study takes a critical step to test the qualification of the two steroids as sex pheromones by examining whether they communicate gender information in a sex-specific manner. By using dynamic point-light displays that portray the gaits of walkers whose gender is digitally morphed from male to female, we show that smelling androstadienone systematically biases heterosexual females, but not males, toward perceiving the walkers as more masculine. By contrast, smelling estratetraenol systematically biases heterosexual males, but not females, toward perceiving the walkers as more feminine. Homosexual males exhibit a response pattern akin to that of heterosexual females, whereas bisexual or homosexual females fall in between heterosexual males and females. These effects are obtained despite that the olfactory stimuli are not explicitly discriminable. The results provide the first direct evidence that the two human steroids communicate opposite gender information that is differentially effective to the two sex groups based on their sexual orientation. Moreover, they demonstrate that human visual gender perception draws on subconscious chemosensory biological cues, an effect that has been hitherto unsuspected.

Social attention and our ventromedial prefrontal cortex.

Ralph Adolphs points to an interesting article by Wolf et al. showing that bilateral ventromedial prefrontal cortex damage impairs visual attention to the eye regions of faces, particularly for fearful faces. From Adolphs summary:

Failing to look at the eyes. Shown in each image are the regions of a face at which different groups of subjects look, as measured using eye-tracking. The hottest colours (red regions) denote those regions of the face where people look the most. Whereas this corresponds to the eye region of the face in healthy controls (far left), it is abnormal in certain clinical populations, including individuals with lesions of the vmPFC (top right) or amygdala (bottom right) and individuals with autism spectrum disorder (bottom centre) Top row: from Wolf et al. 2014. Bottom row: data from Michael Spezio, Daniel Kennedy, Ralph Adolphs. All images represent spatially smoothed data averaged across multiple fixations, multiple stimuli and multiple subjects within the indicated group.

Blue Mind - looking at water improves your health and calm

I just spend three days this past weekend in a guesthouse cabin in Door County, Wisconsin - three days of seeing mainly gorgeous green forests and the blue expanses of Lake Michigan on both sides of the Door County peninsula. Over those days, just looking at the water, I could feel a calm growing that quieted my normally chattering mind. Now, back in my university office, what do I stumble across but an article (on stress) that mentions this calming effect of water, a review by Michael Gross titled "Chronic stress means we’re always on the hunt", which first notes that one relief described for chronic stress (dubbed "Red Mind") is to give the stress system some real exercise (doing something like sky diving) to put the more mundane stresses of daily life in perspective. But then, in a second portion of his article, he points to work of Wallace J. Nichols and others who use the phrase "Blue mind" to describe the interface between our psychology and natural environment, particularly water, the largest feature of that environment. Gross notes that Nichols has put his ideas

...in a new book, called Blue Mind: How Water Makes You Happier, More Connected, and Better at What You Do, which is due to appear in June. In his book, Nichols discusses a spate of recent psychology papers showing that the proximity of “blue nature” can improve people’s physical and mental health and counterbalance the damaging effects of the chronic stress and the permanent engagement of the red mind. While the opportunity to exercise plays a part, several studies have shown that the positive effect of being near water can be separated from that aspect.

Crowdsourcing our brain’s wiring.

You too can be be a neuroscientist! I have to join in the general chorus of press pointing to the efforts of Sebastian Seung, now moving from MIT to Princeton Univ. Detailed analysis of serial ultra-thin electron microscope sections of brain neurons is extremely laborious - tracing one cells takes about 50 hours. Seung has asked for help from the general public ("citizen neuroscientists") in doing this with neurons in the mouse retina. The data on how bipolar cells connect to amacrine motion detecting cells in the retina has suggested a model for motion detection. This animation of their results is a treat to watch:

The science of inequality.

The May 23 issue of Science Magazine has a large section devoted the origins and analysis of economic inequality. And, the general gist of virtually all the articles is that inequality is here to stay, predicted by social and also simple physical models of exchange. A weekly chaos and complexity discussion group that I attend just this past Tuesday discussed the economic Yard-Sale Model of wealth redistribution, in which power-law-like distributions result even when all individuals are identical and playing by the same rules. In a previous post, I have passed on a simple model illustrated by Clint Sprott, organizer of the seminars.

The monkey business illusion.

Many people have by now viewed the famous "Gorilla Video" made by Daniel Simons over fifteen years ago, in which most viewers asked to count how many times students are passing a basketball to each other completely miss the fact that a gorilla walks through the middle of the scene halfway through the exercise. I'm passing on Simons' update of his original demonstration, which shows further how we see what we want or expect to see. It has been viewed over 4 million times, and gives links to his other work and publications. (The video is public on youtube, but copyrighted, so I hope Mr. Simons doesn't mind this advertisement for his work.)

 

How social equality is represented in the brain.

Interesting work from Aoki, Adolphs, and collaborators:

A distinct aspect of the sense of fairness in humans is that we care not only about equality in material rewards but also about equality in nonmaterial values. One such value is the opportunity to choose freely among many options, often regarded as a fundamental right to economic freedom. In modern developed societies, equal opportunities in work, living, and lifestyle are enforced by antidiscrimination laws. Despite the widespread endorsement of equal opportunity, no studies have explored how people assign value to it. We used functional magnetic resonance imaging to identify the neural substrates for subjective valuation of equality in choice opportunity. Participants performed a two-person choice task in which the number of choices available was varied across trials independently of choice outcomes. By using this procedure, we manipulated the degree of equality in choice opportunity between players and dissociated it from the value of reward outcomes and their equality. We found that activation in the ventromedial prefrontal cortex (vmPFC) tracked the degree to which the number of options between the two players was equal. In contrast, activation in the ventral striatum tracked the number of options available to participants themselves but not the equality between players. Our results demonstrate that the vmPFC, a key brain region previously implicated in the processing of social values, is also involved in valuation of equality in choice opportunity between individuals. These findings may provide valuable insight into the human ability to value equal opportunity, a characteristic long emphasized in politics, economics, and philosophy.

Note: The same issue of Journal of Neuroscience has a related article by Matthew Apps and Ramnani showing that activity in the anterior cingulate gyrus covaries with the net value of rewards that someone else will receive when that person is required to exert effort for the reward.

