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.

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.

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.)

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.

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.

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.

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/

MindBlog on the road

This week, I'm starting a seven day vacation in Toronto with my partner Len. It is our 19th anniversary. The mindblog posts that appear will be using Blogger's neat new feature that permits the specification of a date in the future for a prepared posting to actually appear on the website.

Yesterday, Sunday, June 29, we hosted a social/musical at our home on Twin Valley road in the Town of Middleton, Wisconsin. Len does the food and I do the music. Over the next period of time, I will post here and on YouTube the music we played. Here is the invitation to the event, followed by a photo taken just before the music, and one during it:

Please join Deric and Len at the Twin Valley schoolhouse sunday afternoon, June 29, from 3 to 6 p.m. for conversation, wine, and Len's appetizers & h'orderves. If you like, bring a wine or other liquid to share.

Music at 4:00 p.m. (~45 min duration)
Two tangoes by Astor Piazzolla
Four movements from the two Mendelssohn piano trios.

Deric (piano), Daphne Tsao (violin) and Sonny Enslen (Cello)

Young and old brains differ in encoding positive information

A number of studies have revealed a "positivity shift" with aging; whereas young adults are more likely to remember negative information than positive or neutral information, older adults may be at least as likely (or even more likely) to remember positive information compared with negative information. It has been proposed that this "positivity shift" may occur because older adults put more emphasis on emotion regulation goals than do young adults, with older adults having a greater motivation to derive emotional meaning from life and to maintain positive affect. In the service of these goals, older adults may focus their attention on things that will elicit pleasant feelings and may process positive information in a more self-referential fashion. Thus this work (slightly edited) from Kensinger and Schacter probing the issue is of interest:

Young and older adults are more likely to remember emotional information than neutral information. The authors performed a magnetic resonance imaging study examining the neural processes supporting young (ages 18–35) and older (ages 62–79) adults' successful encoding of positive, negative, and neutral objects (e.g., a sundae, a grenade, a canoe). The results revealed general preservation of the emotional memory network across the age groups. Both groups recruited the amygdala and the orbito-frontal cortex during the successful encoding of positive and negative information. Both ages also showed valence-specific recruitment: right fusiform activity was greatest during the successful encoding of negative information, whereas left prefrontal and temporal activity was greatest during the successful encoding of positive information. These valence-specific processes are consistent with behavioral evidence that negative information is processed with perceptual detail, whereas positive information is processed at a conceptual or schematic level. The only age differences in emotional memory emerged during the successful encoding of positive items: Older adults showed more activity in the medial prefrontal cortex and along the cingulate gyrus than young adults. Because these regions often are associated with self-referential processing, these results suggest that older adults' mnemonic boost for positive information may stem from an increased tendency to process this information in relation to themselves.

Figure - Regions that showed a stronger correspondence to subsequent general recognition (i.e., subsequently recognized > subsequently forgotten) for the positive items than for the neutral or negative items. Red regions showed this correspondence for both young and older adults. Green regions showed this correspondence for the older adults but not for the young adults. No regions showed this correspondence for the young adults but not the older adults, consistent with the behavioral finding that only older adults showed mnemonic enhancement for the positive items.

ScienceHack - monkey brain moving robotic arm

I stumbled across this site with interesting science videos from a number of areas (biology, psychology, robotics, etc.). They are mainly at a superficial 'gee whiz' level, but quite engaging. Here is the Monkey moving a robotic arm. This is work from the Pittsburgh group, described in Nature, which promises to lead to effective therapy for human patients paralyzed by strokes, spinal-cord injuries and degenerative neuromuscular disease.

Best visual illusion of the year

Check out the Best Visual Illusion of the Year contest.....