Thursday, July 31, 2008

Your genes and your politics.

Here are some clips from a piece by Constance Holden reporting on presentations at the recent annual Behavior Genetics Association meeting.

Numerous studies over the past 2 decades...have indicated that genes have a significant influence over whether you're "liberal" or "conservative" on various political and social issues. Some heritability estimates have been as high as 50%. That's roughly the heritability found for many personality traits such as "extraversion" or "agreeableness," and it implies that, in a given population, about half of the variation in a particular trait is attributable to genetic differences.

Now James Fowler, UCSD, and grad student Christopher Dawes say they've produced fresh evidence that DNA also has a hand in the intensity of someone's partisan attachment and even in whether someone bothers to vote...they did that by crunching data from twin registries and the government's long-running National Longitudinal Study of Adolescent Health (NLSAH)...they matched data on voting by 396 Los Angeles-area twins, including identical (who share 100% of their genes) and fraternal (who average 50% genetic overlap) twins, obtained from Los Angeles voter-turnout records. All twins were same-sex pairs to avoid confounding results with sex differences. The researchers corrected for environmental factors such as whether more of the identical than fraternal twins were living together, which might inflate their degree of similarity. They concluded that the correlation for voting was much higher between pairs of identical (.71) than fraternal (.50) twins. From this they estimated the heritability of voting behavior--that is, whether people eligible to vote actually do so--at 53%, suggesting that at least half the individual variation can be traced to genetic influences. They found an even higher heritability--72%--when they replicated the study with data on 806 twins from NLSAH, they reported in the May issue of the American Political Science Review.

Several groups are now trying to correlate personality data with DNA markers from studies such as NLSAH, which contains DNA as well as behavioral data from many subjects, in hope of identifying specific genes that feed into underlying traits, such as "desire for cooperation," that Fowler, for one, believes have been selected for throughout human evolution. Studies so far have focused on the same genes that are of interest in psychiatric genetics--in particular those involved with neurotransmitters such as dopamine and serotonin that are known to be important in regulating higher brain activities.
We are talking here about the fact that genetics are important, not really going after a complex behavior like political leanings at the molecular level. What is important is that:
social scientists are plunging into biological and evolutionary issues. At least some are starting to acknowledge that humans are genetically unique individuals and not just cloned pawns of their environment. And that suggests that prophets and pundits, however prescient, are probably never going to get much better at predictions than they are now.

A Twin Valley collage

A few pics I made last Saturday in the yard of our Twin Valley home in Middleton, WI (click to enlarge).

Wednesday, July 30, 2008

Moral Hypocrisy

John Tierney has a nice piece in the NYTimes on studies that probe moral flip-flops of the sort evidenced in the current presidential campaign. Does the hypocrite really believe in his heart what he is saying? Clips:

In voting against the Bush tax cut in 2001, Senator John McCain said he “cannot in good conscience support a tax cut in which so many of the benefits go to the most fortunate.” Today he campaigns in favor of extending that same tax cut beyond its expiration date...Senator Barack Obama last year called himself a “longtime advocate” of public financing of election campaigns. This month, he reiterated his “support” for such financing while becoming the first major party presidential nominee ever to reject it for his own campaign...Do you think either of these men is a hypocrite?

Moral hypocrisy allows us to gain the social benefits of appearing virtuous without incurring the personal costs of virtuous behavior. If you can deceive even yourself into believing that you’re acting for the common good, you’ll have more energy and confidence to further your own interests — and your self-halo can persuade others to help you along.

But as useful as hypocrisy can be, it’s apparently not quite as basic as the human instinct to do unto others as you would have them do unto you. Your mind can justify double standards, it seems, but in your heart you know you’re wrong.

The Curious Parallel of Language and Species Evolution

An article in PLoS Biology with the title of this post with worth a look. It describes recent work that has it origins in Charles Darwin's passage in The Descent of Man: “The formation of different languages and of distinct species, and the proofs that both have been developed through a gradual process, are curiously parallel.”

Tuesday, July 29, 2008

If I'm Not Hot, Are You Hot or Not?

Here is a quirky piece. Check out the website indicated...

Prior research has established that people's own physical attractiveness affects their selection of romantic partners. This article provides further support for this effect and also examines a different, yet related, question: When less attractive people accept less attractive dates, do they persuade themselves that the people they choose to date are more physically attractive than others perceive them to be? Our analysis of data from the popular Web site http://HOTorNOT.com suggests that this is not the case: Less attractive people do not delude themselves into thinking that their dates are more physically attractive than others perceive them to be. Furthermore, the results also show that males, compared with females, are less affected by their own attractiveness when choosing whom to date.

WikiPathways...

I spent much of my training and early research career trying to figure out chemical pathways in cells, specifically the pathways linking light to nerve signals in our eyes. I was thus struck by this article describing evolution in the process of how the biology research community maintains and updates knowledge about complex pathway systems. It discusses WikiPathways.

Nasty, brutish and short - a record lifespan

Just to show you the opposite end of the lifespan spectrum - perhaps an antidote to our obsessing over whether we might expand human lifespan from 85 to, say, 105 - here is a curious note from the July 3 Nature on the shortest known vertebrate lifespan: three months.

The Madagascan chameleon Furcifer labordi has an annual life cycle, and spends most of its short life in the egg...Kristopher Karsten of Oklahoma State University in Stillwater and his colleagues monitored individuals from the time of hatching until death during several cycles. They found that they hatch in November; grow at astonishing rates; reach maturity by January; battle fiercely over mates, breed and lay their eggs by February; and then promptly drop dead. For the next nine months, the entire species is represented by eggs...This is the shortest lifespan ever recorded for a four-legged vertebrate animal.

Monday, July 28, 2008

Brain correlates of insight - the Eureka! moment

Jonah Lehrer, in the July 28 issue of The New Yorker, offers an article titled "The Eureka Hunt." Here is the abstract and the PDF is here (thanks to mindblog reader Gregory for the link):

Why do good ideas come to us when they do? On August 5, 1949, a firefighter named Wag Dodge survived an out-of-control fire in the Mann Gulch River Valley, in Montana. In a moment of desperate insight, he devised an escape plan by igniting the ground in front of him and laying down on the smoldering embers, inhaling the thin layer of oxygen clinging to the ground. There is something inherently mysterious about moments of insight. Dodge couldn’t explain where his idea came from. Stories like Dodge’s share a few essential features, which psychologists and neuroscientists use to define “the insight experience.” Mark Jung-Beeman, a cognitive neuroscientist at Northwestern University, has spent the past fifteen years trying to figure out what happens inside the brain when people have an insight. Jung-Beeman became interested in the nature of insight in the early nineteen-nineties, while researching the right hemisphere of the brain. Mentions Jonathan Schooler. Jung-Beeman decided to compare word puzzles—or Compound Remote Associate Problems (C.R.A.)—solved in moments of insight with those solved by methodical testing. He teamed up with John Kounios, a psychologist at Drexler University, and they combined fMRI and EEG (electroencephalography) testing to scan people’s brains while they solved the puzzles. The resulting study, published in 2004, found that people who solved puzzles with insight activated a specific subset of cortical areas. Although the answer seemed to appear out of nowhere, the mind was carefully preparing itself for the breakthrough. The suddenness of the insight is preceded by a burst of brain activity. Thirty milliseconds before the answer appears, the EEG registers a spike of gamma rhythm. A small fold of tissue on the surface of the right hemisphere, the anterior superior temporal gyrus (aSTG), becomes unusually active in the second before the insight. Once the brain is sufficiently focused on the problem, the cortex needs to relax, to seek out the more remote association in the right hemisphere that will provide the insight. As Kounios sees it, the insight process is an act of cognitive deliberation transformed by accidental, serendipitous connections. Mentions Joydeep Bhattacharya and Henri Poincaré. The brain area responsible for recognizing insight is the prefrontal cortex. Earl Miller, a neuroscientist at M.I.T., spent five years studying the prefrontal cortex. He was eventually able to show that it wasn’t simply an aggregator of information, but rather it was more like a conductor, waving its baton and directing the players. In 2001, Miller and Princeton neuroscientist Jonathan Cohen published an influential paper laying out their theory of how the prefrontal cortex controls the rest of the brain. It remains unclear how simple cells recognize what the conscious mind cannot. An insight is just a fleeting glimpse of the brain’s huge store of unknown knowledge.