Brain correlates of expertise in musical improvisation

Pihno et al. show that expertise in musical improvisation is associated with increased connectivity between premotor and prefrontal areas, suggesting that the ability to produce novel output can be automated by training:

Musicians have been used extensively to study neural correlates of long-term practice, but no studies have investigated the specific effects of training musical creativity. Here, we used human functional MRI to measure brain activity during improvisation in a sample of 39 professional pianists with varying backgrounds in classical and jazz piano playing. We found total hours of improvisation experience to be negatively associated with activity in frontoparietal executive cortical areas. In contrast, improvisation training was positively associated with functional connectivity of the bilateral dorsolateral prefrontal cortices, dorsal premotor cortices, and presupplementary areas. The effects were significant when controlling for hours of classical piano practice and age. These results indicate that even neural mechanisms involved in creative behaviors, which require a flexible online generation of novel and meaningful output, can be automated by training. Second, improvisational musical training can influence functional brain properties at a network level. We show that the greater functional connectivity seen in experienced improvisers may reflect a more efficient exchange of information within associative networks of importance for musical creativity.

Brain correlates of "the good life" ??

Lewis et al. offer another example of the class of experiments correlating the volume of a specific brain area with a specific behavior, in this case eudaimonic well-being, which is positively correlated with volume in the right insular cortex. Eudaimonia is fundamentally linked to notions of agency, and recent work has identified insular cortex as a source of agentic control. The insula has also been linked to facilitation of self-awareness, as well as to the regulation of bodily states and modulation of decision making based on interoceptive information about these bodily states.

Whether the behavior causes the larger insular volume or vice versa can’t be determined. These particular experiments did not control for simple subjective (hedonic) well-being, so the observed volume increase in the insula may not be a unique correlate of eudaimonia. Here is their abstract, and the entire text of the article is open source.

Eudaimonic well-being reflects traits concerned with personal growth, self-acceptance, purpose in life and autonomy (among others) and is a substantial predictor of life events, including health. Although interest in the aetiology of eudaimonic well-being has blossomed in recent years, little is known of the underlying neural substrates of this construct. To address this gap in our knowledge, here we examined whether regional gray matter (GM) volume was associated with eudaimonic well-being. Structural magnetic resonance images from 70 young, healthy adults who also completed Ryff’s 42-item measure of the six core facets of eudaimonia, were analysed with voxel-based morphometry techniques. We found that eudaimonic well-being was positively associated with right insular cortex GM volume. This association was also reflected in three of the sub-scales of eudaimonia: personal growth, positive relations and purpose in life. Positive relations also showed a significant association with left insula volume. No other significant associations were observed, although personal growth was marginally associated with left insula, and purpose in life exhibited a marginally significant negative association with middle temporal gyrus GM volume. These findings are the first to our knowledge linking eudaimonic well-being with regional brain structure.

Stress can protect from Alzheimer's disease

Yanker and his collaborators have found that levels of a neuro-protective protein called REST (repressor element 1-silencing transcription factor) are increased in the brain by any form of cellular stress (oxidative, immune, etc.) It acts by repressing genes involved in cell death and Alzheimer's dementia. REST levels in prefrontal cortical neurons are positively correlated with a measure of global cognition, and also separate measures of episodic, semantic and working memory. Measurements of autopsied brains of elderly people who have died of Alzheimer's are three times lower than in the brains of people the same age without dementia. Here is their abstract:

Human neurons are functional over an entire lifetime, yet the mechanisms that preserve function and protect against neurodegeneration during ageing are unknown. Here we show that induction of the repressor element 1-silencing transcription factor (REST; also known as neuron-restrictive silencer factor, NRSF) is a universal feature of normal ageing in human cortical and hippocampal neurons. REST is lost, however, in mild cognitive impairment and Alzheimer’s disease. Chromatin immunoprecipitation with deep sequencing and expression analysis show that REST represses genes that promote cell death and Alzheimer’s disease pathology, and induces the expression of stress response genes. Moreover, REST potently protects neurons from oxidative stress and amyloid β-protein toxicity, and conditional deletion of REST in the mouse brain leads to age-related neurodegeneration. A functional orthologue of REST, Caenorhabditis elegans SPR-4, also protects against oxidative stress and amyloid β-protein toxicity. During normal ageing, REST is induced in part by cell non-autonomous Wnt signalling. However, in Alzheimer’s disease, frontotemporal dementia and dementia with Lewy bodies, REST is lost from the nucleus and appears in autophagosomes together with pathological misfolded proteins. Finally, REST levels during ageing are closely correlated with cognitive preservation and longevity. Thus, the activation state of REST may distinguish neuroprotection from neurodegeneration in the ageing brain.

Fear detection depends on phase of our heartbeats.

Here's a fascinating piece of work:

Cognitions and emotions can be influenced by bodily physiology. Here, we investigated whether the processing of brief fear stimuli is selectively gated by their timing in relation to individual heartbeats. Emotional and neutral faces were presented to human volunteers at cardiac systole, when ejection of blood from the heart causes arterial baroreceptors to signal centrally the strength and timing of each heartbeat, and at diastole, the period between heartbeats when baroreceptors are quiescent. Participants performed behavioral and neuroimaging tasks to determine whether these interoceptive signals influence the detection of emotional stimuli at the threshold of conscious awareness and alter judgments of emotionality of fearful and neutral faces. Our results show that fearful faces were detected more easily and were rated as more intense at systole than at diastole. Correspondingly, amygdala responses were greater to fearful faces presented at systole relative to diastole. These novel findings highlight a major channel by which short-term interoceptive fluctuations enhance perceptual and evaluative processes specifically related to the processing of fear and threat and counter the view that baroreceptor afferent signaling is always inhibitory to sensory perception.

Correlation between prosocial behavior and computer game playing

Here's what seems to me a a slightly counter-intuitive result. Numerous studies have a noted a correlation between playing violent computer games and less prosocial behavior, and studies of games involving cooperation correlate with more prosocial behaviors. Most of these studies have observed behaviors immediately after palying the games. Mengel takes a more neutral approach and simply asks whether there is a correlation between average daily time spent playing any sort of computer game and prosocial behavior assayed with the Prisoner's dilemma game over 10 different periods, with participating students also reporting on their daily computer use. They find the average cooperation rate is positively correlated with the self-reported amount of time participants spend playing computer games. None of the other computer time use variables (including time spent on social media, browsing internet, working etc.) are significantly related to cooperation rates.  (So...either cooperative students are more likely to spend a lot of time on computer games, or computer games enhance cooperative behavior... or... neither of the above.)

