Thursday, May 27, 2010

Mindblog as dutiful tourist

I'm heading back to Wisconsin from Istanbul tomorrow, and have just taken time to post the obligatory vacation shots. Being a foodie, I've been especially attentive to treats of the sort shown below, a local cheap restaurant to which my student guide Fatih took us after my piano and lecture gig.

Monday, May 17, 2010

A lecture and piano recital in Istanbul

As this post appears I will just be landing in Istanbul to attend "Cognitive VII", an international cognitive neuroscience meeting being held here May 18-20. The organizers asked me to give both a piano recital and a talk at the May 19 session, which features several talks on art, music, and the brain. I've elected to play a number of pieces, most of which I have previously posted on YouTube. The Chopin Prelude Op. 28 no. 17 shown just below I posted this past weekend.

F. Chopin - Nocturne Op. 27 no. 2
F. Chopin - Prelude Op. 28, no. 17
E. Grieg - Lyric Pieces Op. 43, no. 5 Erotic Piece
E. Grieg - Lyric Pieces Op. 47, no. 5 Melancholy
E. Grieg - Lyric Pieces Op. 54, no. 4, Notturno
C. Debussy - Reverie  (version I  and version II)
C. Debussy - Minuette from Suite Bergmanesque
C. Debussy - Valse Romantique

The talk following this performance is titled "Who wants to know - the nature of our subjective I." I have posted a web version of this talk on my website.

I will be on vacation in Istanbul after the meeting, and probably will suspend MindBlog posts for several weeks.

Here is the Chopin prelude:

Friday, May 14, 2010

The chemistry of commitment

Parker-Pope does an interesting article on a topic that has repeatedly appeared in this blog, the role of vasopressin in regulating affiliative behavior. Here she notes studies on correlations between a gene regulating vasopressin activity and commitment and marital stability. Studies on 552 sets of twins found: who carried a variation in the gene were less likely to be married, and those who had wed were more likely to have had serious marital problems and unhappy wives. Among men who carried two copies of the gene variant, about a third had experienced a serious relationship crisis in the past year, double the number seen in the men who did not carry the variant.
Parker-Pope also notes experiments suggesting that women might have developed a kind of early warning system to alert them to relationship threats.

Thursday, May 13, 2010

More on the science of morality - baby morals.

Sam Harris deals with the massive (mostly critical) response to the TED lecture which I pointed to in my March 30 post, in which he argues for a natural and scientific basis for morality.  And,  Paul Bloom discusses observations on very young human infants that provide very strong evidence for our having an innate primitive moral capacity that is refined by individual and group interactions starting in the first year after birth .

Wednesday, May 12, 2010

Nasal attraction

Olsson and Laska find an exception to the generalization that women sense chemicals better than men. Men are better at detecting the lily-of-the-valley flower smell of the compound bourgeonal. This same compound is a powerful chemical attractant for male sperm cells. Because the olfactory receptors on sperm cells are also expressed in the human nose, and selective pressure for keener receptors would act on men but not on women, it makes sense that men are more sensitive to the sperm attractant.
Recent studies have shown that sperm chemotaxis critically involves the human olfactory receptor OR1D2, which is activated by the aromatic aldehyde bourgeonal. Given that both natural and sexual selection may act upon the expression of receptors, we hypothesized that human males are more sensitive than human females for bourgeonal. Using a 3-alternative forced-choice test procedure, olfactory detection thresholds were determined for a total of 500 subjects, 250 males, and 250 females between 18 and 40 years of age. We found that male subjects detected bourgeonal at significantly lower concentrations (mean value: 13 ppb) compared with female subjects (mean value: 26 ppb), whereas no such gender difference in olfactory sensitivity was found with helional, a structural analog of bourgeonal, and with n-pentyl acetate, an aliphatic ester, which were tested in parallel. Males and females did not differ in their frequency of specific anosmia for any of the 3 odorants. The frequency distributions of olfactory detection thresholds were monomodal with all 3 odorants in both genders. Olfactory detection thresholds did not differ significantly between pre- and postovulatory females with any of the 3 odorants. To the best of our knowledge, this is the first study ever to find a human male superiority in olfactory sensitivity. Single nucleotide polymorphisms and/or copy number variations in genes coding for olfactory receptors may be the proximate cause for our finding, whereas a gender difference in the behavioral relevance of bourgeonal may be the ultimate cause.

