Friday, January 31, 2014

The myth of cognitive decline with aging? Yes and No....

Offering something of an antidote to the drumbeat of articles measuring cognitive declines on again, Ramscar et al. (open source) suggest that changing performance patterns that are typically taken as evidence for (and measures of) cognitive decline arise out of basic principles of learning and emerge naturally in learning models as they acquire more knowledge, with patterns of performance reflect the information-processing costs that must inevitably be incurred as knowledge is acquired. Their arguments seem relevant to lexical tasks such as recalling words, but are not germane to declines in visual or auditory attention and processing speed (usually described as 'cognitive' declines) for which underlying brain structural and functional correlates have been observed. They also do not address the issue of noise, or competition from competing memories, as influencing lexical retrieval tasks. The second abstract below, work of Healey et al., notes this possibility. So, first the Ramscar et al. abstract:
As adults age, their performance on many psychometric tests changes systematically, a finding that is widely taken to reveal that cognitive information-processing capacities decline across adulthood. Contrary to this, we suggest that older adults'; changing performance reflects memory search demands, which escalate as experience grows. A series of simulations show how the performance patterns observed across adulthood emerge naturally in learning models as they acquire knowledge. The simulations correctly identify greater variation in the cognitive performance of older adults, and successfully predict that older adults will show greater sensitivity to fine-grained differences in the properties of test stimuli than younger adults. Our results indicate that older adults'; performance on cognitive tests reflects the predictable consequences of learning on information-processing, and not cognitive decline. We consider the implications of this for our scientific and cultural understanding of aging.
And now the Healey et al. abstract on noise or interference resolution by younger but not older adults:
Resolving interference from competing memories is a critical factor in efficient memory retrieval, and several accounts of cognitive aging suggest that difficulty resolving interference may underlie memory deficits such as those seen in the elderly. Although many researchers have suggested that the ability to suppress competitors is a key factor in resolving interference, the evidence supporting this claim has been the subject of debate. Here, we present a new paradigm and results demonstrating that for younger adults, a single retrieval attempt is sufficient to suppress competitors to below-baseline levels of accessibility even though the competitors are never explicitly presented. The extent to which individual younger adults suppressed competitors predicted their performance on a memory span task. In a second experiment, older adults showed no evidence of suppression, which supports the theory that older adults’ memory deficits are related to impaired suppression.

After I composed the above post Benedict Carey's mention of the Ramscar et al. article appeared in the NYTimes and became a 'most emailed article' for several days. He makes the same points that I do as a counter to over-interpreting Ramscar et al.'s data.

Thursday, January 30, 2014

Most published scientific results are false.

I would highly recommend reading this article by George Johnson, which points in particular to the work of John P. A. Ioannidis, a kind of meta-scientist who researches research, who wrote a 2005 paper pointedly titled “Why Most Published Research Findings Are False.” Here is one clip from the Johnson article:
If one of five competing labs is alone in finding an effect, that result is the one likely to be published. But there is a four in five chance that it is wrong. Papers reporting negative conclusions are more easily ignored...Putting all of this together, Dr. Ioannidis devised a mathematical model supporting the conclusion that most published findings are probably incorrect....the same year he published another blockbuster, examining more than a decade’s worth of highly regarded papers — the effect of a daily aspirin on cardiac disease, for example, or the risks of hormone replacement therapy for older women. He found that a large proportion of the conclusions were undermined or contradicted by later studies.
His work was just the beginning. Concern about the problem has reached the point that the journal Nature has assembled an archive, filled with reports and analyses, called Challenges in Irreproducible Research.. Among them is a paper in which C. Glenn Begley, who is chief scientific officer at TetraLogic Pharmaceuticals, described an experience he had while at Amgen, another drug company. He and his colleagues could not replicate 47 of 53 landmark papers about cancer. Some of the results could not be reproduced even with the help of the original scientists working in their own labs....Given what is at stake, it seems like a moral failing that the titles of the papers were not revealed. That was forbidden, we’re told, by confidentiality agreements imposed by the labs.

Wednesday, January 29, 2014

Mindfulness has so totally gone mainstream…..

Mindfulness at Davos
Mindfulness - the Time Magazine cover story

Enriched environments enhance adult brain plasticity.