Mendelssohn, continued

Here is the weekly posting of an portion of the house concert at Twin Valley on 6/29/08 the Andante expressivo from Mendelssohn's 2nd piano trio.

Resveratrol, anti-aging, continued...

After getting a comment about the merits of different resveratrol sources from a blog reader in response post just below , I clicked around and found this link that leads on to an instructional video, discussion of preparations, price comparisons, etc. Numerous vendors for this stuff are appearing, like a cloud of snake-oil salesmen, and one I find particularly suspect is the slick Biotivia outfit, which doesn't even state the resveratrol content of their wondrous products.

Friday, July 25, 2008

Our relationship with mirrors...

Natalie Angier offers an excellent discussion of the biology, psychology and physics of our relationship with mirrors, how they are used in studies of self awareness in humans and animals, and also in treating disorders like phantom limb syndrome, chronic pain and post-stroke paralysis. I show here a nice graphic from the article explaining why few of us understand how our mirrors images really work.

Update on drugs that might increase lifespan

Nicholas Wade covers recent work by Sirtris, a startup company recently bought by GlaxoSmithKline for $720 million dollars. The drug candidates are activators of the enzyme sirtuin, involved in the 'famine reflex' that can switch body tissues to more efficient metabolism and increase life span in mice and other beasts (see graphic below). The commercially available form is resveratrol, obtained from skins of red grapes. It actually is a mixture of compounds having many actions other than sirtuin activation, some probably undesirable. (I actually ordered the stuff from a nutritional supplement supplier, and I'm playing with the idea of trying it, maybe following blood glucose levels.... the not so minor problem being the possibility that any positive physical, psychological, or chemical reactions to the stuff might be a placebo effect.)

Thursday, July 24, 2008

Psychopharma-parenting

I am usually relatively inattentive to other blogs in the "mind" area, because we tend to get into recycling each other's material, reminding me of what my grandmother told me once when I was 9 years old and we were driving through a small Texas town. I asked, "Grandmother, what do all these people do for a living?" The response was, "They take in each other's laundry."

In spite of my recycling sentiments, my thanks to MindHacks and Neuroanthropology (see blog list in right column) for pointing out this Colbert Report gem to me. (I can't understand how I missed it, the Colbert Show and the John Stewart Daily News are the only two television programs I religiously watch.)

Here is it, from two years ago on the culture that is drugging its kids:

Monoamine oxidase gene variant that correlates with aggression.

A colleague has pointed out a recent paper that compliments work mentioned in my May 14 post showing that brain monoamine oxidase activity (MAOA) levels predict male aggression. (MAOA inactivates the monoamine neurotransmitters norepinephrine, serotonin, and dopamine.) The paper by Guo et al. examines the effects of a particular genetic variant of the MAOA gene, a two-fold repeat of the 30-base pair promoter region VNTR. They correlated self-reported serious and violent delinquency and the 30-bp VNTR in the MAOA gene in a cohort of 2524 adolescents and young adults in the United States in the National Longitudinal Study of Adolescent Health. Here, for techie readers, is their abstract:

Genetic studies of delinquent and criminal behavior are rare in spite of the wide recognition that individuals may differ in their propensity for delinquency and criminality. Using 2524 participants in Add Health in the United States, the present study demonstrates a link between the rare 2 repeat of the 30-bp VNTR in the MAOA gene and much higher levels of self-reported serious and violent delinquency. The evidence is based on a statistical association analysis and a functional analysis of MAOA promoter activity using two human brain-derived cell lines: neuroblastoma SH-SY5Y and human glioblastoma 1242-MG. The association analysis shows that men with a 2R report a level of serious delinquency and violent delinquency in adolescence and young adulthood that were about twice (CI: (0.21, 3.24), P=0.025; and CI: (0.37, 2.5), P=0.008 for serious and violent delinquency, respectively) as high as those for participants with the other variants. The results for women are similar, but weaker. In the functional analysis, the 2 repeat exhibits much lower levels of promoter activity than the 3 or 4 repeat.

Wednesday, July 23, 2008

MindBlog's half-sour pickle recipe

This posting falls under the "random curious stuff" category mentioned in the title box of this blog. At the social/musical at my Twin Valley home on June 29, several people asked for the recipe for the half-sour pickles we had served with gazpacho as a garnish. Here it is, the result of several trials to get them the way I like them. Not guaranteed to please all....

Deric's final half sour pickle recipe:

-2 lbs pickling cucumbers
-1 bundle of dill heads and stalks
-Wash cukes and dill, cut dill stalks to ~2-3 inch lengths, cut ends off cukes, slice cukes lengthwise if they are large.
-layer dill and cukes in container (~2 quart jar or plastic container)
-pour in water to cover, then pour this water into quart (4 cup) measuring cup to determine its volume, i.e. the desired volume for the pickling mixture to be added (should be ~ 4 cups).
-add 1/4 cup sea or kosher or pickling salt to 2 cups water, dissolve
-add 1/3 cup rice wine vinegar (or other very mild vinegar), 1/2 teaspoon whole black peppercorns, 3-4 whole coriander seeds, 1/2 teaspoon mustard seeds, 4-6 cloves fresh garlic, finely chopped.
-add water to obtain the volume determined above (~4 cups) while mixing thoroughly and pour over pickles.
-rotate jar or container at intervals to mix thoroughly, leave two days at room temperature, until a few bubbles start to appear, then put in refrigerator.
-pickles should be ready to eat after ~ 4 days, flavor improves over two weeks.

Observing nerve cells rewire themselves after stroke damage.

In a technical tour de force, Winship and Murphy use the two photon imagining technique on living adult mouse brains to observe the individual neurons close to the site of damage caused by a stroke. In the first month — when paralysis is usually at its worst — they found that some neurons ditched their speciality for one particular limb and began processing information from multiple limbs. During the following month, as the affected brain region reorganized itself more permanently, those neurons re-specialized to a new single limb. Here is their abstract:

Functional mapping and microstimulation studies suggest that recovery after stroke damage can be attributed to surviving brain regions taking on the functional roles of lost tissues. Although this model is well supported by data, it is not clear how activity in single neurons is altered in relation to cortical functional maps. It is conceivable that individual surviving neurons could adopt new roles at the expense of their usual function. Alternatively, neurons that contribute to recovery may take on multiple functions and exhibit a wider repertoire of neuronal processing. In vivo two-photon calcium imaging was used in adult mice within reorganized forelimb and hindlimb somatosensory functional maps to determine how the response properties of individual neurons and glia were altered during recovery from ischemic damage over a period of 2–8 weeks. Single-cell calcium imaging revealed that the limb selectivity of individual neurons was altered during recovery from ischemia, such that neurons normally selective for a single contralateral limb processed information from multiple limbs. Altered limb selectivity was most prominent in border regions between stroke-altered forelimb and hindlimb macroscopic map representations, and peaked 1 month after the targeted insult. Two months after stroke, individual neurons near the center of reorganized functional areas became more selective for a preferred limb. These previously unreported forms of plasticity indicate that in adult animals, seemingly hardwired cortical neurons first adopt wider functional roles as they develop strategies to compensate for loss of specific sensory modalities after forms of brain damage such as stroke.

Tuesday, July 22, 2008

fMRI of perspective taking with robots!

