Friday, April 09, 2010

Brain correlates of anticipation and body dysmorphic disorder

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

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

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

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

Thursday, April 08, 2010

fMRI measurents distinguish specific memories

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

Wednesday, April 07, 2010

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

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

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

Unconscious control of 'conscious' prefrontal cognitive control.

Unconscious information has been shown to influence motivation, reward value and decision making, emotional processing, object recognition, semantic processing, and action planning/execution. Van Gaal et al. now look for evidence of unconscious cognitive control. From their text and the abstract:
Cognitive control becomes necessary when routine behavior (e.g., driving a car) is interrupted unexpectedly by information (e.g., a 'no-go' stimulus such as a pedestrian crossing the street) that calls for behavioral adaptations (e.g., braking fiercely). Generally speaking, it is thought that one should be conscious of the control-initiating stimulus to implement control and to overcome or to inhibit automatized ongoing behavior ("to regain control"). The recruitment and implementation of such control processes depend strongly on the prefrontal cortex (PFC), which is, of all brain regions, also the one most often associated with conscious experience. Therefore, it seems likely that consciousness and cognitive control are intimately related and this belief is so strong that many authors naturally refer to the concept of "conscious cognitive control" as if "unconscious cognitive control" is inconceivable.

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


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

Tuesday, April 06, 2010

The love that dare not squawk its name.

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

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

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

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

Monday, April 05, 2010

A new wave in literary studies - theories of mind

Patricia Cohen writes an article on a new trend in the musty hallways of university English departments,  trying to unite cognitive psychology and literary criticism.  Here are some slightly edited clips:
Why do we read fiction? Why do we care so passionately about nonexistent characters? What underlying mental processes are activated when we read? ...The layered process of figuring out what someone else is thinking — of mind reading — is both a common literary device and an essential survival skill. This capacity is termed 'theory of mind' by cognitive psychologists.

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

Friday, April 02, 2010

A Mozart presto

Final movement of the Mozart from Monday and Wednesday.

Blocking the emotions of old memories.

Dolan and collaborators do an interesting study showing that beta-adrenergic blockers (which are known to block the initial storage of emotions along with declarative memory of an event) can later also strip away the emotional memories associated with an event during its recall, an effect which persists for at least 24 hours in the absence of the blocker . The abstract:
Memory enhancement for emotional events is dependent on amygdala activation and noradrenergic modulation during learning. A potential role for noradrenaline (NE) during retrieval of emotional memory is less well understood. Here, we report that administration of the β-adrenergic receptor antagonist propranolol at retrieval abolishes a declarative memory enhancement for emotional items. Critically, this effect persists at a subsequent 24 h memory test, in the absence of propranolol. Thus, these findings extend our current understanding of the role of NE in emotional memory to encompass effects at retrieval, and provide face validity to clinical interventions using β-adrenergic antagonists in conjunction with reactivation of unwanted memories in anxiety-related disorders.

Thursday, April 01, 2010

Mate preferences predicted by national health.

DeBruine et al have done an interesting study in which 4500 women from 30 different countries in Europe and the Americas went to a Web site (faceresearch.org) and noted their preferences between pairs of 20 different white male faces, some of them digitally manipulated to increase or decrease masculine features. They wanted to test the evolutionary psychology suggestion that women may prefer tough-looking guys because their offspring are more likely to survive. (The downside is that manly men tend not to be the best dads, investing fewer resources in their offspring.) The less healthy a woman's country was, the more likely she was to prefer the masculinized faces. Those at the high end of the macho-preferring scale came from Brazil, also ranked as having the worst health. Those who tended more toward the girly men were from Belgium and Sweden, the healthiest. Here is their abstract:
Recent formulations of sexual selection theory emphasize how mate choice can be affected by environmental factors, such as predation risk and resource quality. Women vary greatly in the extent to which they prefer male masculinity and this variation is hypothesized to reflect differences in how women resolve the trade-off between the costs (e.g. low investment) and benefits (e.g. healthy offspring) associated with choosing a masculine partner. A strong prediction of this trade-off theory is that women's masculinity preferences will be stronger in cultures where poor health is particularly harmful to survival. We investigated the relationship between women's preferences for male facial masculinity and a health index derived from World Health Organization statistics for mortality rates, life expectancies and the impact of communicable disease. Across 30 countries, masculinity preference increased as health decreased. This relationship was independent of cross-cultural differences in wealth or women's mating strategies. These findings show non-arbitrary cross-cultural differences in facial attractiveness judgements and demonstrate the use of trade-off theory for investigating cross-cultural variation in women's mate preferences.