What drives collective versus individualistic behaviors?

Talheim et al. offer a strikingly simple explanation for why collective versus individualistic behaviors may arise in a given cultural group. Rather than the usual comparison of Western and Asian cultures as a whole, they look at large-scale psychological differences with China, and find that they correlate with the different behavioral requirements of rice versus wheat agriculture:

Cross-cultural psychologists have mostly contrasted East Asia with the West. However, this study shows that there are major psychological differences within China. We propose that a history of farming rice makes cultures more interdependent, whereas farming wheat makes cultures more independent, and these agricultural legacies continue to affect people in the modern world. We tested 1162 Han Chinese participants in six sites and found that rice-growing southern China is more interdependent and holistic-thinking than the wheat-growing north. To control for confounds like climate, we tested people from neighboring counties along the rice-wheat border and found differences that were just as large. We also find that modernization and pathogen prevalence theories do not fit the data.

From Henrich's description of their methods:

To investigate the individualism and analytical thinking in participants from different agricultural regions in China, Talhelm et al. used three tests. They measured analytical thinking with a series of triads. Participants were given a target object, such as a rabbit, and asked which of two other objects it goes with. Analytic thinkers tend to match on categories, so rabbits and dogs go together. Holistic thinkers tend to match on relationships, so rabbits eat carrots. The authors also measured individualism in two ways. First, they asked participants to draw a sociogram, with labeled circles representing themselves and their friends. In this test, individualism is measured implicitly by how much bigger the “self” circle is relative to the average “friends” circle. Second, they assessed the nepotism (in-group loyalty) of participants by asking them about hypothetical scenarios in which they could reward or punish friends and strangers for helpful or harmful action.

Morality and perception speed

Here is an interesting nugget... We are more likely to see a word flashed for a very brief interval if it has moral valence. Words related to morality can be identified after a 40-millisecond peek, but nonmoral words needed an extra 10 ms of exposure. From Gantman and Bavel:

Highlights

• We examined whether moral concerns shape awareness of ambiguous stimuli.
• Participants saw moral and non-moral words in a lexical decision task.
• Moral and non-moral words were matched on length, and frequency in lexicon.
• Participants correctly identified moral words more frequently than non-moral words.
• This experiments suggest that moral values may shape perceptual awareness.

Abstract

People perceive religious and moral iconography in ambiguous objects, ranging from grilled cheese to bird feces. In the current research, we examined whether moral concerns can shape awareness of perceptually ambiguous stimuli. In three experiments, we presented masked moral and non-moral words around the threshold for conscious awareness as part of a lexical decision task. Participants correctly identified moral words more frequently than non-moral words—a phenomenon we term the moral pop-out effect. The moral pop-out effect was only evident when stimuli were presented at durations that made them perceptually ambiguous, but not when the stimuli were presented too quickly to perceive or slowly enough to easily perceive. The moral pop-out effect was not moderated by exposure to harm and cannot be explained by differences in arousal, valence, or extremity. Although most models of moral psychology assume the initial perception of moral stimuli, our research suggests that moral beliefs and values may shape perceptual awareness.

Sluggish cognitive tempo, a new diagnosis du jour?

The drug companies may be finding a new profit center, having maxed out their ability to push pills on the more than 6 million American children who have received a diagnosis of A.D.H.D. (attention deficit hyperactivity disorder, which in my son’s case was evaluated by a sane pediatric psychiatrist who wisely said “Chill, he’s just acting like a kid.”) The new syndrome, summarized by Schwartz, is called sluggish cognitive tempo and said to be characterized by lethargy, daydreaming and slow mental processing. It is the subject of the entire January issue of The Journal of Abnormal Child Psychology.

Papers have proposed that a recognition of sluggish cognitive tempo could help resolve some longstanding confusion about A.D.H.D., which despite having hyperactivity in its name includes about two million children who are not hyperactive, merely inattentive. Some researchers propose that about half of those children would be better classified as having sluggish cognitive tempo, with perhaps one million additional children, who do not meet A.D.H.D.’s criteria now, having the new disorder, too.

The syndrome is not well defined, and many researchers refuse to discuss it, or their financial interests in the condition’s acceptance.

The description I find most intriguing and plausible is of a syndrome that involves extreme mind wandering, perhaps of a brain that is chronically in the “default” mode (described in a number of MindBlog posts) and unable to (or unwilling or too lazy to) activate the “attentional” or goal oriented, direct experiential focus, task positive network appropriately.  (Think about the teenagers behind fast-food counters completely unable to do simple addition and subtraction!). The best therapy for this syndrome would seem to be cognitive or behavioral (i.e. "SHAPE UP!"), rather than another pill to pop.

Drug treatments of this or other behavioral syndromes such as depression have the risk of diminishing personal agency and responsibility, as Iarovici notes:

We walk a thinning line between diagnosing illness and teaching our youth to view any emotional upset as pathological. We need a greater focus on building resilience in emerging adults. We need more scientific studies — spanning years, not months — on the risks and benefits of maintenance treatment in emerging adults.

Formation of new brain cells can erase old memories

Over the past ten years it has been established that generation of new nerve cells in the dentate gyrus portion of our brains' hippocampus is required for hippocampus dependent learning and memory recall. Akers et al. now show that this neurogenesis may also promote forgetting. So, it would appear that while not enough neurogenesis inhibits learning and enhanced neurogenesis enhances it, the ongoing circuit remodeling caused by higher neurogenesis can also make the memories more laible. Thus, there may be a compromise “trade-off” level of neurogenesis that allows good performance for both memory acquisition and retention. The abstract:

Throughout life, new neurons are continuously added to the dentate gyrus. As this continuous addition remodels hippocampal circuits, computational models predict that neurogenesis leads to degradation or forgetting of established memories. Consistent with this, increasing neurogenesis after the formation of a memory was sufficient to induce forgetting in adult mice. By contrast, during infancy, when hippocampal neurogenesis levels are high and freshly generated memories tend to be rapidly forgotten (infantile amnesia), decreasing neurogenesis after memory formation mitigated forgetting. In precocial species, including guinea pigs and degus, most granule cells are generated prenatally. Consistent with reduced levels of postnatal hippocampal neurogenesis, infant guinea pigs and degus did not exhibit forgetting. However, increasing neurogenesis after memory formation induced infantile amnesia in these species.