Here is a quirky item... set up a human machine interaction, and as the machine is given more human-like response characteristics, parts of our brain that do 'theory of mind' (attributing intentions to others, etc.) become active. We humanize the robot. From the paper:

When our PC goes on strike again we tend to curse it as if it were a human being. Why and under which circumstances do we attribute human-like properties to machines? Although humans increasingly interact directly with machines it remains unclear whether humans implicitly attribute intentions to them and, if so, whether such interactions resemble human-human interactions on a neural level. In social cognitive neuroscience the ability to attribute intentions and desires to others is being referred to as having a Theory of Mind (ToM). With the present study we investigated whether an increase of human-likeness of interaction partners modulates the participants' ToM associated cortical activity.

...we investigated cortical activity modulation during highly interactive human-robot game. Increasing degrees of human-likeness for the game partner were introduced by means of a computer partner, a functional robot, an anthropomorphic robot and a human partner. The classical iterated prisoner's dilemma game was applied as experimental task which allowed for an implicit detection of ToM associated cortical activity...functional imaging data revealed a highly significant linear increase of cortical activity in the medial frontal cortex as well as in the right temporo-parietal junction in correspondence with the increase of human-likeness of the interaction partner...

Most popular consciousness papers

Most popular downloads for June 2008, from the ASSC archive. Also, some of the papers from the annual meeting in Taipei are here:

1. Destrebecqz, Arnaud and Peigneux, Philippe (2005) Methods for studying
unconscious learning. In: Progress in Brain Research. Elsevier, pp. 69-80.
2207 downloads from 27 countries. http://eprints.assc.caltech.edu/170/
2. Koriat, A. (2006) Metacognition and Consciousness. In: Cambridge handbook
of consciousness. Cambridge University Press, New York, USA. 1437 downloads
from 24 countries. http://eprints.assc.caltech.edu/175/
3. Dehaene, Stanislas and Changeux, Jean-Pierre and Naccache, Lionel and
Sackur, Jérôme and Sergent, Claire (2006) Conscious, preconscious, and
subliminal processing: a testable taxonomy. Trends in Cognitive Science, 10
(5). pp. 204-211. 1047 downloads from 25 countries.
http://eprints.assc.caltech.edu/20/
4. Mashour, George A. (2007) Inverse Zombies, Anesthesia Awareness, and the
Hard Problem of Unconsciousness. In: 11th Annual Meeting of the ASSC, Las
Vegas. 756 downloads from 17 countries. http://eprints.assc.caltech.edu/294/
5. Chalmers, David J. (2004) How can we construct a science of
consciousness? In: The Cognitive Neurosciences III. MIT Press, Cambridge,
MA. 714 downloads from 11 countries. http://eprints.assc.caltech.edu/28/

Monday, July 21, 2008

How we impose a natural order on events...

Goldin-Meadow et al. do interesting experiments on how speakers of different languages represent events nonverbally, finding that linguistic differences in subject-object-verb placement do not carry over into gestural depictions of the same event. (English, Chinese, and Spanish speakers typically use the order subject-verb-object to describe an event; Turkish speakers use subject-object-verb.) This suggests a natural cognitive sequence for representing events.

To test whether the language we speak influences our behavior even when we are not speaking, we asked speakers of four languages differing in their predominant word orders (English, Turkish, Spanish, and Chinese) to perform two nonverbal tasks: a communicative task (describing an event by using gesture without speech) and a noncommunicative task (reconstructing an event with pictures). We found that the word orders speakers used in their everyday speech did not influence their nonverbal behavior. Surprisingly, speakers of all four languages used the same order and on both nonverbal tasks. This order, actor–patient–act, is analogous to the subject–object–verb pattern found in many languages of the world and, importantly, in newly developing gestural languages. The findings provide evidence for a natural order that we impose on events when describing and reconstructing them nonverbally and exploit when constructing language anew.
The authors speculate:
...that, rather than being an outgrowth of communicative efficiency or the manual modality, actor-patient-act may reflect a natural sequencing for representing events. Entities are cognitively more basic and less relational than actions, which might lead participants to highlight entities involved in an action before focusing on the action itself, thus situating actor and patient before action. Moreover, there is a particularly close cognitive tie between objects and actions, which would link patient to action, resulting in an actor-patient-act order.

Mendelssohn, continued

The is the weekly posting of an portion of the house concert at Twin Valley on 6/29/08 the Molto allegro ed agitato from Mendelssohn's 1st piano trio.

Friday, July 18, 2008

The 'connectome' of our cerebral cortex

Hagmann et al. use diffusion mapping techniques to provide some awesome summary graphics of connectivity networks of our cerebral cortex. Regions of the neocortex are linked by a dense network of neural pathways, with several distinct nodes, like airline hubs. Their data:

...provides evidence for the existence of a structural core in human cerebral cortex. This complex of densely connected regions in posterior medial and parietal cortex is both spatially and topologically central within the brain. Its anatomical correspondence with regions of high metabolic activity and with some elements of the human default network suggests that the core may be an important structural basis for shaping large-scale brain dynamics. The availability of single-participant structural and functional connection maps now provides the opportunity to investigate interparticipant connectional variability and to relate it to differences in individual functional connectivity and behavior.

Click on figure to enlarge...

The Bio-Rad PCR song

Just to finish off our introduction to the brave new world of biotechnology advertising, here is the Bio-Rad PCR song. PCR, the polymerase chain reaction, is a laboratory technique used to amplify DNA that uses thermal cycling units made by Bio-Rad and others.

Thursday, July 17, 2008

Ubiquity of same-sex couplings in nature.

A student has pointed out to me an interesting article in Science American Mind on unorthodox sex in the animal kingdom:

As many as 1,500 species of wild and captive animals have been observed engaging in homosexual activity. Speculations seeking an evolutionary rationale are that animals may engage in same-sex couplings to diffuse social tensions, to better protect their young or to maintain fecundity when opposite-sex partners are unavailable—or simply because it is fun. Bisexuality is a natural state among animals, perhaps Homo sapiens included, despite the sexual-orientation boundaries most people take for granted. In humans the categories of gay and straight are socially constructed.

...homosexuality among some species, including penguins, appears to be far more common in captivity than in the wild. Captivity, scientists say, may bring out gay behaviors in part because of a scarcity of opposite-sex mates. In addition, an enclosed environment boosts an animal’s stress levels, leading to a greater urge to relieve the stress. Some of the same influences may encourage what some researchers call “situational homosexuality” in humans in same-sex settings such as prisons or sports teams.
Driscoll's article continues to describe a number of studies of same-sex partners in wild and captive animals.

Buy an automatic pipette from a boy band?

I am sitting now in my office in Bock Laboratories at the University of Wisconsin, where I ran a research factory for 30 years, generating Ph.D.s, Post-Docs, and some information on how our eyes turn light into a nerve signal. (My office as a retired professor is what I call a 'view with a room', and is actually upstairs at the top of the building in which my factory occupied half the third floor.) During that period I purchased hundreds of automatic pipettes (for accurately delivering small volumes of liquid) from the Eppendorf company, ordering from a simple dry brochure, and occasionally seeing an add in a scientific magazine.

Here, then, is my latest "Oh my Gawd, how things have changed" experience. Eppendorf using a Boy Band video to advertise its product:

Wednesday, July 16, 2008

The relaxation response correlates with changes in gene expression

Herbert Benson's book "The Relaxation Response" which appeared about 25 years ago, has had great influence in shaping public awareness of the debilitating effects of stress and anxiety and measure that can be taken to counter it. His institute at the Mass General Hospital has generated an interesting study of changes in gene expression profiles observed in short and long term relaxation response (RR) practitioners. A bit of context is provided in the introduction:

Mind-body approaches that elicit the RR include: various forms of meditation, repetitive prayer, yoga, tai chi, breathing exercises, progressive muscle relaxation, biofeedback, guided imagery and Qi Gong. One way that the RR can be elicited is when individuals repeat a word, sound, phrase, prayer or focus on their breathing with a disregard of intrusive everyday thoughts. The non-pharmacological benefit of the RR on stress reduction and other physiological as well as pathological parameters has attracted significant interest in recent years to decipher the physiological effects of the RR. In addition to decreased oxygen consumption, other consistent physiologic changes observed in long-term practitioners of RR techniques include decreased carbon dioxide elimination, reduced blood pressure, heart and respiration rate, prominent low frequency heart rate oscillations and alterations in cortical and subcortical brain regions.
The authors observed changes in gene expression profiles regulating molecular and biochemical pathways involved in cellular metabolism, oxidative phosphorylation, generation of reactive oxygen species and response to oxidative stress. They suggest that these changes to some degree serve to ameliorate the negative impact of stress (which is known to increase oxidative stress and promote a pro-inflammatory milieu).