Facilitating choice with a electrical zap to the head

Hecht et al. show that a 2 milliamp direct current from a battery (small and safe, but noticeable to subjects) passed between one saline-soaked surface sponge electrode placed on the head over the left dorsolateral prefrontal cortex (anodal, positive) and another over the right dorsolateral prefrontal cortex (cathodal, negative) causes participants to become quicker in selecting the most frequent alternative in a probabilistic guessing task, suggesting a cognitive facilitation in reasoning and decision-making processes.  Here is their abstract:
In a random sequence of binary events where one alternative occurs more often than the other, humans tend to guess which of the two alternatives will occur next by trying to match the frequencies of previous occurrences. Based on split-brain and unilaterally damaged patients' performances, it has been proposed that the left hemisphere (LH) tends to match the frequencies, while the right hemisphere (RH) tends toward maximizing and always choosing the most frequent alternative. The current study used transcranial direct current stimulation (tDCS) to test this hemispheric asymmetry hypothesis by stimulating the dorsolateral prefrontal cortex of each hemisphere and simultaneously inhibiting the corresponding region in the homotopic hemisphere, while participants were engaged in a probabilistic guessing task. Results showed no difference in strategy between the three groups (RH anodal/LH cathodal, LH anodal/RH cathodal, no stimulation) as participants predominantly matched the frequencies of the two alternatives. However, when anodal tDCS was applied to the LH and cathodal tDCS applied to the RH, participants became quicker to select the most frequent alternative. This finding is in line with previous evidence on the involvement of the LH in probabilistic learning and reasoning and adds to a number of demonstrations of anodal tDCS leading to some behavioral enhancement or change in bias.

Wednesday, March 31, 2010

A Mozart adagio

Second movement of the sonata started in Monday's post. David Goldberger playing treble, I'm playing base.

Overcoming status quo bias in our brains

Yet another interesting bit of work involving Ray Dolan and his collaborators.  Here is the abstract and a summary figure:
Humans often accept the status quo when faced with conflicting choice alternatives. However, it is unknown how neural pathways connecting cognition with action modulate this status quo acceptance. Here we developed a visual detection task in which subjects tended to favor the default when making difficult, but not easy, decisions. This bias was suboptimal in that more errors were made when the default was accepted. A selective increase in subthalamic nucleus (STN) activity was found when the status quo was rejected in the face of heightened decision difficulty. Analysis of effective connectivity showed that inferior frontal cortex (rIFC), a region more active for difficult decisions, exerted an enhanced modulatory influence on the STN during switches away from the status quo. These data suggest that the neural circuits required to initiate controlled, nondefault actions are similar to those previously shown to mediate outright response suppression. We conclude that specific prefrontal-basal ganglia dynamics are involved in rejecting the default, a mechanism that may be important in a range of difficult choice scenarios.


Effects of decision difficulty and default rejection on connectivity. (A) Coronal sections are shown. Circled are the regions that were entered into a connectivity analysis. (B) Schematic showing the winning dynamic causal model and the pattern of significant connections. Default rejection (reject) was associated with increased influence of the rIFC on the STN. The authors observed correlation of activity in bilateral inferior frontal cortex (IFC) and bilateral medial frontal cortex (MFC)with increasing reaction time for rejecting default behavior. They saw additional main effects of decision difficulty in both MFC and IFC, in line with specific recruitment of these regions during situations requiring increased cognitive control.

Tuesday, March 30, 2010

Harris: science can point to 'what ought to be'

This TED talk by Sam Harris is worth watching.  He makes the point that the fact-value distinction is far from clear.

Sociopaths know right from wrong but don't care.

An interesting point from Cima et al. (open access):
Adult psychopaths have deficits in emotional processing and inhibitory control, engage in morally inappropriate behavior, and generally fail to distinguish moral from conventional violations. These observations, together with a dominant tradition in the discipline which sees emotional processes as causally necessary for moral judgment, have led to the conclusion that psychopaths lack an understanding of moral rights and wrongs. We test an alternative explanation: psychopaths have normal understanding of right and wrong, but abnormal regulation of morally appropriate behavior. We presented psychopaths with moral dilemmas, contrasting their judgments with age- and sex-matched (i) healthy subjects and (ii) non-psychopathic, delinquents. Subjects in each group judged cases of personal harms (i.e. requiring physical contact) as less permissible than impersonal harms, even though both types of harms led to utilitarian gains. Importantly, however, psychopaths’ pattern of judgments on different dilemmas was the same as those of the other subjects. These results force a rejection of the strong hypothesis that emotional processes are causally necessary for judgments of moral dilemmas, suggesting instead that psychopaths understand the distinction between right and wrong, but do not care about such knowledge, or the consequences that ensue from their morally inappropriate behavior.

Monday, March 29, 2010

Monday Mozart allegro

Monday, Wednesday, Friday this week I'm posting the three movements of the Mozart Sonata for 4-hands, K. 358. which I played in concert with David Goldberger in Fort Lauderdale on March 7. Today is the Allegro.

Babies are born to dance.