Nonconscious emotions and first impressions - role for conscious awareness

I just came across this interesting article from Davidson and collaborators at Wisconsin:

Emotions can color people’s attitudes toward unrelated objects in the environment. Existing evidence suggests that such emotional coloring is particularly strong when emotion-triggering information escapes conscious awareness. But is emotional reactivity stronger after nonconscious emotional provocation than after conscious emotional provocation, or does conscious processing specifically change the association between emotional reactivity and evaluations of unrelated objects? In this study, we independently indexed emotional reactivity and coloring as a function of emotional-stimulus awareness to disentangle these accounts. Specifically, we recorded skin-conductance responses to spiders and fearful faces, along with subsequent preferences for novel neutral faces during visually aware and unaware states. Fearful faces increased skin-conductance responses comparably in both stimulus-aware and stimulus-unaware conditions. Yet only when visual awareness was precluded did skin-conductance responses to fearful faces predict decreased likability of neutral faces. These findings suggest a regulatory role for conscious awareness in breaking otherwise automatic associations between physiological reactivity and evaluative emotional responses.

Language universals at birth.

Fascinating observations from Gómez et al. showing that human babies are born with linguistic biases concerning syllable structure:

The evolution of human languages is driven both by primitive biases present in the human sensorimotor systems and by cultural transmission among speakers. However, whether the design of the language faculty is further shaped by linguistic biological biases remains controversial. To address this question, we used near-infrared spectroscopy to examine whether the brain activity of neonates is sensitive to a putatively universal phonological constraint. Across languages, syllables like blif are preferred to both lbif and bdif. Newborn infants (2–5 d old) listening to these three types of syllables displayed distinct hemodynamic responses in temporal-perisylvian areas of their left hemisphere. Moreover, the oxyhemoglobin concentration changes elicited by a syllable type mirrored both the degree of its preference across languages and behavioral linguistic preferences documented experimentally in adulthood. These findings suggest that humans possess early, experience-independent, linguistic biases concerning syllable structure that shape language perception and acquisition.

GABA predicts time perception.

Individuals can vary widely in their ability to detect sub-second visual stimuli, and most cognitive training and exercise regimes have exercises designed to enhance detection of shorter (50-200 millisecond) intervals. Terhune et al. make the interesting observation that this variability correlates with the resting state levels of the inhibitory transmitter GABA (gamma-amino butyric acid)in our visual cortex, such that elevated GABA is associated with underestimating the duration of subsecond visual intervals:

Our perception of time constrains our experience of the world and exerts a pivotal influence over a myriad array of cognitive and motor functions. There is emerging evidence that the perceived duration of subsecond intervals is driven by sensory-specific neural activity in human and nonhuman animals, but the mechanisms underlying individual differences in time perception remain elusive. We tested the hypothesis that elevated visual cortex GABA impairs the coding of particular visual stimuli, resulting in a dampening of visual processing and concomitant positive time-order error (relative underestimation) in the perceived duration of subsecond visual intervals. Participants completed psychophysical tasks measuring visual interval discrimination and temporal reproduction and we measured in vivo resting state GABA in visual cortex using magnetic resonance spectroscopy. Time-order error selectively correlated with GABA concentrations in visual cortex, with elevated GABA associated with a rightward horizontal shift in psychometric functions, reflecting a positive time-order error (relative underestimation). These results demonstrate anatomical, neurochemical, and task specificity and suggest that visual cortex GABA contributes to individual differences in time perception.

More on the rejuvenating power of young blood...

Since my "fountain of youth" post in 2011 there has been a burst of research showing that factors in the blood of younger animals can actually reverse the aging process in older ones. Carl Zimmer points to several of the studies. Wagers and collaborators find that restoring levels of a circulating protein growth differentiation factor 11 (GDF11), a skeletal muscle rejuvenating factor whose levels normally decline with age, reverses muscle dysfunction by increased stength and endurance exercise capacity. Further, GDF11 alone can improve the cerebral vasculature and enhance neurogenesis. Villeda et al find that structural and cognitive enhancements elicited by exposure to young blood are mediated, in part, by activation of the cyclic AMP response element binding protein (Creb) in the aged hippocampus.

So, should we all be rushing out to shoot ourselves up with injections of GDF!!? Maybe not... waking up too many stem cells to start multiplying might increase the incidence of cancer.

Brain activity display in the spirit of P.T. Barnum

Carl Zimmer points to some amazing brain graphics, notably one from Gazzaley's lab. You should use the gear symbol to slow down the graphic, and set the resolution to high definition if your computer supports it. Setting the screen to full display and frequently pausing the play through lets you see all sorts of moving flashing lights going to and from familiar brain areas, but what's the behavioral or subjective correlate??


 This is great show-biz, but I wish Zimmer's statement that "the volunteer was simply asked to open and shut her eyes and open and close her hand." appeared here and that the moving graphics were labelled "eye shutting" "eye opening" "hand opening" "hand closing," and could they maybe tell us which colors refer to which frequency bands? Very frustrating. Maybe if I dug a bit more diligently on their websites I could find the information, but at this point I'm not willing to spend more time on it. Here is the description provided:

This is an anatomically-realistic 3D brain visualization depicting real-time source-localized activity (power and "effective" connectivity) from EEG (electroencephalographic) signals. Each color represents source power and connectivity in a different frequency band (theta, alpha, beta, gamma) and the golden lines are white matter anatomical fiber tracts. Estimated information transfer between brain regions is visualized as pulses of light flowing along the fiber tracts connecting the regions.

The modeling pipeline includes MRI (Magnetic Resonance Imaging) brain scanning to generate a high-resolution 3D model of an individual's brain, skull, and scalp tissue, DTI (Diffusion Tensor Imaging) for reconstructing white matter tracts, and BCILAB (http://sccn.ucsd.edu/wiki/BCILAB) / SIFT (http://sccn.ucsd.edu/wiki/SIFT) to remove artifacts and statistically reconstruct the locations and dynamics (amplitude and multivariate Granger-causal (http://www.scholarpedia.org/article/G...) interactions) of multiple sources of activity inside the brain from signals measured at electrodes on the scalp (in this demo, a 64-channel "wet" mobile system by Cognionics/BrainVision (http://www.cognionics.com)).