Chopin's Heart

A quirky item that I pass on since I am a Chopin fanatic...From the "Random Samples" section of the 11 July issue of Science:

Frédéric Chopin died in France in 1849 at the age of 39 of what his death certificate recorded as "tuberculosis of the lungs and larynx." After his death, friends had the composer's heart removed, submerged in a jar of cognac, and placed in a Warsaw church in his native Poland in accordance with his wishes.

Now Polish scientists want to reopen the jar to see whether Chopin actually died of cystic fibrosis. Michal Witt of Warsaw's International Institute of Molecular and Cell Biology has argued that Chopin had childhood symptoms matching a mild form of the genetic illness, including respiratory infections, weakness, and delayed puberty. As an adult, Chopin was slight of stature, had a hard time climbing stairs, and occasionally had to be carried offstage after concerts. "If it turned out that Chopin had cystic fibrosis, this would be very special news for all those affected with CF," Witt says.

Witt hopes to persuade Polish authorities to open the niche where Chopin's heart is stored by 2010, the 200th anniversary of his birth. "It's a good moment to check, and once we have it in our hands it's a small matter to do a CT [computed tomography] scan and DNA test," says Tadeusz Dobosz, a geneticist at Wroc aw Medical University. Poland's Culture Ministry is considering the request.

Tuesday, July 15, 2008

Persistence of anxious temperament - brain correlates

The temperament we display in early childhood (introvesion versus extroversion, high versus low reactivity, anxiety in unfamiliar versus familiar situations, etc) is largely genetically determined and persists through life. The work of Kagan and others has shown that children classed as highly reactive as babies are more likely to be subdued in unfamiliar situations and report a dour mood and anxiety over the future. Anxious temperament is an early predictor of the later risk to develop anxiety, depression and drug abuse related to self-medicating. It becomes increasingly clear that people with anxious temperaments are come wired that way, telling them to calm down just doesn't work. Kalin and his colleagues here at Wisconsin have produced an interesting study on the relevant brain correlates of this behavior by looking at brain activity, anxious behavior and stress hormones in adolescent rhesus monkeys, which have been used in numerous studies as models to understand anxious temperament in human children. They found that individuals with the most anxious temperaments showed higher activity in the amygdala, which regulates emotion and triggers reactions to anxiety, such as the fight or flight response. These anxious monkeys had more metabolic activity in the amygdala in both secure and threatening situations. These differences remained over several years of testing. From their abstract:

Regardless of context, results demonstrated a trait-like pattern of brain activity (amygdala, bed nucleus of stria terminalis, hippocampus, and periaqueductal gray) that is predictive of individual phenotypic differences. Importantly, individuals with extreme anxious temperament also displayed increased activity of this circuit when assessed in the security of their home environment. These findings suggest that increased activity of this circuit early in life mediates the childhood temperamental risk to develop anxiety and depression. In addition, the findings provide an explanation for why individuals with anxious temperament have difficulty relaxing in environments that others perceive as non-stressful.

Self interest versus 'moral sentiment' in economic policy

A review by Bowles in Science considers:

...a shortcoming in the conventional economic approach to policy design: It overlooks the possibility that economic incentives that appeal to self interest may diminish ethical or other reasons for complying with social norms and contributing to the common good. It cites one simple example of this happening:

In Haifa, at six day care centers, a fine was imposed on parents who were late picking up their children at the end of the day. Parents responded to the fine by doubling the fraction of time they arrived late. When after 12 weeks the fine was revoked, their enhanced tardiness persisted unabated. While other interpretations are possible, the counterproductive imposition of the fines illustrate a kind of negative synergy between economic incentives and moral behavior. The fine seems to have undermined the parents' sense of ethical obligation to avoid inconveniencing the teachers and led them to think of lateness as just another commodity they could purchase.
A clip from the Bowles' discussion:
Although standard in economics, reliance solely on self-interest in the design of policies has never won universal assent. Until recently, however, dissenting views, like Titmuss' celebrated claim that paying for blood donations degrades the willingness to contribute, were thought to lack either empirical support or a coherent account of why separability might fail. But a recent experiment suggests that Titmuss may have been right, at least for women. Other experiments surveyed in this review provide additional evidence that material interests and moral sentiments are not separable in the sense required by the conventional economic approach to policy-making.

Economists, psychologists, and others, in part stimulated by these new empirical data, are well on their way to constructing an economic psychology of the interplay of self-regarding and other-regarding motivation that may eventually enlighten mechanism design and public policy....Good policies and constitutions are those that support socially valued ends not only by harnessing selfish preferences to public ends but also by evoking, cultivating, and empowering public-spirited motives. The modest tax on plastic grocery bags enacted in Ireland in 2002 that resulted in a 94 per cent decline in their use appears to have had just this effect : Carrying a plastic bag joined wearing a fur coat in the gallery of antisocial anachronisms.

Monday, July 14, 2008

Mendelssohn piano trios....

The is the first of what will be several weekly postings of portions of the house concert at Twin Valley on 6/29/08. This is the Andante con moto tranquillo from Mendelssohn's 1st piano trio. I am playingon the Steinway B, with Sonny Enslen (cello) and Daphne Tsao (violin).

The choices you make - indirect social influence.

I thought I was pass on this brief perspectives essay from Science by Jerker Denrell:

To what extent are the opinions you hold simply a reflection of the opinions of those you associate with? Most people like to think that their opinions are based on their own deliberations. Of course, there are exceptions. You may take into account the opinions of others if you believe they are better informed. You may even conform to the majority opinion in order to avoid being seen as deviant (1, 2). Studies of how norms and beliefs vary between groups, and how they are transmitted from peers or parents, testify to the importance of such social influence (3).

Explanations of social influence usually focus on why people are persuaded by or conform to the opinions of others (4). Although important, this research has neglected the role of information collection in belief formation and how biased beliefs, as well as social influence, can emerge from biased search processes (5).

For example, suppose you are deciding which of two cars to buy. If your neighbor buys one of the cars, you can observe it more closely and will thus learn more about its attributes. This opportunity to observe the car can bias your decision toward buying the same car, even if you do not care about whether you have the same car as your neighbor. This is especially true if acquiring information about cars other than your neighbor's is costly (6). If the information you learn about your neighbor's car is strongly positive, it makes sense to buy this car and discontinue the search. In this case you will not find out whether the other car is superior. If the information you learn is not very positive, however, it then makes sense to examine the other car. Only in this case will you find out how the two cars compare. Because the comparison process is asymmetric, you are overall more likely to buy the same car as your neighbor even if the information you learn is equally likely to be positive or negative.

The attitudes and behavior of others can also influence our learning processes by leading us to revisit objects and events that we had previously avoided because of poor past experiences (7). Suppose Bob likes a restaurant while Alice does not. By herself Alice might not visit the restaurant again, and her attitude would remain negative. But Alice might join Bob if he wants to go to the restaurant. By visiting the restaurant again, Alice gets a chance to change her opinion. Alice's attitude will depend on Bob's, but only because he influenced the probability of her revisiting the restaurant.

