I couldn't resist passing this on from the I CAN HAS CHEEZ BURGER site:
Thursday, October 29, 2009
From Tranel, Adolphs, and collaborators, a fascinating piece of work reported in the International Journal of Psychology (check out the other articles in this issue, which has the theme 'Central and peripheral nervous system interactions: From mind to brain to body' Here is the abstract from their paper, followed by one table:
Does feeling an emotion require changes in autonomic responses, as William James proposed? Can feelings and autonomic responses be dissociated? Findings from cognitive neuroscience have identified brain structures that subserve feelings and autonomic response, including those induced by emotional music. In the study reported here, we explored whether feelings and autonomic responses can be dissociated by using music, a stimulus that has a strong capacity to induce emotional experiences. We tested two brain regions predicted to be differentially involved in autonomic responsivity (the ventromedial prefrontal cortex) and feeling (the right somatosensory cortex). Patients with damage to the ventromedial prefrontal cortex were impaired in their ability to generate skin-conductance responses to music, but generated normal judgments of their subjective feelings in response to music. Conversely, patients with damage to the right somatosensory cortex were impaired in their self-rated feelings in response to music, but generated normal skin-conductance responses to music. Control tasks suggested that neither impairment was due to basic defects in hearing the music or in cognitively recognizing the intended emotion of the music. The findings provide evidence for a double dissociation between feeling emotions and autonomic responses to emotions, in response to music stimuli.I thought the music clips they used to elicit emotional responses were interesting (click to enlarge):
By the way, here is another recent article by Salimpoor et al. on emotional arousal caused by music.
Angier does a summary.
Wednesday, October 28, 2009
Over the past month of unseasonably cold weather here in Middleton Wisconsin my movement has become increasingly stiff and arthritic, so today I am loading up the car and driving with my two abyssinian cats to Fort Lauderdale for the winter, unable to predict the frequency of posts for the next few days. The picture shows a Maple tree in my front yard.
Blog reader Gary Olson has pointed me to his review of Franz De Waal's new book
"The Age of Empathy: Nature’s Lessons For A Kinder Society." From that review:
de Waal provides compelling support for the proposition that humans are “preprogrammed to reach out.” From dolphins ferrying injured companions to safety and grieving elephants, baboons and cats (yes, even cats) to commiserating mice and hydrophobic chimps risking death to save a drowning companion, this is a major contribution to understanding the biological genesis of our inborn capacity for empathy, hence morality.
In seven crisply written and wholly accessible chapters de Waal methodically demolishes the rationale behind Gordon Gekko’s admonition in the film "Wall Street" that greed “captures the essence of the evolutionary spirit.”...De Waal objects to an unrestrained market system, not capitalism itself. He prefers that the economic system be mitigated by more attention to empathy in order to soften its rough edges...Nevertheless, de Waal seriously underestimates certain capitalist imperatives and the role played by elites in cultivating callousness, thereby undermining social solidarity, reciprocity and empathy. Capitalist culture devalues an empathic disposition, and, as Erich Fromm argued some fifty years ago, there is a basic incompatibility between the underlying principles of capitalism and the lived expression of an ethos of empathy.
Tuesday, October 27, 2009
Lewis et al. have demonstrated that learning an attention-demanding visual task modifies the spontaneous correlation of activity in the resting human brain - suggesting that the functional architecture of the brain is partly a product of previous experience. At left is a clay model representation of the human brain provided by Lewis, colored to indicate putative areas in frontal, temporal, and parietal cortex changed by a task. The abstract:
The brain is not a passive sensory-motor analyzer driven by environmental stimuli, but actively maintains ongoing representations that may be involved in the coding of expected sensory stimuli, prospective motor responses, and prior experience. Spontaneous cortical activity has been proposed to play an important part in maintaining these ongoing, internal representations, although its functional role is not well understood. One spontaneous signal being intensely investigated in the human brain is the interregional temporal correlation of the blood-oxygen level-dependent (BOLD) signal recorded at rest by functional MRI (functional connectivity-by-MRI, fcMRI, or BOLD connectivity). This signal is intrinsic and coherent within a number of distributed networks whose topography closely resembles that of functional networks recruited during tasks. While it is apparent that fcMRI networks reflect anatomical connectivity, it is less clear whether they have any dynamic functional importance. Here, we demonstrate that visual perceptual learning, an example of adult neural plasticity, modifies the resting covariance structure of spontaneous activity between networks engaged by the task. Specifically, after intense training on a shape-identification task constrained to one visual quadrant, resting BOLD functional connectivity and directed mutual interaction between trained visual cortex and frontal-parietal areas involved in the control of spatial attention were significantly modified. Critically, these changes correlated with the degree of perceptual learning. We conclude that functional connectivity serves a dynamic role in brain function, supporting the consolidation of previous experience.
Salient sounds such as those created by drumming can serve as means of nonvocal acoustic communication in addition to vocal sounds. Despite the ubiquity of drumming across human cultures, its origins and the brain regions specialized in processing such signals remain unexplored. Here, we report that an important animal model for vocal communication, the macaque monkey, also displays drumming behavior, and we exploit this finding to show that vocal and nonvocal communication sounds are represented by overlapping networks in the brain's temporal lobe. Observing social macaque groups, we found that these animals use artificial objects to produce salient periodic sounds, similar to acoustic gestures. Behavioral tests confirmed that these drumming sounds attract the attention of listening monkeys similarly as conspecific vocalizations. Furthermore, in a preferential looking experiment, drumming sounds influenced the way monkeys viewed their conspecifics, suggesting that drumming serves as a multimodal signal of social dominance. Finally, by using high-resolution functional imaging we identified those brain regions preferentially activated by drumming sounds or by vocalizations and found that the representations of both these communication sounds overlap in caudal auditory cortex and the amygdala. The similar behavioral responses to drumming and vocal sounds, and their shared neural representation, suggest a common origin of primate vocal and nonvocal communication systems and support the notion of a gestural origin of speech and music.