Tuesday, May 11, 2010

Eipgenetics and cognitive aging

Aging-related cognitive decline begins for most of us when we are in our late 40s.  Deterioration is mosty pronounced the ability to recall facts and experiences (declarative memory) and has been associated with aberrant changes in gene expression in the brain's hippocampus and frontal lobe. Peleg et al. now find support for an emerging hypothesis that changes in the epigenetic modification of chromatin in the adult central nervous system drive cognitive decline. They show that restoring a reaction that places acetyl groups on the histone proteins that regulate gene expression reinstates the expression of learning-induced genes.
As the human life span increases, the number of people suffering from cognitive decline is rising dramatically. The mechanisms underlying age-associated memory impairment are, however, not understood. Here we show that memory disturbances in the aging brain of the mouse are associated with altered hippocampal chromatin plasticity. During learning, aged mice display a specific deregulation of histone H4 lysine 12 (H4K12) acetylation and fail to initiate a hippocampal gene expression program associated with memory consolidation. Restoration of physiological H4K12 acetylation reinstates the expression of learning-induced genes and leads to the recovery of cognitive abilities. Our data suggest that deregulated H4K12 acetylation may represent an early biomarker of an impaired genome-environment interaction in the aging mouse brain.

Monday, May 10, 2010

More on creativity and the brain

This past Saturday's NYTimes had an article featuring work by Rex Jung which was the subject of last Tuesday's post. A bit facile and simplistic, but I thought I would pass on some of the eye-catching graphics supplied by researchers:

Images from brain research conducted by the Mind Research Network. While intelligence and skill are associated with the fast and efficient firing of neurons in the brain, subjects who tested high in creativity had thinner white matter and connecting axons that slow nerve traffic. In these images, the green tracks show the white matter being analyzed. The yellow and red spots show where creativity corresponds with slower nerve traffic. The blue areas show where “openness to experience,” associated with creativity, corresponds with slower nerve traffic. (from Jung).

Left, before an insight, activity drops in the visual cortex; right, in the “aha! moment,” activity in the right temporal lobe spikes. (from Ohn Kounios, Drexel University)

Friday, May 07, 2010

Chimps have tools for sex

Here is a great item from Tierney in this past Tuesday's NYTimes Science section. With the use of about 20 different tools having been documented in different groups of chimpanzees, now a 'come hither' tool for a male trying to get a female to mate has been recorded.
The male will pluck a leaf, or a set of leaves, and sit so the female can see him. He spreads his legs so the female sees the erection, and he tears the leaf bit by bit down the midvein of the leaf (making a rasping noise), dropping the pieces as he detaches them. Sometimes he’ll do half a dozen leaves until she notices.,,,And then?...Presumably she sees the erection and puts two and two together, and if she’s interested, she’ll typically approach and present her back side, and then they’ll mate. might see this chimp as the equivalent of a human (wearing pants, one hopes) trying to attract women by driving around with a car thumping out 120-decibel music... But it would be fairer to compare the clipped leaf with the most popular human sex tool...the vibrator, considered taboo a few decades ago, has become one of the most common household appliances in the United States....

Thursday, May 06, 2010

William's syndrome: Disappearance of racism along with social fear.

Meyer-Lindenberg and collaborators report the interesting observation that racial stereotyping, but not gender stereotyping, disappears in children with Williams syndrome (who lack social fear):
Stereotypes — often implicit attributions to an individual based on group membership categories such as race, religion, age, gender, or nationality — are ubiquitous in human interactions. Even three-year old children clearly prefer their own ethnic group and discriminate against individuals of different ethnicities. While stereotypes may enable rapid behavioural decisions with incomplete information, such biases can lead to conflicts and discrimination, especially because stereotypes can be implicit and automatic, making an understanding of the origin of stereotypes an important scientific and socio-political topic. An important process invoked by out-groups is social fear. A unique opportunity to study the contribution of this mechanism to stereotypes is afforded by individuals with the microdeletion disorder Williams syndrome (WS), in which social fear is absent, leading to an unusually friendly, high approachability behaviour, including towards strangers. Here we show that children with WS lack racial stereotyping, though they retain gender stereotyping, compared to matched typically developing children. Our data indicate that mechanisms for the emergence of gender versus racial bias are neurogenetically dissociable. Specifically, because WS is associated with reduced social fear, our data support a role of social fear processing in the emergence of racial, but not gender, stereotyping.

Wednesday, May 05, 2010

Our brain as a cognitive miser - where decision costs are registered.

McGuire1 and Botvinick show that lateral prefrontal cortex (LPFC) is where the costs of cognitively demanding decisions are reflected. From their introduction:
...decision-makers balance a motive to maximize gains with a motive to minimize decision costs. The concept of decision costs helps explain such behavioral phenomena as effort-accuracy tradeoffs, reliance on fast and frugal heuristics, failure to consider all available alternatives, effort discounting, the use of stereotypes, and salutary effects of monetary incentives. Amplified decision costs might play a role in clinical depression and chronic fatigue syndrome. This idea is related to the view that decision-making consumes a limited resource, and, more generally, that humans act as cognitive misers.
Their abstract: (Experiment 1 elicited repeated self-reports of experienced decision costs, measured in terms of participants’ rated desire to avoid the task. Experiment 2 sought to confirm the relevance of LPFC to the evaluation of decision costs, with costs measured directly in terms of observed avoidance behavior.)
Human choice behavior takes account of internal decision costs: people show a tendency to avoid making decisions in ways that are computationally demanding and subjectively effortful. Here, we investigate neural processes underlying the registration of decision costs. We report two functional MRI experiments that implicate lateral prefrontal cortex (LPFC) in this function. In Experiment 1, LPFC activity correlated positively with a self-report measure of costs as this measure varied over blocks of simple decisions. In Experiment 2, LPFC activity also correlated with individual differences in effort-based choice, taking on higher levels in subjects with a strong tendency to avoid cognitively demanding decisions. These relationships persisted even when effects of reaction time and error were partialled out, linking LPFC activity to subjectively experienced costs and not merely to response accuracy or time on task. In contrast to LPFC, dorsomedial frontal cortex—an area widely implicated in performance monitoring—showed no relationship to decision costs independent of overt performance. Previous work has implicated LPFC in executive control. Our results thus imply that costs may be registered based on the degree to which control mechanisms are recruited during decision-making.