Finally, the number of your friends who engage in some activity can also influence your estimate of the value of this activity. If you have many friends who start firms, for example, your estimate of the chances of success will be based on a large sample size. A large sample size may lead you to have a higher estimate of the success rate than you would if the sample size were small. Experiments show that a large sample size leads to a more optimistic view when the outcome distribution is skewed (8). If only 10% succeed, you may only observe failures in a small sample, and will then underestimate the success rate.

These mechanisms produce behavior that looks like conformity: You are more likely to evaluate an activity positively if others do so. But in these examples your attitude is not directly influenced by hearing about the attitudes of others. Your attitude is only indirectly influenced by others because their behavior exposes you to additional samples of the activity.

Such indirect mechanisms of social influence are important, because even individuals who try to be impartial and make the best decision given the available information may fail to recognize that the available information is influenced by others (9). For example, a manager who tries to avoid discrimination may nevertheless come to believe that individuals who belong to the same social networks as the manager does are superior to those the manager seldom interacts with and has less information about. To learn more about these mechanisms, we need to broaden studies of social influence and belief formation to include the phases of learning and information collection that precede decision-making and judgment (10).

References and Notes

1. S. E. Asch, Sci. Am. 193, 31 (November, 1955).
2. M. Deutsch, H. Gerard, J. Abnorm. Soc. Psychol. 51, 629 (1955).
3. P. J. Richerson, R. Boyd, Not by Genes Alone: How Culture Transformed Human Evolution (Univ. of Chicago Press, Chicago, 2005).
4. R. B. Cialdini, N. J. Goldstein, Annu. Rev. Psychol. 55, 591 (2004).
5. Y. Trope, A. Liberman, in Social Psychology: Handbook of Basic Principles, E. T. Higgins, A. W. Kruglanski, Eds. (Guilford, New York, 1996), pp. 239-270.
6. N. V. Moshkin, R. Shachar, Market. Sci. 21, 435 (2002).
7. J. Denrell, G. Le Mens, Psychol. Rev. 114, 398 (2007).
8. R. Hertwig et al., Psychol. Sci. 15, 534 (2004).
9. J. Denrell, Psychol. Rev. 112, 951 (2005).
10. For recent research on the effect of sampling on judgment, see K. Fiedler, P. Juslin, Eds., Information Sampling and Adaptive Cognition (Cambridge Univ. Press, Cambridge, 2006).

Friday, July 11, 2008

Resveratrol - protection from ravages of aging.

In mice, at least....An article in Wired Magazine points to a multi-authored study in Cell Metabolism:

A small molecule that safely mimics the ability of dietary restriction (DR) to delay age-related diseases in laboratory animals is greatly sought after. We and others have shown that resveratrol mimics effects of DR in lower organisms. In mice, we find that resveratrol induces gene expression patterns in multiple tissues that parallel those induced by DR and every-other-day feeding. Moreover, resveratrol-fed elderly mice show a marked reduction in signs of aging, including reduced albuminuria, decreased inflammation, and apoptosis in the vascular endothelium, increased aortic elasticity, greater motor coordination, reduced cataract formation, and preserved bone mineral density. However, mice fed a standard diet did not live longer when treated with resveratrol beginning at 12 months of age. Our findings indicate that resveratrol treatment has a range of beneficial effects in mice but does not increase the longevity of ad libitum-fed animals when started midlife.

Where Ritalin acts in the brain to focus attention.

An interesting piece of work from Berridge's lab here at the University of Wisconsin shows that the cognition and attention enhancing drug Ritalin (methylphenidate, MPH) fine-tunes the functioning of neurons in the prefrontal cortex (PFC), which is involved in attention, decision-making and impulse control. While it enhances the efflux of the neurotransmitters norepinephrine and dopamine in PFC, it appears to have minimal effects elsewhere.

Only working memory–enhancing doses of MPH increased the responsivity of individual PFC neurons and altered neuronal ensemble responses within the PFC. The effects were not observed outside the PFC (i.e., within somatosensory cortex). In contrast, high-dose MPH profoundly suppressed evoked discharge of PFC neurons. These observations suggest that preferential enhancement of signal processing within the PFC, including alterations in the discharge properties of individual PFC neurons and PFC neuronal ensembles, underlie the behavioral/cognitive actions of low-dose psychostimulants.

Thursday, July 10, 2008

As new kind of science, as data deluge makes the scientific method obsolete...

An article by Chris Anderson in Wired Magazine, pointed out to me by my son Jon, argues that science as we have known it has ended. The argument is that the quest for knowledge that used to begin with grand theories now, in the petabyte age, begins with massive amounts of data. Google has set the new model for science. I show some clips here, and then follow with the contra argument by John Timmers that follows):

Google conquered the advertising world with nothing more than applied mathematics. It didn't pretend to know anything about the culture and conventions of advertising — it just assumed that better data, with better analytical tools, would win the day. And Google was right...Google's founding philosophy is that we don't know why this page is better than that one: If the statistics of incoming links say it is, that's good enough. No semantic or causal analysis is required. That's why Google can translate languages without actually "knowing" them (given equal corpus data, Google can translate Klingon into Farsi as easily as it can translate French into German). And why it can match ads to content without any knowledge or assumptions about the ads or the content.

The hypothesize-model-test model of science is becoming obsolete...The models we were taught in school about "dominant" and "recessive" genes steering a strictly Mendelian process have turned out to be an even greater simplification of reality than Newton's laws. The discovery of gene-protein interactions and other aspects of epigenetics has challenged the view of DNA as destiny and even introduced evidence that environment can influence inheritable traits, something once considered a genetic impossibility...the more we learn about biology, the further we find ourselves from a model that can explain it...There is now a better way. Petabytes allow us to say: "Correlation is enough." We can stop looking for models. We can analyze the data without hypotheses about what it might show. We can throw the numbers into the biggest computing clusters the world has ever seen and let statistical algorithms find patterns where science cannot.

The best practical example of this is the shotgun gene sequencing by J. Craig Venter. Enabled by high-speed sequencers and supercomputers that statistically analyze the data they produce, Venter went from sequencing individual organisms to sequencing entire ecosystems. In 2003, he started sequencing much of the ocean, retracing the voyage of Captain Cook. And in 2005 he started sequencing the air. In the process, he discovered thousands of previously unknown species of bacteria and other life-forms.

Venter can make some guesses about the animals — that they convert sunlight into energy in a particular way, or that they descended from a common ancestor. But besides that, he has no better model of this species than Google has of your MySpace page. It's just data. By analyzing it with Google-quality computing resources, though, Venter has advanced biology more than anyone else of his generation.

This kind of thinking is poised to go mainstream. In February, the National Science Foundation announced the Cluster Exploratory, a program that funds research designed to run on a large-scale distributed computing platform developed by Google and IBM in conjunction with six pilot universities. The cluster will consist of 1,600 processors, several terabytes of memory, and hundreds of terabytes of storage, along with the software, including Google File System, IBM's Tivoli, and an open source version of Google's MapReduce. Early CluE projects will include simulations of the brain and the nervous system and other biological research that lies somewhere between wetware and software.
Here is the immediate rejoinder to this article from John Timmers at Ars Technica.
Every so often, someone (generally not a practicing scientist) suggests that it's time to replace science with something better. The desire often seems to be a product of either an exaggerated sense of the potential of new approaches, or a lack of understanding of what's actually going on in the world of science. This week's version, which comes courtesy of Chris Anderson, the Editor-in-Chief of Wired, manages to combine both of these features in suggesting that the advent of a cloud of scientific data may free us from the need to use the standard scientific method.

It's easy to see what has Anderson enthused. Modern scientific data sets are increasingly large, comprehensive, and electronic. Things like genome sequences tell us all there is to know about the DNA present in an organism's cells, while DNA chip experiments can determine every gene that's expressed by that cell. That data's also publicly available—out in the cloud, in the current parlance—and it's being mined successfully. That mining extends beyond traditional biological data, too, as projects like WikiProteins are also drawing on text-mining of the electronic scientific literature to suggest connections among biological activities.