Characteristics of drumming sounds. (A) In this example, a macaque drums by firmly grasping the cage door with his forelimbs and shaking it vigorously and repeatedly. The inset displays the typical facial expression during drumming: open-mouth threatening, staring, forward directed pinnae. (B) Drumming sounds are acoustically distinct from typical vocalizations such as screams, grunts, or pant-threats. The repetitive beat pattern of the drumming sound produced by this action is visible in the time-frequency spectrum. The black line displays the power spectrum.
Monday, October 26, 2009
Several groups collaborate to show that meditation training can can significantly affect attention and brain function.
The capacity to stabilize the content of attention over time varies among individuals, and its impairment is a hallmark of several mental illnesses. Impairments in sustained attention in patients with attention disorders have been associated with increased trial-to-trial variability in reaction time and event-related potential deficits during attention tasks. At present, it is unclear whether the ability to sustain attention and its underlying brain circuitry are transformable through training. Here, we show, with dichotic listening task performance and electroencephalography, that training attention, as cultivated by meditation, can improve the ability to sustain attention. Three months of intensive meditation training reduced variability in attentional processing of target tones, as indicated by both enhanced theta-band phase consistency of oscillatory neural responses over anterior brain areas and reduced reaction time variability. Furthermore, those individuals who showed the greatest increase in neural response consistency showed the largest decrease in behavioral response variability. Notably, we also observed reduced variability in neural processing, in particular in low-frequency bands, regardless of whether the deviant tone was attended or unattended. Focused attention meditation may thus affect both distracter and target processing, perhaps by enhancing entrainment of neuronal oscillations to sensory input rhythms, a mechanism important for controlling the content of attention. These novel findings highlight the mechanisms underlying focused attention meditation and support the notion that mental training can significantly affect attention and brain function.
Stanton et al. collected saliva samples from 183 study participants before and after the results of the 2008 presidential election were announced. The results show that male Barack Obama voters (winners) had stable post-outcome testosterone levels, whereas testosterone levels dropped in male John McCain and Robert Barr (Libertarian candidate) voters (losers). There were no significant effects in female voters. These results were consistent with earlier studies showing testosterone decreases in male supporters of an athletic team after it loses a game.
Friday, October 23, 2009
Tamietto et al. make the fascinating observation that unseen emotionally expressive facial or body movements (stimuli presented to the blind portion of the visual field of patients with damage to their visual cortex) cause arousal and facial reactions. They suggest that emotional contagion represents affective reactions mediated by visual pathways of old evolutionary origin that bypass cortical vision and allow emotion communication and affect sharing. Here is their abstract:
The spontaneous tendency to synchronize our facial expressions with those of others is often termed emotional contagion. It is unclear, however, whether emotional contagion depends on visual awareness of the eliciting stimulus and which processes underlie the unfolding of expressive reactions in the observer. It has been suggested either that emotional contagion is driven by motor imitation (i.e., mimicry), or that it is one observable aspect of the emotional state arising when we see the corresponding emotion in others. Emotional contagion reactions to different classes of consciously seen and “unseen” stimuli were compared by presenting pictures of facial or bodily expressions either to the intact or blind visual field of two patients with unilateral destruction of the visual cortex and ensuing phenomenal blindness. Facial reactions were recorded using electromyography, and arousal responses were measured with pupil dilatation. Passive exposure to unseen expressions evoked faster facial reactions and higher arousal compared with seen stimuli, therefore indicating that emotional contagion occurs also when the triggering stimulus cannot be consciously perceived because of cortical blindness. Furthermore, stimuli that are very different in their visual characteristics, such as facial and bodily gestures, induced highly similar expressive responses. This shows that the patients did not simply imitate the motor pattern observed in the stimuli, but resonated to their affective meaning. Emotional contagion thus represents an instance of truly affective reactions that may be mediated by visual pathways of old evolutionary origin bypassing cortical vision while still providing a cornerstone for emotion communication and affect sharing.
Having to live more lean and mean in economically hard times is apparently good for us. From Granados and Roux:
Recent events highlight the importance of examining the impact of economic downturns on population health. The Great Depression of the 1930s was the most important economic downturn in the U.S. in the twentieth century. We used historical life expectancy and mortality data to examine associations of economic growth with population health for the period 1920–1940. We conducted descriptive analyses of trends and examined associations between annual changes in health indicators and annual changes in economic activity using correlations and regression models. Population health did not decline and indeed generally improved during the 4 years of the Great Depression, 1930–1933, with mortality decreasing for almost all ages, and life expectancy increasing by several years in males, females, whites, and nonwhites. For most age groups, mortality tended to peak during years of strong economic expansion (such as 1923, 1926, 1929, and 1936–1937). In contrast, the recessions of 1921, 1930–1933, and 1938 coincided with declines in mortality and gains in life expectancy. The only exception was suicide mortality which increased during the Great Depression, but accounted for less than 2% of deaths. Correlation and regression analyses confirmed a significant negative effect of economic expansions on health gains. The evolution of population health during the years 1920–1940 confirms the counterintuitive hypothesis that, as in other historical periods and market economies, population health tends to evolve better during recessions than in expansions.