The final visualization is done in Unity and allows the user to fly around and through the brain with a gamepad while seeing real-time live brain activity from someone wearing an EEG cap.

We transfer reward in a bottom-up search task to a top-down search task.

Lee and Shomstein make the interesting observation that a reward-based contingency learned in a bottom-up search task can be transferred to a subsequent top-down search task. They define the two kinds of search task in their introduction:

Research has demonstrated that the allocation of attention is controlled by two partially segregated networks of brain areas. The top-down attention system, which recruits parts of the intraparietal and superior frontal cortices, is specialized for selecting stimuli on the basis of cognitive factors, such as current goals and expectations. The bottom-up attention system, by contrast, recruits the temporoparietal and inferior frontal cortices, and is involved in processing stimuli on the basis of stimulus-driven factors, such as physical salience and novelty.

Here is their abstract:

Recent evidence has suggested that reward modulates bottom-up and top-down attentional selection and that this effect persists within the same task even when reward is no longer offered. It remains unclear whether reward effects transfer across tasks, especially those engaging different modes of attention. We directly investigated whether reward-based contingency learned in a bottom-up search task was transferred to a subsequent top-down search task, and probed the nature of the transfer mechanism. Results showed that a reward-related benefit established in a pop-out-search task was transferred to a conjunction-search task, increasing participants’ efficiency at searching for targets previously associated with a higher level of reward. Reward history influenced search efficiency by enhancing both target salience and distractor filtering, depending on whether the target and distractors shared a critical feature. These results provide evidence for reward-based transfer between different modes of attention and strongly suggest that an integrated priority map based on reward information guides both top-down and bottom-up attention.

Gene expression changes in expert meditators?

Interesting data from an international collaboration. (Although, it seems the more useful design would have been to do a double blind experiment in which half of a group of experienced meditators performed the intensive practice while the other half, in a similar environment, did not.)

 Background

A growing body of research shows that mindfulness meditation can alter neural, behavioral and biochemical processes. However, the mechanisms responsible for such clinically relevant effects remain elusive.

Methods

Here we explored the impact of a day of intensive practice of mindfulness meditation in experienced subjects (n = 19) on the expression of circadian, chromatin modulatory and inflammatory genes in peripheral blood mononuclear cells (PBMC). In parallel, we analyzed a control group of subjects with no meditation experience who engaged in leisure activities in the same environment (n = 21). PBMC from all participants were obtained before (t1) and after (t2) the intervention (t2 − t1 = 8 h) and gene expression was analyzed using custom pathway focused quantitative-real time PCR assays. Both groups were also presented with the Trier Social Stress Test (TSST).

Results

Core clock gene expression at baseline (t1) was similar between groups and their rhythmicity was not influenced in meditators by the intensive day of practice. Similarly, we found that all the epigenetic regulatory enzymes and inflammatory genes analyzed exhibited similar basal expression levels in the two groups. In contrast, after the brief intervention we detected reduced expression of histone deacetylase genes (HDAC 2, 3 and 9), alterations in global modification of histones (H4ac; H3K4me3) and decreased expression of pro-inflammatory genes (RIPK2 and COX2) in meditators compared with controls. We found that the expression of RIPK2 and HDAC2 genes was associated with a faster cortisol recovery to the TSST in both groups.

Conclusions

The regulation of HDACs and inflammatory pathways may represent some of the mechanisms underlying the therapeutic potential of mindfulness-based interventions. Our findings set the foundation for future studies to further assess meditation strategies for the treatment of chronic inflammatory conditions.

The smell of sickness.

Olsson et al. demonstrate the existence of a olfactory signal of illness, a aversive body odor that can signal other humans to keep their distance from a diseased person, but they do not identify the volatile chemicals that must be involved.:

Observational studies have suggested that with time, some diseases result in a characteristic odor emanating from different sources on the body of a sick individual. Evolutionarily, however, it would be more advantageous if the innate immune response were detectable by healthy individuals as a first line of defense against infection by various pathogens, to optimize avoidance of contagion. We activated the innate immune system in healthy individuals by injecting them with endotoxin (lipopolysaccharide). Within just a few hours, endotoxin-exposed individuals had a more aversive body odor relative to when they were exposed to a placebo. Moreover, this effect was statistically mediated by the individuals’ level of immune activation. This chemosensory detection of the early innate immune response in humans represents the first experimental evidence that disease smells and supports the notion of a “behavioral immune response” that protects healthy individuals from sick ones by altering patterns of interpersonal contact.

Out of body, out of mind.

Bergouignan et al. do a neat experiment in which they test how well study participants remember a presentation when they experience being in their own bodies versus out of their bodies looking at the presentation from another perspective. They find that if an event is experienced from an 'out-of-body' perspective, it is remembered less well and its recall does not induce the usual pattern of hippocampal activation. This means that hippocampus-based episodic memory depends on the perception of the world from within our own bodies, and that a dissociative experience during encoding blocks the memory-forming mechanism. Here is their abstract, followed by a description of how they set up out of body experience.

Theoretical models have suggested an association between the ongoing experience of the world from the perspective of one’s own body and hippocampus-based episodic memory. This link has been supported by clinical reports of long-term episodic memory impairments in psychiatric conditions with dissociative symptoms, in which individuals feel detached from themselves as if having an out-of-body experience. Here, we introduce an experimental approach to examine the necessary role of perceiving the world from the perspective of one’s own body for the successful episodic encoding of real-life events. While participants were involved in a social interaction, an out-of-body illusion was elicited, in which the sense of bodily self was displaced from the real body to the other end of the testing room. This condition was compared with a well-matched in-body illusion condition, in which the sense of bodily self was colocalized with the real body. In separate recall sessions, performed ∼1 wk later, we assessed the participants’ episodic memory of these events. The results revealed an episodic recollection deficit for events encoded out-of-body compared with in-body. Functional magnetic resonance imaging indicated that this impairment was specifically associated with activity changes in the posterior hippocampus. Collectively, these findings show that efficient hippocampus-based episodic-memory encoding requires a first-person perspective of the natural spatial relationship between the body and the world. Our observations have important implications for theoretical models of episodic memory, neurocognitive models of self, embodied cognition, and clinical research into memory deficits in psychiatric disorders.