There is a lot to like about these trends, and little reason not to be enthused about them. They hold the potential to suggest new avenues of research that scientists wouldn't have identified based on their own analysis of the data. But Anderson appears to take the position that the new research part of the equation has become superfluous; simply having a good algorithm that recognizes the correlation is enough.

The source of this flight of fancy was apparently a quote by Google's research director, who repurposed a cliché that most scientists are aware of: "All models are wrong, and increasingly you can succeed without them." And Google clearly has. It doesn't need to develop a theory as to why a given pattern of links can serve as an indication of valuable information; all it needs to know is that an algorithm that recognizes specific link patterns satisfies its users. Anderson's argument distills down to the suggestion that science can operate on the same level—mechanisms, models, and theories are all dispensable as long as something can pick the correlations out of masses of data.

Science 2.0 I can't possibly imagine how he comes to that conclusion. Correlations are a way of catching a scientist's attention, but the models and mechanisms that explain them are how we make the predictions that not only advance science, but generate practical applications. One only needs to look at a promising field that lacks a strong theoretical foundation—high-temperature superconductivity springs to mind—to see how badly the lack of a theory can impact progress. Put in more practical terms, would Anderson be willing to help test a drug that was based on a poorly understood correlation pulled out of a datamine? These days, we like our drugs to have known targets and mechanisms of action and, to get there, we need standard science.

Anderson does provide two examples that he feels support his position, but they actually appear to undercut it. He notes that we know quantum mechanics is wrong on some level, but have been unable to craft a replacement theory after decades of work. But he neglects to mention two key things: without the testable predictions made by the theory, we'll never be able to tell how precisely it is wrong and, in those decades where we've failed to find a replacement, the predictions of quantum mechanics have been used to create the modern electronics industry, with the data cloud being a consequence of that.

If anything, his second example is worse. We can now perform large-scale genetic surveys of the life present in remote environments, such as the far reaches of the Pacific. Doing so has informed us that there's a lot of unexplored biodiversity on the bacterial level; fragments of sequence hint at organisms we've never encountered under a microscope. But as Anderson himself notes, the only thing we can do is make a few guesses as to the properties of the organisms based on who their relatives are, an activity that actually requires a working scientific theory, namely evolution. To do more than that, we need to deploy models of metabolism and ecology against the bacteria themselves.

Overall, the foundation of the argument for a replacement for science is correct: the data cloud is changing science, and leaving us in many cases with a Google-level understanding of the connections between things. Where Anderson stumbles is in his conclusions about what this means for science. The fact is that we couldn't have even reached this Google-level understanding without the models and mechanisms that he suggests are doomed to irrelevance. But, more importantly, nobody, including Anderson himself if he had thought about it, should be happy with stopping at this level of understanding of the natural world.

Meditation and executive function - untraining the brain.

A MindBlog reader passes on this link to a reposting of a interesting article by Chris Chatham on how easily normal conflicts in making decisions can be lessened by changes in attention. My May 1 post references other work on this topic.

Wednesday, July 09, 2008

Worried sick...achieving wellness?

I always enjoy it when a good curmudgeonly antidote comes along to temper bright eyed optimism. Such a contrast is provided by Zuger's review of very different books by Snyderman and Hadler. Synderman:

With chirpy, can-do optimism...recapitulates the standard wisdom. Watch your diet, exercise, lose weight, stop smoking, be screened regularly for a variety of dire illnesses, rein in cholesterol and blood sugar, stay in touch with your doctor and be sure to check out those aches and pains pronto, just in case. So speaks the medical establishment.
While Hadler:
..who is a longtime debunker of much the establishment holds dear...reminds us...we are all going to die...holding every dire illness at bay forever is simply not an option. The real goal is to reach a venerable age — say 85 — more or less intact. And the statistics tell Dr. Hadler that ignoring most of the advice Dr. Snyderman offers is the way to do it.
An excerpt from Hadler's book:
Daily, we are offered the image of the baby-boom generation going on forever, making impossible demands on successive generations to provide pensions, health care, and community. That, too, is fatuous. However, more of us are living longer than did our parents. Clearly, the likelihood that we will enjoy life as an octogenarian has increased over the course of the twentieth century. Far less clear is whether the likelihood of becoming a nonagenarian has increased similarly. It has certainly not done so at anything like the same rate as the likelihood of being an octogenarian. The effect is so striking that it has caused many of us to wonder if there is not a fixed longevity for our species, set around eighty-five years of age. Some have likened this to a warranty: you are off warranty at eighty-five, beyond is a bonus, and well beyond is a statistical oddity. This projected demographic is consistent with current population trends. With one caveat, these hard facts seem unlikely to change. It is possible that molecular biology can alter the fixed longevity of our species. But don't hold your breath. None of us will live to see that — and maybe no one ever will.

Eighty-five (+/- a little bit) appears to be the programmed life expectancy for our species. I grant that the science is imperfect. But eighty-five is a linchpin of my personal philosophy of life. I, for one, do not care how many diseases I harbor on my eighty-fifth birthday, though I prefer not to know that they are creeping up on me. I, for one, do not care which of these diseases carries me off as long as the leaving is gentle and the legacy meaningful. Perhaps the best we can reasonably hope for is eighty-five years of life free of morbidities that overwhelm our wherewithal to cope, then to die in our sleep on our eighty-fifth birthday.

Ecocultural basis of cognition

Farmers and fishermen are more holistic than herders. Uskul et al. offer a fascinating study on factors influencing holistic versus more focused perception:

It has been proposed that social interdependence fosters holistic cognition, that is, a tendency to attend to the broad perceptual and cognitive field, rather than to a focal object and its properties, and a tendency to reason in terms of relationships and similarities, rather than rules and categories. This hypothesis has been supported mostly by demonstrations showing that East Asians, who are relatively interdependent, reason and perceive in a more holistic fashion than do Westerners. We examined holistic cognitive tendencies in attention, categorization, and reasoning in three types of communities that belong to the same national, geographic, ethnic, and linguistic regions and yet vary in their degree of social interdependence: farming, fishing, and herding communities in Turkey's eastern Black Sea region. As predicted, members of farming and fishing communities, which emphasize harmonious social interdependence, exhibited greater holistic tendencies than members of herding communities, which emphasize individual decision making and foster social independence. Our findings have implications for how ecocultural factors may have lasting consequences on important aspects of cognition.

Tuesday, July 08, 2008

Brain regions active during different economic decisions.

The editor's choice section of science magazine spotlights an interesting paper in J. Neurosci:

When we make economic decisions, for example the purchase of a good or a service, our brain has to perform at least three computations. First, it has to assess the goal value of the good: in economic terms, our maximal willingness to pay. Second, it has to assess the decision value of the good: the goal value minus the unavoidable costs. Third, there is a prediction error, which indicates the deviation from one's expectations of reward; the prediction error is positive when something better than expected happens and negative when the opposite occurs. Unfortunately, these three related quantities are intermingled and are often highly correlated, making it challenging to isolate the neural regions performing these computations.

Hare et al. have attempted to measure goal value, decision value, and prediction error in a single neuroimaging task so that they could dissociate these parameters. They found that ventral striatum activation reflected prediction error and not goal or decision value. However, activity in the medial orbitofrontal cortex and the central orbitofrontal cortex correlated with goal value and decision value, respectively.
Here is a summary figure from the paper:

Figure - Combined activation maps for goal values (GVs), decision values (DVs), and prediction errors (PEs). Activity correlated with GVs in the mOFC is shown in red, activity correlated with DVs in the cOFC is shown in yellow, and activity correlated with PEs in the ventral striatum is shown in green.

Another Happiness Survey

The Univ. of Michigan press release describing work from the World Values Survey based at the University of Michigan Institute for Social Research. Denmark is the happiest nation in the world and Zimbabwe the unhappiest. The United States ranks 16th on the list, immediately after New Zealand.

Monday, July 07, 2008

Piazolla - Otono Portena

Here is the second Piazolla tango we did at the 6/29/08 Sunday musical at Twin Valley.