The 150th issue of the British Psychological Association's Research Digest email has posted a series of fascinating responses by leading psychologists to the request that they look inwards and share, in 150 words, one nagging thing they still don't understand about themselves.
Thursday, October 22, 2009
Here is a neat graphic from the New York Times, apparently motivated by a paper this month in The Lancet saying that half of all the babies born in developed countries in 2007 will live to be 104. This suggests the addition of a 4th life stage, "Old old age" to current categories of youth, adulthood, and old age. The graphic depicts the stages of life as viewed in different historical eras by a variety of writers.
David Brooks does a nice layman's summary titled "Where the Wild Things Are" of our modern views on how an individual's 'character' is composed - not from the top down by a single unifying feature, but rather from a pandora's box of possible selves, each of which can appear under a particular set of circumstances.
Wednesday, October 21, 2009
Engber writes a brief article on the fact that not only are there correlations between excess fat and health risk, but also shorter height correlates with increased coronary heart disease, diabetes or stroke. Also,
In the labor market, the effects of height and weight tend to run in parallel. A 2004 study by John Cawley of Cornell University found that severely obese white women who weigh more than two standard deviations above average — women who weigh, for example, more than 212 pounds if they’re 5 feet 4 inches tall — are paid up to 9 percent less for their work. Likewise, a decrease in a man’s height to the 25th percentile from the 75th — roughly to 5 feet 8 inches from 6 feet— is associated with, on average, a dip in earnings of 6 to 10 percent...And like obese people, short people are less likely to finish college than those of average weight. A paper from the July issue of the journal Economics and Human Biology used survey data from more than 450,000 adults to conclude that male college graduates are, on average, more than an inch taller than men who never finished high school.
This work from Dickerson et al. is both fascinating and frightening. It provides a more detailed glimpse of how social threat can transmute into self-destructive body chemistry.
This study experimentally tested whether a stressor characterized by social-evaluative threat (SET), a context in which the self can be judged negatively by others, would elicit increases in proinflammatory cytokine activity and alter the regulation of this response. This hypothesis was derived in part from research on immunological responses to social threat in nonhuman animals. Healthy female participants were assigned to perform a speech and a math task in the presence or absence of an evaluative audience (SET or non-SET, respectively). As hypothesized, stimulated production of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) increased from baseline to poststressor in the SET condition, but was unchanged in the non-SET condition. Further, the increases in TNF-α production correlated with participants' cognitive appraisals of being evaluated. Additionally, the ability of glucocorticoids to shut down the inflammatory response was decreased in the SET condition. These findings underscore the importance of social evaluation as a threat capable of eliciting proinflammatory cytokine activity and altering its regulation.
From Davis et al.:
The generalist genes hypothesis implies that general cognitive ability (g) is an essential target for understanding how genetic polymorphisms influence the development of the human brain. Using 8,791 twin pairs from the Twins Early Development Study, we examine genetic stability and change in the etiology of g assessed by diverse measures during the critical transition from early to middle childhood. The heritability of a latent g factor in early childhood is 23%, whereas shared environment accounts for 74% of the variance. In contrast, in middle childhood, heritability of a latent g factor is 62%, and shared environment accounts for 33%. Despite increasing importance of genetic influences and declining influence of shared environment, similar genetic and shared environmental factors affect g from early to middle childhood, as indicated by a cross-age genetic correlation of .57 and a shared environmental correlation of .65. These findings set constraints on how genetic and environmental variation affects the developing brain.
Tuesday, October 20, 2009
Johan Leher has contributed a fascinating article to Nature News (PDF here) that discusses the 30 or more strains of mice that have been genetically altered to have enhanced memory and problem solving capabilities, and more generally addresses the issue of cognitive enhancement in humans. Many of the mouse mutants have enhanced long term potentiation (LTP) at synapses (a few nerve transmissions between nerve cells enhance further transmissions). LTP is a fundamental feature of learning and memory, and it appears that by increasing its plasticity it is possible to increase cognitive capacity.
The downside of enhancing memory, at least in some unusual humans who have extraordinary memory abilities, is that they appear to be locked in details, unable to understand metaphors or generalize. Martha Farah notes that some human experiments with amphetamines show a trade-off between enhanced attention and performance on creative tasks. "The brain may have made a compromise in that having a more accurate memory interferes with the ability to generalize...You may need a little noise in order to be able to think abstractly, to get beyond the concrete and literal." A further issue is non-cognitive side effects, which have been demonstrated in mice, such as enhanced sensitivity to pain.
Posted by Deric Bownds at 5:30 AM
An interesting article from Livingston and Pearce, "The Teddy-Bear Effect: Does Having a Baby Face Benefit Black Chief Executive Officers?" The abstract:
Prior research suggests that having a baby face is negatively correlated with success among White males in high positions of leadership. However, we explored the positive role of such "babyfaceness" in the success of high-ranking Black executives. Two studies revealed that Black chief executive officers (CEOs) were significantly more baby-faced than White CEOs. Black CEOs were also judged as being warmer than White CEOs, even though ordinary Blacks were rated categorically as being less warm than ordinary Whites. In addition, baby-faced Black CEOs tended to lead more prestigious corporations and earned higher salaries than mature-faced Black CEOs; these patterns did not emerge for White CEOs. Taken together, these findings suggest that babyfaceness is a disarming mechanism that facilitates the success of Black leaders by attenuating stereotypical perceptions that Blacks are threatening. Theoretical and practical implications for research on race, gender, and leadership are discussed.