I learned much of my neuroscience at tea time in Hubel and Wiesel's laboratory at Harvard Medical School during my post-doc days in the 1960's, as we discussed their discovery of critical periods during the development of ocular dominance columns in the visual cortex, and the apparent immutability of the adult pathways, once formed. Everything now has changed. We know our brains maintain their ability to make new nerve cells and connections throughout life. Greifzu et. al. add a new chapter to the plasticity story in their recent work showing how important enriched environments are in maintaining a younger brain that has not been locked into place by the increased inhibitory interactions characteristic of adult brains. Specifically, they show that ocular dominance columns can remain plastic in adult mice in enriched, but not ordinary cage, environments, and recover from stroke-induced damage or monocular deprivation.
Experimental animals are usually raised in small, so-called standard cages, depriving them of numerous natural stimuli. We show that raising mice in an enriched environment, allowing enhanced physical, social, and cognitive stimulation, preserved a juvenile brain into adulthood. Enrichment also rejuvenated the visual cortex after extended periods of standard cage rearing and protected adult mice from stroke-induced impairments of cortical plasticity. Because the local inhibitory tone in the visual cortex of adult enriched mice was not only significantly reduced compared with nonenriched animals but at juvenile levels, the plasticity-promoting effect of enrichment is most likely mediated by preserving low juvenile levels of inhibition into adulthood and thereby, extending sensitive phases of enhanced neuronal plasticity into an older age.

Tuesday, January 28, 2014

How inactivity changes the brain

Here is yet another sobering note for couch potatoes. Lack of exercise (in rats) causes undesirable remodeling of the brain. Gretchen Reynolds points to work by Mischel et al. (open source) showing that inactive versus active rats show changes in the region of the rostral ventrolateral medulla that regulates the sympathetic nervous system, increasing connectivity and reactivity, potentially overstimulating the sympathetic nervous system to constrict blood vessels, increase blood pressure, and thus enhance the possibility of cardiovascular disease. Here is the Mischel et al. abstract and a summary figure:
Increased activity of the sympathetic nervous system is thought to play a role in the development and progression of cardiovascular disease. Recent work has shown that physical inactivity versus activity alters neuronal structure in brain regions associated with cardiovascular regulation. Our physiological studies suggest that neurons in the rostral ventrolateral medulla (RVLM) are more responsive to excitation in sedentary versus physically active animals. We hypothesized that enhanced functional responses in the RVLM may be due, in part, to changes in the structure of RVLM neurons that control sympathetic activity. We used retrograde tracing and immunohistochemistry for tyrosine hydroxylase (TH) to identify bulbospinal catecholaminergic (C1) neurons in sedentary and active rats after chronic voluntary wheel-running exercise. We then digitally reconstructed their cell bodies and dendrites at different rostrocaudal levels. The dendritic arbors of spinally projecting TH neurons from sedentary rats were more branched than those of physically active rats (P < 0.05). In sedentary rats, dendritic branching was greater in more rostral versus more caudal bulbospinal C1 neurons, whereas, in physically active rats, dendritic branching was consistent throughout the RVLM. In contrast, cell body size and the number of primary dendrites did not differ between active and inactive animals. We suggest that these structural changes provide an anatomical underpinning for the functional differences observed in our in vivo studies. These inactivity-related structural and functional changes may enhance the overall sensitivity of RVLM neurons to excitatory stimuli and contribute to an increased risk of cardiovascular disease in sedentary individuals.

Physical inactivity versus activity is associated with functional changes in control of blood pressure by neurons in the rostral ventrolateral medulla (RVLM). The present study shows that putative cardiovascular RVLM neurons have more complex dendrites in inactive versus active rats. This anatomical difference may underpin the functional differences previously reported.

Monday, January 27, 2014

The liberal illusion of uniqueness

Bill Clinton is reported to have complained that getting Democrats to agree on a course of action was like herding cats, while the Republicans didn’t seem to have this problem. Stern et al. do a fascinating nugget of work that shows that conservatives and moderates overestimate the degree to which others conservative and moderates are like them, while those on the left end of the spectrum assume they are more unique among party peers than they actually are. (Recall the inability of the Occupy Wall Street movement in 2011 to achieve consensus on vital issues.) The authors used well-validated methodology for examining truly false consensus and truly false uniqueness effects by developing a procedure in which participants were asked to indicate their beliefs and their preferences for a series of items and then estimate the beliefs and preferences of political in-group members. To test for truly false uniqueness and truly false consensus effects, They compared the extent to which participants perceived that political in-group members shared their beliefs and preferences with the extent to which political in-group members actually shared participants’ beliefs and preferences. From their methods section:
We conducted two studies in which participants reported their beliefs and preferences and estimated the beliefs and preferences of political in-group members who were either fellow participants in the study (Study 1) or members of the general American population (Study 2). This procedure allowed us to examine whether similar patterns of effects would emerge even when participants thought about political in-group members in different contexts. In Study 2, we replicated and extended Study 1 by examining whether the desire to feel unique explains in part ideological differences in estimating similarity to political in-group members. Finally, previous research has shown that individuals perceive more similarity between their own beliefs and those of other individuals (i.e., perceive greater consensus) when the beliefs are socially desirable or personally important. To rule out the possibility that these factors explain ideological differences in perceiving similarity to political in-group members, we measured the perceived social desirability of the items to which participants responded in both studies. In addition, in Study 2, we measured the personal importance of the items to rule out the possibility that this factor would explain ideological differences in perceiving similarity.
Here is their brief abstract.
In two studies, we demonstrated that liberals underestimate their similarity to other liberals (i.e., display truly false uniqueness), whereas moderates and conservatives overestimate their similarity to other moderates and conservatives (i.e., display truly false consensus; Studies 1 and 2). We further demonstrated that a fundamental difference between liberals and conservatives in the motivation to feel unique explains this ideological distinction in the accuracy of estimating similarity (Study 2). Implications of the accuracy of consensus estimates for mobilizing liberal and conservative political movements are discussed.