Brain Foods...

Gómez-Pinilla contributes a review article to the latest issue of Nature Reviews Neuroscience on how various dietary factors, in addition to some gut and brain hormones, increase the resistance of neurons to insults and promote mental fitness. I pass on one figure dealing with dietary omega-3 fatty acids, followed by a summary table.



The omega-3 fatty acid docosahexaenoic acid (DHA), which humans mostly attain from dietary fish, can affect synaptic function and cognitive abilities by providing plasma membrane fluidity at synaptic regions. DHA constitutes more than 30% of the total phospholipid composition of plasma membranes in the brain, and thus it is crucial for maintaining membrane integrity and, consequently, neuronal excitability and synaptic function. Dietary DHA is indispensable for maintaining membrane ionic permeability and the function of transmembrane receptors that support synaptic transmission and cognitive abilities. Omega-3 fatty acids also activate energy-generating metabolic pathways that subsequently affect molecules such as brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF1). IGF1 can be produced in the liver and in skeletal muscle, as well as in the brain, and so it can convey peripheral messages to the brain in the context of diet and exercise. BDNF and IGF1 acting at presynaptic and postsynaptic receptors can activate signalling systems, such as the mitogen-activated protein kinase (MAPK) and calcium/calmodulin-dependent protein kinase II (CaMKII) systems, which facilitate synaptic transmission and support long-term potentiation that is associated with learning and memory.


(Click to enlarge table.)

Friday, July 04, 2008

MRI of mental time travel.

Arzy et al. make the interesting observation that one's imagined self location influences the neural activity related to mental time travel. Slightly edited clips from the article:

A fundamental characteristic of human conscious experience is the ability to not only experience the present moment but also to recall the past and predict the future, or to "travel" back and forth in time, a facility that is called "mental time travel" (MTT)...Converging evidence from recent memory research suggests that re-experiencing and pre-experiencing an event rely on similar neural mechanisms. Similar strategies and the same brain regions are found to be used in imagining past and future events, as future predictions may be based on past memories... when changing the location of one's self in time to past or future, one does not only recall and predict, but one also changes one's mental egocentric perspective on life events. Moreover, from these new self-locations in time, other life events might be regarded differently with respect to their relations to past or future. Thus, when imagining oneself as 10 years younger, last year's events are in the future (relative future) in relation to the initially imagined self-location in time, and vice versa (relative past).
Since earlier studies had shown behavioral and electrophysiological differences between judgments about one's own body while taken from one's actual spatial self-location versus different imagined self-locations, and given evidence that shared mechanisms process time and space in the brain, the authors developed a behavioral paradigm to determine if differences are found not only between different self-locations in time (past, now, and future), but also while imagining events in the relative past or the relative future. They followed neural correlates of MTT using behavioral measures, evoked potential (EP) mapping, and electrical neuroimaging in healthy adult participants.


Stimuli and procedure. The three different self-locations in time (past, now, and future) are shown. Participants were asked to mentally imagine themselves in one of these self-locations, and from these self-locations to judge whether different self or nonself events (e.g., top row) already happened (relative past, darker colors) or are yet to happen (relative future, lighter colors).
Their work confirmed that:
...that MTT is composed of two different cognitive processes: absolute MTT, which is the location of the self to different points in time (past, present, or future), and relative MTT, which is the location of one's self with respect to the experienced event (relative past and relative future). These processes recruit a network of brain areas in distinct time periods including the occipitotemporal, temporoparietal, and anteromedial temporal cortices. Our findings suggest that in addition to autobiographical memory processes, the cognitive mechanisms of MTT also involve mental imagery and self-location, and that relative MTT, but not absolute MTT, is more strongly directed to future prediction than to past recollection.

Generators of MTT map are localized to the right temporoparietal, occipitotemporal, and left anteromedial temporal cortices.

When your brain Lies to You

Even when a lie is presented with a disclaimer, people often later remember it as true. A brief review in the OpEd section of the NYTimes shows how a well documented feature of our memory, source amnesia, might lead 10 % of us to thinking that Barack Obama is a Muslim.

Thursday, July 03, 2008

Brain markers that predict vulnerability to psychosis.

Honey et al. offer an interesting study in the Journal for Neuroscience. As indicated in these slightly edited clips from text and abstract:

They used a drug model of psychosis to relate presymptomatic physiology to symptom outcome. Ketamine induces transient psychotic symptoms in healthy volunteers and exacerbates existing symptoms in patients. They assessed brain responses, separately under placebo and ketamine treatments, in healthy volunteers across four cognitive challenges, each theoretically related to a symptom of psychosis. Two of the tasks (verbal working memory and attention) are associated with negative symptoms, which may result from social and cognitive disengagement attributable to reduced processing capacity of prefrontal cortex, leading to difficulties in concentration and maintaining task set. They predicted that prefrontal activity during the attention and working memory tasks would be associated with vulnerability to negative symptoms under ketamine.

A failure to monitor "inner speech" may provide a mechanism leading to auditory hallucinations, whereby self-generated speech is misattributed externally. Comparing verbal self-monitoring (imagining speech spoken by another person) with inner speech (minimal self-monitoring) increases prefrontal and temporal cortex activation in patients with auditory hallucinations. Ketamine produces auditory illusory experiences similar to the heightened auditory and visual awareness described by patients during the prodromal phase, and it has been suggested that these contribute to the development of hallucinations. The authors predicted that prefrontal and temporal cortex activation during a self-monitoring task would be associated with vulnerability to the auditory illusory experiences under ketamine.

Finally, a sentence completion task was used to engage brain regions associated with semantic processing. Thought disorder involves difficulty in constraining semantic threads of language, making speech disjointed and chaotic, as also observed under ketamine. In patients, the requirement to generate an appropriate semantic response to complete a sentence is associated with increased activation of left frontal and temporal cortex. They predicted that frontotemporal responses to a sentence completion task would predict vulnerability to thought disorder induced by ketamine.

They in fact found that brain responses to cognitive task demands under placebo predict the expression of psychotic phenomena after drug administration. Frontothalamic responses to a working memory task were associated with the tendency of subjects to experience negative symptoms under ketamine. Bilateral frontal responses to an attention task were also predictive of negative symptoms. Frontotemporal activations during language processing tasks were predictive of thought disorder and auditory illusory experiences. A subpsychotic dose of ketamine administered during a second scanning session resulted in increased basal ganglia and thalamic activation during the working memory task, paralleling previous reports in patients with schizophrenia. These results demonstrate precise and predictive brain markers for individual profiles of vulnerability to drug-induced psychosis.

Bias at the ballot box.

Berger et al. provide an interesting demonstration of how susceptible a voter's choice is to environmental cues. The two types of study done are described in Tim Lincoln's review of this work in Nature:

The first was an analysis of results from a general election held in Arizona in 2000, the ballot for which included a proposition to raise state sales tax from 5.0% to 5.6%, to increase education spending. Polling stations included churches, schools, community centres and government buildings.

Berger et al. predicted that voting in a school would produce more support for the proposition than voting in other places. Indeed it did, but not by much compared with other documented effects on voter choice such as order on the ballot paper. Nonetheless, the effect persisted through tests for various other confounding factors (for example, the possibility of a consistently different level of voter turnout at school polling locations).

The second study was a carefully run online experiment that also involved a proposed tax increase to fund schools. The 'voting environment' was manipulated by exposing participants to typical images of schools or control images. The upshot was the same, with the school images prompting greater (and apparently unconscious) support for the initiative than, for example, an image of an office.

All in all, the authors conclude that what they call contextual priming of polling location affects how people vote. They reasonably wonder whether such factors could, for example, influence voting in a church on such matters as gay marriage and stem-cell research.

But here's a thought. In the event of science spending being on the political agenda, why not offer the lab as a polling station? But maybe dim that fluorescent lighting, and persuade all those bearded fellows in white coats to take the day off — or not, as the case may be.