Monday, October 19, 2009
Ross Douthat reviews a book, "The Case for God" by Karen Armstrong, that tries to land somewhere between the militant atheists and the religious fundamentalists. Armstrong makes a case for an approach to religion:
...which emphasizes the pursuit of an unknowable Deity, rather than the quest for theological correctness ... compatible with a liberal, scientific, technologically advanced society. She argues that it’s actually truer to the ancient traditions of Judaism, Islam and (especially) Christianity than is much of what currently passes for “conservative” religion. And the neglect of these traditions, she suggests, is “one of the reasons why so many Western people find the concept of God so troublesome today.”
Both modern believers and modern atheists, Armstrong contends, have come to understand religion primarily as a set of propositions to be assented to, or a catalog of specific facts about the nature of God, the world and human life. But this approach to piety would be foreign to many premodern religious thinkers, including the greatest minds of the Christian past, from the early Fathers of the Church to medieval eminences like Thomas Aquinas.
These and other thinkers, she writes, understood faith primarily as a practice, rather than as a system — not as “something that people thought but something they did.” Their God was not a being to be defined or a proposition to be tested, but an ultimate reality to be approached through myth, ritual and “apophatic” theology, which practices “a deliberate and principled reticence about God and/or the sacred” and emphasizes what we can’t know about the divine. And their religion was a set of skills, rather than a list of unalterable teachings — a “knack,” as the Taoists have it, for navigating the mysteries of human existence.
Many cognitive neuroscience measurements are made on subjects who are supine, as for example in an MRI scanner. Given that body postures can affect behaviors (as when slumped postures lead to more 'helpless' behaviors, or erect posture with chest protruding enhances confident behavior) Harmon-Jones and Peterson compared the brain responses of subjects to anger-inducing insults while in either an upright or reclined position . It is know that left prefrontal cortex is more activated than the right prefrontal cortex during the experience of anger, particularly anger associated with approach motivational inclinations. They found, consistent with an embodied motivation prediction, that a insult delivered to subjects in an upright condition produced greater relative left lateral frontal activity than insults in a reclined condition - which produced about the same relative left lateral frontal activity as the neutral-upright condition.
Friday, October 16, 2009
John Cassidy, in an interesting article in The New Yorker, discusses the inner logic of an economy like ours, in which behavior that is perfectly reasonable on the individual level produces calamity when aggregated in the marketplace. During both rises and falls in the markets, very small perturbations can be magnified by interlocking feedback loops that cause the economy to balloon into either a bubble or a crash.
Calvin Trillin, in a humorous but dead-on piece, has a much more simple model for the meltdown. Wall Street used to be run by the bottom third of the college class, the people who took gut general education courses (such as the Geology course referred to as "Rocks for Jocks"), and they weren't smart enough to invent all these fancy derivative investment vehicles. Then the upper third of the class that used to become teachers, doctors, or lawyers decided they needed to make more money. Mathematicians and physicists poured in to investment houses and invented all the complicated and sophisticated schemes that brought down the system.
An interesting bit from IJzerman and Semin, who examine the effect of warmth on social proximity:
"Holding warm feelings toward someone" and "giving someone the cold shoulder" indicate different levels of social proximity. In this article, we show effects of temperature that go beyond these metaphors people live by. In three experiments, warmer conditions, compared with colder conditions, induced (a) greater social proximity, (b) use of more concrete language, and (c) a more relational focus. Different temperature conditions were created by either handing participants warm or cold beverages (Experiment 1) or placing them in comfortable warm or cold ambient conditions (Experiments 2 and 3). These studies corroborate recent findings in the field of grounded cognition revealing that concrete experiences ground abstract concepts with which they are coexperienced. Our studies show a systemic interdependence among language, perception, and social proximity: Environmentally induced conditions shape not only language use, but also the perception and construal of social relationships.
Thursday, October 15, 2009
I've done a number of posts on the evils of multitasking (for example here and here, or enter multitasking in the search box in the left column of this blog), and thus was struck by a number of salient points in an article by Perri Klass. Here are some clips:
...A recent and much-discussed study showed decreased productivity in adults who were multitasking...you don’t really multitask, you just think you do; the brain can’t process two high-level cognitive things. What you are actually doing...is oscillating between the two...So are teenagers any better at oscillating?...It may be that multitasking is more of a problem for us old brains...parents are digital immigrants...children are digital natives...they really have come of age with these technologies.One possibility is that performing a task while allowing distractions lengthens the amount of time that can be spent on the task, more than compensating for a decrease in efficiency.
The literature looking at media and its impact on attentional skills is just in its infancy...We don’t really know what they pay attention to, what they don’t. We don’t know how it impacts their school performance, whether it impacts their school performance.
Patricia Cohen offers a review of Barbara Ehrenreich's new book “Bright-sided: How the Relentless Promotion of Positive Thinking Has Undermined America,” which takes on the happiness movement, in particular its more extreme proponents. The book, despite its title, it is not a curmudgeonly rant. Ehrenreich found in 2000 that she had breast cancer. The book chronicles:
...her stay in a world that she became intimately familiar with: the smiley-faced, pink-ribboned, positive-thinking culture that surrounds breast cancer patients...The unrelenting message was “that you had to be cheerful and accepting and that you would not recover unless you were...It’s a clever blame-the-victim sort of thing.”