The setup:

During the life events to be remembered (“encoding sessions”), the participants sat in a chair and wore a set of head-mounted displays (HMDs) and earphones, which were connected to two closed-circuit television (CCTV) cameras and to an advanced “dummy-head microphone,” respectively. This technology enabled the participants to see and hear the testing room in three dimensions from the perspective of the cameras mounted with the dummy head microphones. The cameras were either placed immediately above and behind the actual head of the participant, creating an experience of the room from the perspective of the real body (in-body condition), or the cameras were placed 2 m in front or to the side of the participant, thus making the participants experience the room and the individuals in it as an observer outside of their real body (out-of-body condition). To induce the strong illusion of being fully located in one of these two locations and sensing an illusory body in this place, we repetitively moved a rod toward a location below the cameras and synchronously touched the participant’s chest for a period of 70 s, which provided congruent multisensory stimulation to elicit illusory perceptions. The illusion was maintained for 5 min, during which the ecologically valid life events took place (see next section); throughout this period, the participant received spatially congruent visual and auditory information via the synchronized HMDs and dummy head microphones, which further facilitated the maintenance of the illusion.

Oxytocin promotes group-serving dishonesty

Like Lewis Carroll's Wonderland, the oxytocin story gets curiouser and curiouser.... this from Shalvi and De Dreu:

To protect and promote the well-being of others, humans may bend the truth and behave unethically. Here we link such tendencies to oxytocin, a neuropeptide known to promote affiliation and cooperation with others. Using a simple coin-toss prediction task in which participants could dishonestly report their performance levels to benefit their group’s outcome, we tested the prediction that oxytocin increases group-serving dishonesty. A double-blind, placebo-controlled experiment allowing individuals to lie privately and anonymously to benefit themselves and fellow group members showed that healthy males (n = 60) receiving intranasal oxytocin, rather than placebo, lied more to benefit their group, and did so faster, yet did not necessarily do so because they expected reciprocal dishonesty from fellow group members. Treatment effects emerged when lying had financial consequences and money could be gained; when losses were at stake, individuals in placebo and oxytocin conditions lied to similar degrees. In a control condition (n = 60) in which dishonesty only benefited participants themselves, but not fellow group members, oxytocin did not influence lying. Together, these findings fit a functional perspective on morality revealing dishonesty to be plastic and rooted in evolved neurobiological circuitries, and align with work showing that oxytocin shifts the decision-maker’s focus from self to group interests. These findings highlight the role of bonding and cooperation in shaping dishonesty, providing insight into when and why collaboration turns into corruption.

Aesop's crow - evidence of causal understanding

Jelbert et al. show even further smarts in the New Caledonian Crow I've mentioned in several previous posts.

Understanding causal regularities in the world is a key feature of human cognition. However, the extent to which non-human animals are capable of causal understanding is not well understood. Here, we used the Aesop's fable paradigm – in which subjects drop stones into water to raise the water level and obtain an out of reach reward – to assess New Caledonian crows' causal understanding of water displacement. We found that crows preferentially dropped stones into a water-filled tube instead of a sand-filled tube; they dropped sinking objects rather than floating objects; solid objects rather than hollow objects, and they dropped objects into a tube with a high water level rather than a low one. However, they failed two more challenging tasks which required them to attend to the width of the tube, and to counter-intuitive causal cues in a U-shaped apparatus. Our results indicate that New Caledonian crows possess a sophisticated, but incomplete, understanding of the causal properties of displacement, rivaling that of 5–7 year old children.

A blood test for Alzheimers disease?

Mapstone et al. have identified a set of 10 lipids whose levels predict, with an accuracy of over 90%, whether or not an older individual will develop mild cognitive impairment or Alzheimer's disease within 2–3 years. If this work is confirmed by other independent and more extensive studies, we may be seeing a clinical test within a few years. Would this 72 year old take such a test? Probably so, because avoiding the possible bad news would mean I might be less likely to get financial, legal, personal stuff in order (things like planing for care and informing family.)

Alzheimer's disease causes a progressive dementia that currently affects over 35 million individuals worldwide and is expected to affect 115 million by 2050. There are no cures or disease-modifying therapies, and this may be due to our inability to detect the disease before it has progressed to produce evident memory loss and functional decline. Biomarkers of preclinical disease will be critical to the development of disease-modifying or even preventative therapies. Unfortunately, current biomarkers for early disease, including cerebrospinal fluid tau and amyloid-β levels, structural and functional magnetic resonance imaging and the recent use of brain amyloid imaging or inflammaging, are limited because they are either invasive, time-consuming or expensive. Blood-based biomarkers may be a more attractive option, but none can currently detect preclinical Alzheimer's disease with the required sensitivity and specificity. Herein, we describe our lipidomic approach to detecting preclinical Alzheimer's disease in a group of cognitively normal older adults. We discovered and validated a set of ten lipids from peripheral blood that predicted phenoconversion to either amnestic mild cognitive impairment or Alzheimer's disease within a 2–3 year timeframe with over 90% accuracy. This biomarker panel, reflecting cell membrane integrity, may be sensitive to early neurodegeneration of preclinical Alzheimer's disease.

Wave of the future - trusting machines that talk to us.

We're reading that in 10 years we might be able to buy autonomous cars that do the driving for us. Waytz et al. do an interesting study of the psychological consequence of endowing such vehicles with a voice. They monitor self report of emotions and fluctuations in heart rate while subjects either operate a driving simulator themselves, or become the passenger driven by an autonomous that does or doesn't speak to them. Not surprisingly, audio communication increases the sense of liking and trust. Also in the aftermath of a simulated collision programmed so as to be unavoidable, the vocal vehicle is more likely to be absolved of blame. The subjects have attributed human agency to a machine, which I was just doing while driving back to Madison WI from my winter nest in Fort Lauderdale, and found myself cursing the teutonic female voice of my GPS navigator. Here are their highlights and abstract:

Highlights
-Anthropomorphism of a car predicts trust in that car.
-Trust is reflected in behavioral, physiological, and self-report measures.
-Anthropomorphism also affects attributions of responsibility/punishment.  

Abstract 

Sophisticated technology is increasingly replacing human minds to perform complicated tasks in domains ranging from medicine to education to transportation. We investigated an important theoretical determinant of people's willingness to trust such technology to perform competently—the extent to which a nonhuman agent is anthropomorphized with a humanlike mind—in a domain of practical importance, autonomous driving. Participants using a driving simulator drove either a normal car, an autonomous vehicle able to control steering and speed, or a comparable autonomous vehicle augmented with additional anthropomorphic features—name, gender, and voice. Behavioral, physiological, and self-report measures revealed that participants trusted that the vehicle would perform more competently as it acquired more anthropomorphic features. Technology appears better able to perform its intended design when it seems to have a humanlike mind. These results suggest meaningful consequences of humanizing technology, and also offer insights into the inverse process of objectifying humans.