Wednesday, July 02, 2008

A Piazolla Tango

I'm working up the videos of the Sunday musical at Twin Valley mentioned in Monday's post. Here is Anton Piazolla's Invierno Porteno.

Why are musical chords cheerful or melancholy?

In the current issue of American Scientist, Cook and Hayashi offer a fascinating article on the psychoacoustics of harmony perception (PDF here). Major and minor chords entered Western music during the Renaissance, when two-part harmonies were supplanted by three-tone chords. The authors argue that human responses to these chords have a biological basis, rather than being learned (the opinion of most musical theorists). Their acoustical model explains harmony in terms of the relative positions of the three notes in a triad and how their complex higher harmonics, or upper partials, interact with them. Those of you interested in science and music should check out the special Nature series of essays on this topic.


Jean-Philippe Rameau, a French composer and author, wrote his Treatise on Harmony in 1722, one of the first and most influential studies of harmony in Western music. His book noted the profound emotional difference between major and minor chords: “The major mode is suitable for songs of mirth and rejoicing,” he wrote, while the minor mode was suitable for “plaints, and mournful songs.”

From their conclusions, after the analysis section of the paper:
Now that we have a model of how listeners identify a chord as major or minor, we may take the final step and speculate as to why the acoustical valence carries an emotional valence as well. We contend that the emotional symbolism of major and minor chords has a biological basis. Across the animal kingdom, vocalizations with a descending pitch are used to signal social strength, aggression or dominance. Similarly, vocalizations with a rising pitch connote social weakness, defeat or submission. Of course, animals convey these messages in other ways as well, with facial expressions, body posture and so on—but all else being equal, changes in the fundamental frequency of the voice have intrinsic meaning.

This same frequency code has been absorbed, though attenuated, in human speech patterns: A rising inflection is commonly used to denote questions, politeness or deference, whereas a falling inflection signals commands, statements or dominance. How might this translate to a musical context? If we start with a tense, ambiguous chord—for example, the augmented chord containing two 4-semitone intervals— and decrease any one of the three fundamentals by one semitone, the chord will resolve into a major key. It will then have a 5–4, 3–5, or 4–3 semitone structure. Conversely, if we resolve the ambiguous chord by raising any one of the three fundamentals by a semitone, we will obtain a minor chord. The universal emotional response to these chords stems, we believe, directly from an instinctive, preverbal understanding of the frequency code in nature. One of us (Cook) has explored this in more detail (see the bibliography).

Individual tastes and musical styles vary widely. In the West, music has changed over the centuries from styles that employed predominantly the resolved major and minor chords to styles that include more and more dissonant intervals and unresolved chords. Inevitably, some composers have taken this historical trend to its logical extreme, and produced music that fanatically avoids all indications of consonance or harmonic resolution. Such surprisingly colorless “chromatic” music is intellectually interesting, but notably lacking in the ebb and flow of tension and resolution that most popular music employs, and that most listeners crave. Whatever one’s own personal preferences may be for dissonance and unresolved harmonies, some kind of balance between consonance and dissonance, and between harmonic tension and resolution, seems to be essential—genre by genre, and individual by individual—to assure the emotional ups and downs that make music satisfying.

Making Memories, Again

Lasry et al. , in a letter to Science, offer an interesting interpretation of work reported in a previous post, showing that testing of already learned words enhances long-term recall when assessed 1 week later, whereas repeated studying had no beneficial effects. Here are their comments:

In their Report, "The critical importance of retrieval for learning" (15 February, p. 966), J. D. Karpicke and H. L. Roediger III show that delayed recall is optimized, not with repeated studying sessions, but with repeated testing sessions. The authors conclude that "retrieval during tests produces more learning than additional encoding."

We suggest a complementary interpretation. Classically, encoded information becomes consolidated and can later be retrieved. The tacit assumption is that retrieval of a consolidated memory is a read-only mechanism, which does not affect the memory. Recent studies have shown that elicited memories are in fact labile and become reconsolidated following each retrieval. Labile elicited memories require de novo protein synthesis to be maintained, similar to that of newly acquired memories. Neurobiological differences between consolidation and reconsolidation processes were recently described in Science. On the psychological level, reconsolidation is useful for explaining false and biased memories. Reconsolidation also leads to a memory model called multiple-trace theory: Every time a memory is reactivated, a new version of it is reconsolidated, leaving multiple traces of the same memory.

With respect to Karpicke and Roediger's study, we hypothesize that repeated testing (retrieval) should lead to multiple traces (due to repeated reconsolidation), which facilitate recall. Reinterpreting Karpicke and Roediger's results from a multiple-trace reconsolidation perspective supports this hypothesis and provides a new framework for explaining the effectiveness of frequent in-class assessments in pedagogies such as Peer Instruction.

Tuesday, July 01, 2008

The Toronto Village

A vacation picture...sidewalk cafe lunch at Maitland and Church streets.

Discontinuity between human and nonhuman minds?

In a recent issue of Brain and Behavioral Science (BBS) Penn, Holyoak and Povinelli argue for a profound difference in kind, not degree, between human and animal minds. Their suggestions elicit mainly vigorous opposition as well as some support from an array of commentators. Several of the commentators point out evidence for flexible relational capabilities within a physical symbol system exhibited by dolphins and birds. As I read through the debate and its mind-numbing detail I give up on trying to convey a succinct summary, but here is their abstract. (You might compare this with the work of Hauser et al, that I mentioned in a previous post.):

Over the last quarter century, the dominant tendency in comparative cognitive psychology has been to emphasize the similarities between human and nonhuman minds and to downplay the differences as “one of degree and not of kind” (Darwin 1871). In the present target article, we argue that Darwin was mistaken: the profound biological continuity between human and nonhuman animals masks an equally profound discontinuity between human and nonhuman minds. To wit, there is a significant discontinuity in the degree to which human and nonhuman animals are able to approximate the higher-order, systematic, relational capabilities of a physical symbol system (PSS) (Newell 1980). We show that this symbolic-relational discontinuity pervades nearly every domain of cognition and runs much deeper than even the spectacular scaffolding provided by language or culture alone can explain. We propose a representational-level specification as to where human and nonhuman animals' abilities to approximate a PSS are similar and where they differ. We conclude by suggesting that recent symbolic-connectionist models of cognition shed new light on the mechanisms that underlie the gap between human and nonhuman minds.

Most popular consciousness papers...

For April 2008, from the ASSC archive:

1. Destrebecqz, Arnaud and Peigneux, Philippe (2005) Methods for studying
unconscious learning. In: Progress in Brain Research. Elsevier, pp. 69-80.
1968 downloads from 26 countries. http://eprints.assc.caltech.edu/170/
2. Koriat, A. (2006) Metacognition and Consciousness. In: Cambridge handbook
of consciousness. Cambridge University Press, New York, USA. 1799 downloads
from 29 countries. http://eprints.assc.caltech.edu/175/
3. Sagiv, Noam and Ward, Jamie (2006) Crossmodal interactions: lessons from
synesthesia. In: Visual Perception, Part 2 - Fundamentals of Awareness:
Multi-Sensory Integration and High-Order Perception. Progress in Brain
Research, Volume 155. Elsevier, pp. 259-271. 1089 downloads from 18
countries. http://eprints.assc.caltech.edu/224/
4. Chalmers, David J. (2004) How can we construct a science of
consciousness? In: The Cognitive Neurosciences III. MIT Press, Cambridge,
MA. 1009 downloads from 9 countries. http://eprints.assc.caltech.edu/28/
5. Dehaene, Stanislas and Changeux, Jean-Pierre and Naccache, Lionel and
Sackur, Jérôme and Sergent, Claire (2006) Conscious, preconscious, and
subliminal processing: a testable taxonomy. Trends in Cognitive Science, 10
(5). pp. 204-211. 900 downloads from 13 countries.
http://eprints.assc.caltech.edu/20/