Then the financial crisis hit. “Wham,” she said. “It was so clear to me that it was connected.” The relentlessly optimistic forecasts about subprime mortgages and endless increases in real estate values were the product of the positive-thinking culture. One of the fundamental tenets of the literature, Ms. Ehrenreich said, is to surround yourself with other positive thinkers and “get rid of negative people...
We’ve been weeding out anybody capable of rational thinking, of realism.”
In “Bright-sided,” she traces the roots of the nation’s blithe sunniness to a reaction against Calvinist gloom and the limits of medical science in the first half of the 19th century. Starting with Phineas Parkhurst Quimby, perhaps one of the first American New Age faith healers, she draws a line to Mary Baker Eddy, the founder of Christian Science; the psychologist William James; Ralph Waldo Emerson; Norman Vincent Peale, who published “The Power of Positive Thinking” in 1952; and the toothy television minister Joel Osteen, who preaches the gospel of prosperity...To Ms. Ehrenreich, the reliance on one’s personal disposition shifts attention from the larger social, political and economic forces behind poverty, unemployment and poor health care. “It can’t all be fixed by assertiveness training...All that shiny optimism, she said, was “like sitting in a warm bubble bath for too long.”
Wednesday, October 14, 2009
Here is a figure from a neat article (PDF here) by Richard Russell illustrating how facial contrast and cosmetics can alter the perceived sex of an androgynous face.
The Illusion of Sex. The face on the left appears male, while the face on the right appears female. Both images were produced by making slight alterations to the same original image. The eyes and lips were unaltered, and hence equally dark in both images. The remainder of the image was darkened to produce the left image, and lightened to produce the right image. The eyes and lips may appear darker in the right image than in the left image, but are notöit is an example of simultaneous contrast.
Sam Harris (the guy who wrote "The End of Faith" and "Letters to a Christian Nation"), along with a group of collaborators, has made fMRI measurements on fifteen committed Christians and fifteen nonbelievers as they evaluated the truth and falsity of religious and nonreligious propositions. Religious thinking is more associated with brain regions that govern emotion, self-representation, and cognitive conflict, while thinking about ordinary facts is more reliant upon memory retrieval networks.
Tuesday, October 13, 2009
Carré et al. find that observers can make accurate judgments of propensity for aggression in men from faces displaying neutral expressions, even when exposure to the faces is limited to 39 ms. Individual participants reliably judged men with larger facial width to height ratios as more aggressive. Here is their abstract and a figure from the paper showing the width and height determination:
Facial width-to-height ratio is a sexually dimorphic metric that is independent of body size and may have been shaped by sexual selection. We recently showed that this metric is correlated with behavioral aggression in men. In Study 1, observers estimated the propensity for aggression of men photographed displaying neutral facial expressions and for whom a behavioral measure of aggression was obtained. The estimates were correlated strongly with the facial width-to-height ratio of the stimulus faces and with the actual aggression of the men. These results were replicated in Study 2, in which the exposure to each stimulus face was shortened to 39 ms. Participants' estimates of aggression for each stimulus face were highly correlated between Study 2 (39-ms exposure) and Study 1 (2,000-ms exposure). These findings suggest that the facial width-to-height ratio may be a cue used to predict propensity for aggression in others.
This recent work from Schultz, Dolan and collaborators suggests brain imaging might be able to predict risky versus safe behaviors in a given choice context:
Decision making under risk is central to human behavior. Economic decision theory suggests that value, risk, and risk aversion influence choice behavior. Although previous studies identified neural correlates of decision parameters, the contribution of these correlates to actual choices is unknown. In two different experiments, participants chose between risky and safe options. We identified discrete blood oxygen level-dependent (BOLD) correlates of value and risk in the ventral striatum and anterior cingulate, respectively. Notably, increasing inferior frontal gyrus activity to low risk and safe options correlated with higher risk aversion. Importantly, the combination of these BOLD responses effectively decoded the behavioral choice. Striatal value and cingulate risk responses increased the probability of a risky choice, whereas inferior frontal gyrus responses showed the inverse relationship. These findings suggest that the BOLD correlates of decision factors are appropriate for an ideal observer to detect behavioral choices. More generally, these biological data contribute to the validity of the theoretical decision parameters for actual decisions under risk.
Monday, October 12, 2009
An article by Pauline C. Ng, Sarah S. Murray, Samuel Levy and J. Craig Venter finds differences in results from two direct to consumer genetics testing companies. Their summary:
* For seven diseases, 50% or less of the predictions of two companies agreed across five individualsAlso Lahn and Ebenstein argue that the discovery of genetic diversity among groups of people as well as among individuals should be embraced, not feared. Their summary:
* Companies should communicate high risks better and test for drug response markers
* Community should study markers in all ethnicities and look at behaviour after tests
* Promoting biological sameness in humans is illogical, even dangerous
* To ignore the possibility of group diversity is to do poor science and poor medicine
* A robust moral position is one that embraces this diversity as among humanity's great assets
It is often assumed that critical periods exist for the development of vision and other neural capabilities and that they end prior to adolescence. For example, it might be expected that gene therapy in adults with congenital vision disorders would be impossible. But experiments in adult spider monkeys who are normally red–green colour blind show that it is possible to add a third photopigment (human opsin) into some of their retinal cells by gene therapy. The monkeys acquire a new dimension of colour vision as a result. Not only does this suggest a possible therapy for a common congenital visual defect in humans (clinical trials are now under way), but also it demonstrates the extreme neuroplasticity of visual processing and points to possible routes by which trichromatic vision evolved.