Friday, January 24, 2014

The Kerfuffle over whether men and women's brains are different.

Nothing kicks up a firestorm in the Neuroscience blogosphere like talk of sex differences in brain architecture. Within days of PNAS's early December 2013 publication of what may be a landmark paper on the differing 'connectomes' (nerve fiber tracts connecting different brain areas) of 428 male and 521 female 8-22 year old humans, a storm of criticism of the work was bouncing around the internet, along with accusations of 'neurosexism'. (see, for example, here, here, here, and here.)

The critics make many points - 1. Men have bigger brains on average than women, possibly conflating results; 2. Maybe men and women move their heads differently while in the MRI machine; 3. The structural differences don't necessarily correlate with behavioral differences, and there are varying results on whether the structural results correlate with cognitive function tests. It is unfortunate that the authors of the study were spouting gender seems to me that the objections are mainly nit-picking, the data are rather compelling on fundamental differences in sexual connectivity that arise from genetic/environmental/cultural factors during brain development. (There is no such thing as 'hard wiring'.):
The results establish that male brains are optimized for intrahemispheric and female brains for interhemispheric communication. The developmental trajectories of males and females separate at a young age, demonstrating wide differences during adolescence and adulthood...The brains of men exhibit a far smaller degree of interconnectedness, both within and across the hemispheres, than do those of women.
I decided to wait for the dust to settle a bit, and let the final publication appear, and sure enough in the same issue there is an essay commentary by Larry Cahill that argues essentially that the politically correct view in brain research has been to assume no significant difference between male and female brain, and to assume results obtained (mainly for male brains) apply also to female brains.  Mouse studies in particular have shown that this is not the case.
...we now know that sex influences—small to medium to large—are extremely widespread on brain function. The validity of the assumption that the sex of subjects cannot powerfully alter, negate, and even reverse findings (hence, conclusions) has been crushed under the weight of evidence proving that it can and regularly does and at every level of investigation down to genes, single neurons, and even ion channels...For neuroscientists cognizant of this striking development, the main challenge now is to better understand the dizzying plethora of sex influences being uncovered. Males and females appear to be two complex mosaics, similar in some respects, mildly to highly different in others
Here is Cahill's summary comment:
A comedian discussing men and women once described the male brain as a bunch of boxes that don’t touch one another and the female brain as a complex ball of interconnected wires. Amusing as the bit was, the analogies may be more apt than he could have known. The findings of Ingahalikar et al. do indeed point to a greater degree of modular function in the physical architecture of the male brain and of interconnectedness in physical architecture of the female brain. Given the size of the study, the consistency of the conclusions across various analytic approaches, and the seeming concordance of key findings with well-established literature addressing brain function, one cannot fairly accuse Ingalhalikar et al. of hyperbole when they claim that their findings “reveal fundamental sex differences in the architecture of the human brain.” Theirs is a landmark paper that should accelerate acceptance of the notion that, for those who want to understand how brains function, sex matters.
And here, finally, is the Ingalhalikar et al. abstract:
Sex differences in human behavior show adaptive complementarity: Males have better motor and spatial abilities, whereas females have superior memory and social cognition skills. Studies also show sex differences in human brains but do not explain this complementarity. In this work, we modeled the structural connectome using diffusion tensor imaging in a sample of 949 youths (aged 8–22 y, 428 males and 521 females) and discovered unique sex differences in brain connectivity during the course of development. Connection-wise statistical analysis, as well as analysis of regional and global network measures, presented a comprehensive description of network characteristics. In all supratentorial regions, males had greater within-hemispheric connectivity, as well as enhanced modularity and transitivity, whereas between-hemispheric connectivity and cross-module participation predominated in females. However, this effect was reversed in the cerebellar connections. Analysis of these changes developmentally demonstrated differences in trajectory between males and females mainly in adolescence and in adulthood. Overall, the results suggest that male brains are structured to facilitate connectivity between perception and coordinated action, whereas female brains are designed to facilitate communication between analytical and intuitive processing modes.