Tuesday, May 04, 2010

Slowing down the brain may enhance creativity.

Geddes points to work by Jung et al. that suggest an inverse correlation in human subjects between brain connectivity, reflected by the amount of the cortical myelin that sheathes nerve tracts (see the illustrations here), and creativity, assayed by a "composite creativity index."  If  less myelin corresponds to slower communication between regions of the brain, this could suggest that slowing down our brains makes them more creative:
That creativity and psychopathology are somehow linked remains a popular but controversial idea in neuroscience research. Brain regions implicated in both psychosis-proneness and creative cognition include frontal projection zones and association fibers. In normal subjects, we have previously demonstrated that a composite measure of divergent thinking (DT) ability exhibited significant inverse relationships in frontal lobe areas with both cortical thickness and metabolite concentration of N-acetyl-aspartate (NAA). These findings support the idea that creativity may reside upon a continuum with psychopathology. Here we examine whether white matter integrity, assessed by Fractional Anisotropy (FA), is related to two measures of creativity (Divergent Thinking and Openness to Experience). Based on previous findings, we hypothesize inverse correlations within fronto-striatal circuits. Seventy-two healthy, young adult (18–29 years) subjects were scanned on a 3 Tesla scanner with Diffusion Tensor Imaging. DT measures were scored by four raters (α = .81) using the Consensual Assessment Technique, from which a composite creativity index (CCI) was derived. We found that the CCI was significantly inversely related to FA within the left inferior frontal white matter (t = 5.36, p = .01), and Openness was inversely related to FA within the right inferior frontal white matter (t = 4.61, p = .04). These findings demonstrate an apparent overlap in specific white matter architecture underlying the normal variance of divergent thinking, openness, and psychotic-spectrum traits, consistent with the idea of a continuum.

Monday, May 03, 2010

Emotions can persist longer than memory of their induction.

Feinstein et al. provide evidence that a feeling of emotion can endure beyond the conscious recollection for the events that initially triggered the emotion:
Can the experience of an emotion persist once the memory for what induced the emotion has been forgotten? We capitalized on a rare opportunity to study this question directly using a select group of patients with severe amnesia following circumscribed bilateral damage to the hippocampus. The amnesic patients underwent a sadness induction procedure (using affectively-laden film clips) to ascertain whether their experience of sadness would persist beyond their memory for the sadness-inducing films. The experiment showed that the patients continued to experience elevated levels of sadness well beyond the point in time at which they had lost factual memory for the film clips. A second experiment using a happiness induction procedure yielded similar results, suggesting that both positive and negative emotional experiences can persist independent of explicit memory for the inducing event. These findings provide direct evidence that a feeling of emotion can endure beyond the conscious recollection for the events that initially triggered the emotion.

Sunday, May 02, 2010

Embodyment: a two-minute powerful pose raises your testosterone levels

I pass on this fascinating item from a mindblog reader who has pointed out a number of other interesting articles to me. The article by Carnay, Cuddy, and Yap is titled "Power Posing: Brief Nonverbal Displays Affect Neuroendocrine Levels and Risk Tolerance."

Hey, I tried it, puffing up my chest and letting my shoulders rest back for two minutes left me feeling way more strong and assertive (now....where can I find a cheap saliva testosterone  home test kit...).

Here is the abstract:
Humans and other animals express power through open, expansive postures, and powerlessness through closed, constrictive postures. But can these postures actually cause power? As predicted, results revealed that posing in high-power (vs. low-power) nonverbal displays caused neuroendocrine and behavioral changes for both male and female participants: High-power posers experienced elevations in testosterone, decreases in cortisol, and increased feelings of power and tolerance for risk; low-power posers exhibited the opposite pattern. In short, posing in powerful displays caused advantaged and adaptive psychological, physiological, and behavioral changes — findings that suggest that embodiment extends beyond mere thinking and feeling, to physiology and subsequent behavioral choices. That a person can, via a simple two-minute pose, embody power and instantly become more powerful has real-world, actionable implications.
Click here for PDF of article to appear in Psychological Science