Friday, October 09, 2009
Benedict Carey points to an article in Psychological Science that I scanned past without realizing its interest. Proulx and Heine show that a threat to our sense of coherence or meaning in one area (such as reading an absurd short story by Kafka) enhances our ability to unconsciously detect patterns within letter strings (an artificial grammar task). Encountering incoherence apparently primes our brains to detect patterns they might otherwise miss. The idea is that the brain evolved to predict, and it does so by identifying patterns. The process is enhanced by a threat to meaning. (It is also important to evaluate the possibility that nervousness, not a search for meaning, leads to heightened vigilance.)
Another gem from the Random Samples section of the Oct. 2 Science Magazine:
Frank Rühli wants to know just how the Egyptians did it. So he is trying to mummify human legs.
Rühli, a physician and head of the Swiss Mummy Project at the University of Zurich, and his collaborators severed the legs from a female donor body. One, the "control leg," was kept in an oven at 40°C and low humidity to replicate "natural mummification" in the Egyptian desert. The other leg, as described in ancient Egyptian records, was put on a pine board and covered with natron, a blend of four sodium compounds that pulls moisture out of the tissue. The researchers left it at 23°C to see what natron would do in the Swiss environment.
Other researchers have tried mummifying human remains. But the Swiss group is using advanced imaging technology, biopsies, and tests of DNA degradation for moment-by-moment analysis of the mummification process.
So far, the researchers have found that mummification in Zurich takes longer than expected: After 3 months, scans showed that the natron leg still had pockets of humidity, Rühli says. They have also discovered that storing an untreated leg in the heat doesn't work well. The control leg failed to dry out and started to decompose after a week. Rühli plans to repeat the experiment, this time encasing the control leg in hot sand.
Thursday, October 08, 2009
From Chib et al.:
To make economic choices between goods, the brain needs to compute representations of their values. A great deal of research has been performed to determine the neural correlates of value representations in the human brain. However, it is still unknown whether there exists a region of the brain that commonly encodes decision values for different types of goods, or if, in contrast, the values of different types of goods are represented in distinct brain regions. We addressed this question by scanning subjects with functional magnetic resonance imaging while they made real purchasing decisions among different categories of goods (food, nonfood consumables, and monetary gambles). We found activity in a key brain region previously implicated in encoding goal-values: the ventromedial prefrontal cortex (vmPFC) was correlated with the subjects' value for each category of good. Moreover, we found a single area in vmPFC to be correlated with the subjects' valuations for all categories of goods. Our results provide evidence that the brain encodes a "common currency" that allows for a shared valuation for different categories of goods.
Many training programs for clinical psychologists in the United States should be scrapped, an organization of psychologists says. In a report to be released this month, the Association for Psychological Science (APS) calls for more scientific rigor in psychotherapy. "Clinical psychology resembles medicine at a point in its history when practitioners were operating in a largely prescientific manner," it says. Therapists' "lack of adequate science training ... leads them to value personal clinical experience over research evidence." The report lambastes the American Psychological Association (APA)—which comprises mainly clinical psychologists—for lax accreditation standards and proposes a new mechanism for certifying Ph.D. training programs.
Psychologist Scott Lilienfeld of Emory University in Atlanta praises the report, saying, "Far too many practitioners are administering unsubstantiated or untested intervention." But he worries that its proposals would freeze out Psy.D. programs, nonresearch degrees begun in the 1970s, which now turn out about half of the nation's clinical psychologists.
Jeffrey Zeig, a clinical psychologist and director of the Milton H. Erikson Foundation in Phoenix, says psychotherapy is much too diverse to be constrained by APS definitions. "There are more than 1,000,000 therapists in the U.S., and only a fraction" have Ph.D.s, says Zeig, who predicts the report "will have as much effect as a breeze has on a leaf."
But report co-author Timothy Baker of the University of Wisconsin School of Medicine and Public Health in Madison predicts that it "will ultimately reshape clinical psychology just as the  Flexner Report reshaped medicine," leading to the closure of almost half the nation's medical schools.
My partner and I live in Madison, Wisconsin. The state legislature recently passed a bill granting domestic partnerships a small fraction of the benefits that go with conventional marriage (like being able to visit your ill partner in the hospital, or by default have health care or legal power of attorney if one partner is incapacitated.) This bill is being challenged in court by the same right wing religious nuts who backed the successful drive to add a state constitutional amendment banning gay marriage. I've become acutely aware of some of the financial downside of being a gay couple over the past 20 years of my current partnership, having been in a conventional marriage for 21 years before that. Now some hard numbers on just how unfair the situation is have been generated by Bernard and Lieber in the New York Times. The lifetime penalty for being in a same-sex couple can range between ~$30,000 and ~$200,000, depending on the circumstance.
Wednesday, October 07, 2009
As a companion to the previous post on distinguishing 'wanting' and 'liking' I would like to point you to an engaging article in Slate by Emily Yoffe (thanks to my son Jon for pointing it out to me). She discusses the work from researchers like Jaak Panksepp and Kent Berridge (the subjects of several mindblog posts over the past few years) that suggests the biological basis of our addiction to email, google, twitter, texting, etc.
The juice that fuels the seeking system is the neurotransmitter dopamine. The dopamine circuits "promote states of eagerness and directed purpose," Panksepp writes. It's a state humans love to be in. So good does it feel that we seek out activities, or substances, that keep this system aroused—cocaine and amphetamines, drugs of stimulation, are particularly effective at stirring it.