Brain abnormalities caused by marijuana use.

Numerous studies have shown that cannabis use is associated with impairments of cognitive functions, including learning and memory, attention, and decision-making. Animal studies show structural changes in brain regions underlying these functions after exposure to Δ9-tetrahydrocannabinol (THC). Now, a sobering bit of information on structural changes in human brains from Gilman et al.:

Marijuana is the most commonly used illicit drug in the United States, but little is known about its effects on the human brain, particularly on reward/aversion regions implicated in addiction, such as the nucleus accumbens and amygdala. Animal studies show structural changes in brain regions such as the nucleus accumbens after exposure to Δ9-tetrahydrocannabinol, but less is known about cannabis use and brain morphometry in these regions in humans. We collected high-resolution MRI scans on young adult recreational marijuana users and nonusing controls and conducted three independent analyses of morphometry in these structures: (1) gray matter density using voxel-based morphometry, (2) volume (total brain and regional volumes), and (3) shape (surface morphometry). Gray matter density analyses revealed greater gray matter density in marijuana users than in control participants in the left nucleus accumbens extending to subcallosal cortex, hypothalamus, sublenticular extended amygdala, and left amygdala, even after controlling for age, sex, alcohol use, and cigarette smoking. Trend-level effects were observed for a volume increase in the left nucleus accumbens only. Significant shape differences were detected in the left nucleus accumbens and right amygdala. The left nucleus accumbens showed salient exposure-dependent alterations across all three measures and an altered multimodal relationship across measures in the marijuana group. These data suggest that marijuana exposure, even in young recreational users, is associated with exposure-dependent alterations of the neural matrix of core reward structures and is consistent with animal studies of changes in dendritic arborization.

Brain activity underlying subjective awareness

Hill and He devise and interesting paradigm to distinguish brain activities directly contributing to conscious perception from brain activities that precede or follow it. They do this by examining trial by trial objective performance, subjective awareness, and the confidence level of subjective awareness. They find that widely distributed slow cortical potentials in the < 4 Hz (delta) range - i.e. brain activity waves taking longer than a quarter of a second - correlate with subjective awareness, even after the effects of objective performance and confidence (contributed by more transient brain activity) were both removed. Here is their abstract:

Despite intense recent research, the neural correlates of conscious visual perception remain elusive. The most established paradigm for studying brain mechanisms underlying conscious perception is to keep the physical sensory inputs constant and identify brain activities that correlate with the changing content of conscious awareness. However, such a contrast based on conscious content alone would not only reveal brain activities directly contributing to conscious perception, but also include brain activities that precede or follow it. To address this issue, we devised a paradigm whereby we collected, trial-by-trial, measures of objective performance, subjective awareness, and the confidence level of subjective awareness. Using magnetoencephalography recordings in healthy human volunteers, we dissociated brain activities underlying these different cognitive phenomena. Our results provide strong evidence that widely distributed slow cortical potentials (SCPs) correlate with subjective awareness, even after the effects of objective performance and confidence were both removed. The SCP correlate of conscious perception manifests strongly in its waveform, phase, and power. In contrast, objective performance and confidence were both contributed by relatively transient brain activity. These results shed new light on the brain mechanisms of conscious, unconscious, and metacognitive processing.

Blocking facial muscle movement compromizes detecting and having emotions

Rychlowska et al. show that blocking facial mimicry makes true and false smiles look the same:

Recent research suggests that facial mimicry underlies accurate interpretation of subtle facial expressions. In three experiments, we manipulated mimicry and tested its role in judgments of the genuineness of true and false smiles. A first experiment used facial EMG to show that a new mouthguard technique for blocking mimicry modifies both the amount and the time course of facial reactions. In two further experiments, participants rated true and false smiles either while wearing mouthguards or when allowed to freely mimic the smiles with or without additional distraction, namely holding a squeeze ball or wearing a finger-cuff heart rate monitor. Results showed that blocking mimicry compromised the decoding of true and false smiles such that they were judged as equally genuine. Together the experiments highlight the role of facial mimicry in judging subtle meanings of facial expressions.

And, Richard Friedman points to work showing that paralyzing the facial muscles central to frowning with Botox provides relief from depression. Information between brain and muscle clearly flows both ways.

In a study forthcoming in the Journal of Psychiatric Research, Eric Finzi, a cosmetic dermatologist, and Norman Rosenthal, a professor of psychiatry at Georgetown Medical School, randomly assigned a group of 74 patients with major depression to receive either Botox or saline injections in the forehead muscles whose contraction makes it possible to frown. Six weeks after the injection, 52 percent of the subjects who got Botox showed relief from depression, compared with only 15 percent of those who received the saline placebo.

Is it a Stradivarius?

I've published several posts on studies showing that panels of expert wine tasters can not distinguish cheap from expensive wines if their labels are covered, and note preference for the expensive wines only if they know the prices. Now several studies from the world of music make an equivalent finding with respect to the quality of new versus old violins. From Fritz et al.:

Many researchers have sought explanations for the purported tonal superiority of Old Italian violins by investigating varnish and wood properties, plate tuning systems, and the spectral balance of the radiated sound. Nevertheless, the fundamental premise of tonal superiority has been investigated scientifically only once very recently, and results showed a general preference for new violins and that players were unable to reliably distinguish new violins from old. The study was, however, relatively small in terms of the number of violins tested (six), the time allotted to each player (an hour), and the size of the test space (a hotel room). In this study, 10 renowned soloists each blind-tested six Old Italian violins (including five by Stradivari) and six new during two 75-min sessions—the first in a rehearsal room, the second in a 300-seat concert hall. When asked to choose a violin to replace their own for a hypothetical concert tour, 6 of the 10 soloists chose a new instrument. A single new violin was easily the most-preferred of the 12. On average, soloists rated their favorite new violins more highly than their favorite old for playability, articulation, and projection, and at least equal to old in terms of timbre. Soloists failed to distinguish new from old at better than chance levels. These results confirm and extend those of the earlier study and present a striking challenge to near-canonical beliefs about Old Italian violins.