From Zentnera and Eerolab (open access):
Humans have a unique ability to coordinate their motor movements to an external auditory stimulus, as in music-induced foot tapping or dancing. This behavior currently engages the attention of scholars across a number of disciplines. However, very little is known about its earliest manifestations. The aim of the current research was to examine whether preverbal infants engage in rhythmic behavior to music. To this end, we carried out two experiments in which we tested 120 infants (aged 5–24 months). Infants were exposed to various excerpts of musical and rhythmic stimuli, including isochronous drumbeats. Control stimuli consisted of adult- and infant-directed speech. Infants’ rhythmic movements were assessed by multiple methods involving manual coding from video excerpts and innovative 3D motion-capture technology. The results show that (i) infants engage in significantly more rhythmic movement to music and other rhythmically regular sounds than to speech; (ii) infants exhibit tempo flexibility to some extent (e.g., faster auditory tempo is associated with faster movement tempo); and (iii) the degree of rhythmic coordination with music is positively related to displays of positive affect. The findings are suggestive of a predisposition for rhythmic movement in response to music and other metrically regular sounds.

Friday, March 26, 2010

The Schubert Fantasy - part 3

Following Monday's and Wednesday's postings, the final portion of the Schubert Fantasy. I'm playing treble, David Goldberger is playing base.

Wal-Mart Moral Lessons

John Tierney describes cross cultural studies of sharing and fairness (comparing, for example, hunter-gatherers with midwestern Wal-Mart shoppers) that found:
...the strongest predictor of fairness was the community’s level of “market integration,” - measured by the percentage of the diet that was purchased. The people who got all or most of their food by hunting, fishing, foraging or growing it themselves were less inclined to share a prize equally....Markets don’t work very efficiently if everyone acts selfishly and believes everyone else will do the same...You end up with high transaction costs because you have to have all these protections to cover every loophole. But if you develop norms to be fair and trusting with people beyond your social sphere, that provides enormous economic advantages and allows a society to grow.
The work he is summarizing is by Henrich et al. Their abstract:
Large-scale societies in which strangers regularly engage in mutually beneficial transactions are puzzling. The evolutionary mechanisms associated with kinship and reciprocity, which underpin much of primate sociality, do not readily extend to large unrelated groups. Theory suggests that the evolution of such societies may have required norms and institutions that sustain fairness in ephemeral exchanges. If that is true, then engagement in larger-scale institutions, such as markets and world religions, should be associated with greater fairness, and larger communities should punish unfairness more. Using three behavioral experiments administered across 15 diverse populations, we show that market integration (measured as the percentage of purchased calories) positively covaries with fairness while community size positively covaries with punishment. Participation in a world religion is associated with fairness, although not across all measures. These results suggest that modern prosociality is not solely the product of an innate psychology, but also reflects norms and institutions that have emerged over the course of human history.

Everybody have fun.

Elizabeth Kolbert writes a very accessible article (PDF here) having the title of this post in the March 22 issue of The New Yorker. The topic is happiness, how to measure it, and why we are so bad at knowing what will actually make us happy (the paradox of "the happy peasant and the miserable millionaire"). It covers the same territory as the Daniel Gilbert book "Stumbling on Happiness" that I abstracted in MindBlog several years ago (enter Gilbert in the search box in the left column to find those posts).

Thursday, March 25, 2010

Cooperative behavior cascades in human social networks

Fowler and Christakis, in an open access article in PNAS, demonstrate that one cooperative act has a multiplying effect. In an iterative game, when a subject gives money to help someone else, the recipients of that cash then became more likely to give their own money away in the next round. This leads to a cascade of generosity, in which the itch to cooperate spreads first to three people and then to the nine people that those three people interact with, and then to the remaining individuals in subsequent waves of the experiment. (Uncooperative behavior can spread and persist as well.)  Here is one of their figures. 



Figure - A hypothetical cascade. This diagram illustrates the difference between the spread of the interpersonal effects across individuals and the persistence of effects across time. We abstract from the numerous interactions that take place between individuals in these experiments to focus on a specific, illustrative set of pathways. Cooperative behavior spreads three degrees of separation: if Eleni increases her contribution to the public good, it benefits Lucas (one degree), who gives more when paired with Erika (two degrees) in period 2, who gives more when paired with Jay (three degrees) in period 3, who gives more when paired with Brecken in period 4. The effects also persist over time, so that Lucas gives more when paired with Erika (period 2) and also when paired with Lysander (period 3), Bemy (period 4), Sebastian (period 5), and Nicholas (period 6). There is also persistence at two degrees of separation, because Erika givesmore not only when paired with Jay (period 3) but also when paired with Harla (period 4) and James (period 5). All the paths in this illustrative cascade are supported by significant results in the experiments, and it is important to note that if Eleni decreases her initial contribution, her uncooperative behavior can spread and persist as well.