Ever find yourself sitting down at the computer just for a second to find out what other movie you saw that actress in, only to look up and realize the search has led to an hour of Googling? Thank dopamine. Our internal sense of time is believed to be controlled by the dopamine system. People with hyperactivity disorder have a shortage of dopamine in their brains, which a recent study suggests may be at the root of the problem. For them even small stretches of time seem to drag. An article by Nicholas Carr in the Atlantic last year, "Is Google Making Us Stupid?" speculates that our constant Internet scrolling is remodeling our brains to make it nearly impossible for us to give sustained attention to a long piece of writing. Like the lab rats, we keep hitting "enter" to get our next fix.
Wanting is Berridge's equivalent for Panksepp's seeking system. It is the liking system that Berridge believes is the brain's reward center. When we experience pleasure, it is our own opioid system, rather than our dopamine system, that is being stimulated. This is why the opiate drugs induce a kind of blissful stupor so different from the animating effect of cocaine and amphetamines. Wanting and liking are complementary. The former catalyzes us to action; the latter brings us to a satisfied pause. Seeking needs to be turned off, if even for a little while, so that the system does not run in an endless loop. When we get the object of our desire (be it a Twinkie or a sexual partner), we engage in consummatory acts that Panksepp says reduce arousal in the brain and temporarily, at least, inhibit our urge to seek.
But our brains are designed to more easily be stimulated than satisfied. "The brain seems to be more stingy with mechanisms for pleasure than for desire," Berridge has said. This makes evolutionary sense. Creatures that lack motivation, that find it easy to slip into oblivious rapture, are likely to lead short (if happy) lives. So nature imbued us with an unquenchable drive to discover, to explore. Stanford University neuroscientist Brian Knutson has been putting people in MRI scanners and looking inside their brains as they play an investing game. He has consistently found that the pictures inside our skulls show that the possibility of a payoff is much more stimulating than actually getting one.
Actually all our electronic communication devices—e-mail, Facebook feeds, texts, Twitter—are feeding the same drive as our searches. Since we're restless, easily bored creatures, our gadgets give us in abundance qualities the seeking/wanting system finds particularly exciting. Novelty is one. Panksepp says the dopamine system is activated by finding something unexpected or by the anticipation of something new. If the rewards come unpredictably—as e-mail, texts, updates do—we get even more carried away. No wonder we call it a "CrackBerry."
Work from Berridge and collaborators shows in rat experiments that pathways in the ventral pallidum that fire when a cue to a previously liked stimulus (such as sucrose) is presented - but do not fire with a cue of the previously "disliked" taste of intense salt - can suddenly become activated if the salt cue is encountered in a never-before-experienced state of physiological salt depletion. This means that dynamic recomputation of cue-triggered "wanting" signals can occur in real time at the moment of cue re-encounter by combining a previously learned Pavlovian associations with novel physiological information about a current state of specific appetite.
Tuesday, October 06, 2009
Nicholas Wade notes a recent meeting on aging at Harvard Medical School (Some of the participants belong to the "120 Club," whose members propose to live until they are 120). His article focuses on work of David Sinclair and Sirtris Pharmaceuticals .
...In mice, sirtuin activators are effective against lung and colon cancer, melanoma, lymphoma, Type 2 diabetes, cardiovascular disease and Alzheimer’s disease...SRT-501, the company’s special formulation of resveratrol, is being tested against two cancers, multiple myeloma and colon cancer that has spread to the liver. A chemical mimic of resveratrol, known as SRT-2104, is in a Phase 2 trial for Type 2 diabetes, and in a Phase 1 trial in elderly patients. (Phase 1 trials test for safety, Phase 2 for efficacy.)...unpublished tests in mice showed that another chemical mimic, SRT-1720, increased both health and lifespan; after two years, twice as many mice taking the drug were alive compared with the undosed animals. Resveratrol itself has not been shown to increase lifespan in normal mice, although it does so in obese mice, laboratory roundworms and flies.
Mobbs et al. show that higher forebrain areas are involved in early-threat responses, including the assignment and control of fear, whereas imminent danger results in fast more "hard-wired" defensive reactions mediated by our midbrain.
Monday, October 05, 2009
An interesting report from Longo et al. :
Given previous reports of strong interactions between vision and somatic senses, we investigated whether vision of the body modulates pain perception. Participants looked into a mirror aligned with their body midline at either the reflection of their own left hand (creating the illusion that they were looking directly at their own right hand) or the reflection of a neutral object. We induced pain using an infrared laser and recorded nociceptive laser-evoked potentials (LEPs). We also collected subjective ratings of pain intensity and unpleasantness. Vision of the body produced clear analgesic effects on both subjective ratings of pain and the N2/P2 complex of LEPs. Similar results were found during direct vision of the hand, without the mirror. Furthermore, these effects were specific to vision of one's own hand and were absent when viewing another person's hand. These results demonstrate a novel analgesic effect of non-informative vision of the body.
de Bruijn et al. show a clear distinction between error and reward processing in our brains:
For social beings like humans, detecting one's own and others' errors is essential for efficient goal-directed behavior. Although one's own errors are always negative events, errors from other persons may be negative or positive depending on the social context. We used neuroimaging to disentangle brain activations related to error and reward processing, by manipulating the social context (cooperation or competition). Activation in posterior medial frontal cortex (pMFC) was increased for all errors, independent of who made the error or the reward outcome. Conversely, activity in striatum was modulated by reward, independent of whether the action was erroneous or not. The results demonstrate a clear distinction between error and reward processing in the human brain. Importantly, the current study indicates that error detection in pMFC is independent of reward and generalizes beyond our own actions, highlighting its role in optimizing performance in both individual and joint action.