Top Brain, Bottom Brain - a user's manual from Kosslyn and Miller

I thought I would point to a recent book authored by Kosslyn and Miller:  “Top Brain - Bottom Brain: Surprising Insights into How You Think.” They make a good effort to communicate (co-author Miller is a professional journalist/author), yet it is a tough slog at points.

Their basic simplification is to describe the top and the bottom parts of the brain as performing different sorts of tasks. The bottom-brain system classifies and interprets sensory information from the world, and the top-brain system formulates and executes plans. Here is the standard brain graphic from their introduction:

You can have four separate ways of arranging a set of opposites like top and bottom, and they make these into four personality types distinguished by different relative activities of the two.:

To do a disservice to their more balanced and extended presentation, I cut to the chase with an irreverent condensation:

The movers appear to be your winners, top brain action people who actually also use the bottom half to pay attention to the consequences of their actions and use the feedback.

The stimulator is more the ‘damn the cannons, full speed ahead’ kind of person, less inclined to attend to the consequences of their actions and know when enough is enough.

The Perceivers are mainly bottom brain perceivers and interpreters, but unlikely to initiate top brain detailed or complex plans.

Finally, the people with lazy top and bottom brains are ‘whatever…’ types, absorbed by local events and immediate imperatives, passively responsive to ongoing situations, i.e. the U.S. electorate.

Chapter 13 presents a test for the reader to determine his or her own individual style. They suggest that although you may not always rely on the same mode in every context, peoples' responses to the test indicate that they do operate in a single mode most of the time. You can take the test in the book, or take it online at www.TopBrainBottomBrain.com and have your score computed automatically.

Judging a man by the width of his face.

Valentine et al. make interesting observations in a speed-dating context. The effect of higher facial width-to-height ratio on short-term but not long-term relationships is compatible with the idea that more dominant men who are selected for mating because of their good health and prowess may also more likely to be less faithful and less investing as fathers:

Previous research has shown that men with higher facial width-to-height ratios (fWHRs) have higher testosterone and are more aggressive, more powerful, and more financially successful. We tested whether they are also more attractive to women in the ecologically valid mating context of speed dating. Men’s fWHR was positively associated with their perceived dominance, likelihood of being chosen for a second date, and attractiveness to women for short-term, but not long-term, relationships. Perceived dominance (by itself and through physical attractiveness) mediated the relationship between fWHR and attractiveness to women for short-term relationships. Furthermore, men’s perceptions of their own dominance showed patterns of association with mating desirability similar to those of fWHR. These results support the idea that fWHR is a physical marker of dominance. This is the first study to show that male dominance and higher fWHRs are attractive to women for short-term relationships in a controlled and interactive situation that could actually lead to mating and dating.

Over the hill at 24

Great....the continuous stream of papers documenting cognitive aging in adults and seniors, many noted in MindBlog, has how lowered the bar even further. Thompson et al. find a slowing of response times in a video game beginning at 24 years of age.

Typically studies of the effects of aging on cognitive-motor performance emphasize changes in elderly populations. Although some research is directly concerned with when age-related decline actually begins, studies are often based on relatively simple reaction time tasks, making it impossible to gauge the impact of experience in compensating for this decline in a real world task. The present study investigates age-related changes in cognitive motor performance through adolescence and adulthood in a complex real world task, the real-time strategy video game StarCraft 2. In this paper we analyze the influence of age on performance using a dataset of 3,305 players, aged 16-44, collected by Thompson, Blair, Chen & Henrey. Using a piecewise regression analysis, we find that age-related slowing of within-game, self-initiated response times begins at 24 years of age. We find no evidence for the common belief expertise should attenuate domain-specific cognitive decline. Domain-specific response time declines appear to persist regardless of skill level. A second analysis of dual-task performance finds no evidence of a corresponding age-related decline. Finally, an exploratory analyses of other age-related differences suggests that older participants may have been compensating for a loss in response speed through the use of game mechanics that reduce cognitive load.

Training emotions - a brief video from The Brain Club

I received an email recently from "The Brain Club" pointing me to the series of brief video presentations they are developing over time. I thought the presentation by Amit Etkin at Stanford Univ. was very effective. I'm including that video in this post. It describes the results of a meta-analysis of many papers that shows that in anxious and depressed individuals the brain's amygdala, insula, and cingulate are over-reactive while the prefrontal cortex is under-reactive. (i.e. the downstairs is over-riding the upstairs of our brains.) Cognitive training exercises available on the web that reinforce a positivity bias and enhance working memory lessen this upstairs/downstairs imbalance, and a brief review by Subramaniam and Vinogradov shows MRI data indicating that it is accompanied by enhancement of medial prefrontal activity.

 

Here is a slightly larger version of the figure from the meta-analysis paper showing the downstair (yellow) and upstairs (blue) regions whose activity changes with training.

A more through summary of cognitive training for impaired neural systems can be found in Vinogradov et al.

Attributing awareness to oneself and others.

Kelley et al. make some fascinating observations. I pass on their statement of the significance of the work and their abstract:

Significance

What is the relationship between your own private awareness of events and the awareness that you intuitively attribute to the people around you? In this study, a region of the human cerebral cortex was active when people attributed sensory awareness to someone else. Furthermore, when that region of cortex was temporarily disrupted, the person’s own sensory awareness was disrupted. The findings suggest a fundamental connection between private awareness and social cognition.

Abstract

This study tested the possible relationship between reported visual awareness (“I see a visual stimulus in front of me”) and the social attribution of awareness to someone else (“That person is aware of an object next to him”). Subjects were tested in two steps. First, in an fMRI experiment, subjects were asked to attribute states of awareness to a cartoon face. Activity associated with this task was found bilaterally within the temporoparietal junction (TPJ) among other areas. Second, the TPJ was transiently disrupted using single-pulse transcranial magnetic stimulation (TMS). When the TMS was targeted to the same cortical sites that had become active during the social attribution task, the subjects showed symptoms of visual neglect in that their detection of visual stimuli was significantly affected. In control trials, when TMS was targeted to nearby cortical sites that had not become active during the social attribution task, no significant effect on visual detection was found. These results suggest that there may be at least some partial overlap in brain mechanisms that participate in the social attribution of sensory awareness to other people and in attributing sensory awareness to oneself.