There is an engaging article by Henig in yesterday's New York Times Magazine: "Understanding the anxious mind." It focuses on the famous work of Jerome Kagan at Harvard; who, along with others, has shown that some of us are born with a predisposition to be timid and anxious.
Friday, October 02, 2009
Work from Takashima et al. confirms the idea that the retrieval network for memories shifts away from using the hippocampus as the memories grow older and are consolidated in the neocortex. They use MRI measurement to observe this shift:
The standard model of system-level consolidation posits that the hippocampus is part of a retrieval network for recent memories. According to this theory, the memories are gradually transferred to neocortical circuits with consolidation, where the connections within this circuit grow stronger and reorganized so that redundant and/or contextual details may be lost. Thus, remote memories are based on neocortical networks and can be retrieved independently of the hippocampus. To test this model, we measured regional brain activity and connectivity during retrieval with functional magnetic resonance imaging. Subjects were trained on two sets of face–location association and were tested with two different delays, 15 min and 24 h including a whole night of sleep. We hypothesized that memory traces of the locations associated with specific faces will be linked through the hippocampus for the retrieval of recently learned association, but with consolidation, the activity and the functional connectivity between the neocortical areas will increase. We show that posterior hippocampal activity related to high-confidence retrieval decreased and neocortical activity increased with consolidation. Moreover, the connectivity between the hippocampus and the neocortical regions decreased and in turn, cortico-cortical connectivity between the representational areas increased. The results provide mechanistic support for a two-level process of the declarative memory system, involving initial representation of new associations in a network including the hippocampus and subsequent consolidation into a predominantly neocortical network.
Another compilation of items that are potentially interesting to some MindBlog readers:
Two Blogs of interest: Body in Mind (self explanatory) and Phenomics (on more intelligent description of personality dysfunction based on underlying genetic heterogeneity, and how the the Diagnostic and Statistical Manual of Mental Disorders actually impedes research and understanding.)
The robot that breaks and reassembles itself.
Why we need God. From Robert Wright, author of “The Moral Animal,” “Nonzero” and, most recently, “The Evolution of God.”
Eyes Wide Shut - perceived emotionality of music, eye closure, and the amygdala.
Brain pathology in athletes appears at an unusually young age.
Numbers in the Blind's “Eye.” Both blind and sighted people represent numbers through a spatial code, but with different electrophysiological correlates corresponding to cognitive versus sensory processing.
Gates Puts Feynman Lectures Online. These famous lectures can show you that there really is joy in physics. I was overwhelmed when I first saw some of them in my college days.
Knowledge rewards. It turns out that the size of coming rewards is signalled by the same dopamine neurons that signal primitive rewards like sex and food. Two monkeys were trained to glance at one of two targets on a computer screen in order to receive a drink reward, which was randomly large or small. When one target included information about reward size the monkeys preferred to go for that target, rather than be surprised by a randomly sized reward. Neurons in the brain's 'reward' circuitry fired when the monkeys learned information about the future, suggesting that the act of prediction may be intrinsically rewarding.
Yet another theory on why we sleep ...suggestion that sleep evolved to optimize animals’ use of time, keeping them safe and hidden when the hunting, fishing or scavenging was scarce and perhaps risky. In that view, differences in sleep quality, up to and including periods of insomnia, need not be seen as problems but as adaptations to the demands of the environment.
Thursday, October 01, 2009
A fundamental building block in shaping our behavior is the relationship between a sensory event, a chosen action and its consequences. Histed et al. now point to how the brain stores this information by showing that neurons in the monkey prefrontal cortex and basal ganglia display persistent activity that is related to the outcomes of previous actions. Seo and Lee review this work in Nature, noting in the figure the sort of stimulus, action, outcome sequence that is in question :
Basically, the data suggest that the prefrontal cortex and basal ganglia might be essential brain areas for storing information about action–outcome associations
Placement of Asperger syndrome within the family of autism spectrum disorders (ASD) has always been a bit uneasy; although people with Asperger syndrome do exhibit the core impairments in social interaction and communication that are characteristic of ASD, they nevertheless perform well on tests that are thought to assess the ability to mentalize or to possess Theory of Mind skills. One of the classic tests of mentalizing ability is the false-belief task, in which subjects must be able to represent their own beliefs (true) and another's beliefs, which are false because they have not been given complete information, such as not having seen the transfer of a piece of candy from one drawer to another. People with Asperger syndrome succeed at the verbal form of the false-belief task, yet Senju et al. show that this is owing entirely to their having learned how to cope with an existing and still demonstrable deficit in an implicit version of the false-belief task. That is, the core impairment is present, but conscious and explicit learning allows them to compensate.Here is the Senju et al. abstract:
Adults with Asperger syndrome can understand mental states such as desires and beliefs (mentalizing) when explicitly prompted to do so, despite having impairments in social communication. We directly tested the hypothesis that such individuals nevertheless fail to mentalize spontaneously. To this end, we used an eye-tracking task that has revealed the spontaneous ability to mentalize in typically developing infants. We showed that, like infants, neurotypical adults’ (n = 17 participants) eye movements anticipated an actor’s behavior on the basis of her false belief. This was not the case for individuals with Asperger syndrome (n = 19). Thus, these individuals do not attribute mental states spontaneously, but they may be able to do so in explicit tasks through compensatory learning.