Thursday, January 23, 2014

Bodily maps of emotions.

Nummenmaa and collaborators, from several universities in Finland, propose that our emotions are represented in our somatosensory system as culturally universal categorical somatotopic maps.
Emotions are often felt in the body, and somatosensory feedback has been proposed to trigger conscious emotional experiences. Here we reveal maps of bodily sensations associated with different emotions using a unique topographical self-report method. In five experiments, participants (n = 701) were shown two silhouettes of bodies alongside emotional words, stories, movies, or facial expressions. They were asked to color the bodily regions whose activity they felt increasing or decreasing while viewing each stimulus. Different emotions were consistently associated with statistically separable bodily sensation maps across experiments. These maps were concordant across West European and East Asian samples. Statistical classifiers distinguished emotion-specific activation maps accurately, confirming independence of topographies across emotions. We propose that emotions are represented in the somatosensory system as culturally universal categorical somatotopic maps. Perception of these emotion-triggered bodily changes may play a key role in generating consciously felt emotions.

Figure - Bodily topography of basic (Upper) and nonbasic (Lower) emotions associated with words. The body maps show regions whose activation increased (warm colors) or decreased (cool colors) when feeling each emotion.

Wednesday, January 22, 2014

The morning morality effect.

Here is an interesting tidbit from Kouchaki1 and Smith:
Are people more moral in the morning than in the afternoon? We propose that the normal, unremarkable experiences associated with everyday living can deplete one’s capacity to resist moral temptations. In a series of four experiments, both undergraduate students and a sample of U.S. adults engaged in less unethical behavior (e.g., less lying and cheating) on tasks performed in the morning than on the same tasks performed in the afternoon. This morning morality effect was mediated by decreases in moral awareness and self-control in the afternoon. Furthermore, the effect of time of day on unethical behavior was found to be stronger for people with a lower propensity to morally disengage. These findings highlight a simple yet pervasive factor (i.e., the time of day) that has important implications for moral behavior.

Tuesday, January 21, 2014

The milliseconds of a choice - Watching your mind when it matters.

This is actually a post about mindfulness, in reaction to Dan Hurley's article describing how contemporary applications of the ancient tradition of mindfulness meditation are being engaged in many more contexts than the initial emphasis on chilling out in the 1970s, and being employed for very practical purses such as mental resilience in a war zone. It seems like to me that we are approaching a well defined technology of brain control whose brain basis is understood in some detail. I've done numerous posts on behavioral and brain correlates of mindfulness meditation (enter 'meditation' or 'mindfulness' in MindBlog's search box in the left column). For example, only four weeks of a mindfulness meditation regime emphasizing relaxation of different body parts correlates with increases in white matter (nerve tract) efficiency. Improvements in cognitive performance, working memory, etc. have been claimed. A special issue of The journal Social Cognitive and Affective Neuroscience discusses issue in the research.

Full time mindfulness might be a bad idea, suppressing the mind wandering that facilitates bursts of creative insight. (During my vision research career, my most original ideas popped up when I was spacing out, once when I was riding a bike along a lakeshore path.) Many physicists and writers reports their best ideas happen when they are disengaged. It also appears that mindfulness may inhibit implicit learning in which habits and skill are acquired without conscious awareness.

Obviously knowing whether we are in an attentional or mind wandering (default, narrative) modes is useful (see here, and here), and this is where the title of this posts comes in. To note and distinguish our mind state is most effectively accomplished with a particular style of alertness or awareness that is functioning very soon (less than 200 milliseconds) after a new thought or sensory perception appears to us. This is a moment of fragility that offers a narrow time window of choice over whether our new brain activity will be either enhanced or diminished in favor of a more desired activity. This is precisely what is happening in mindfulness meditation that instructs a central focus of some sort (breathing, body relaxation, or whatever) to which one returns as soon as one notes that any other thoughts or distractions have popped into awareness. The ability to rapidly notice and attend to thoughts and emotions of these short time scales is enhanced by brain training regimes of the sort offered by BrainHq of and others. I have found the exercises on this site, originated by Michael Merznich, to be the most useful.  It offers summaries of changes in brain speed, attention, memory, intelligence, navigation, etc. that result from performing the exercises - changes that can persist for years.

A book title that has been popping into my head for at least the last 15 years is "The 200 Millisecond Manager." (a riff on the title the popular book of the early 1980's by Blanchard and Johnson, "The One Minute Manager.") The gist of the argument would be that given in the "Guide" section of some 2005 writing, and actually in Chapter 12 of my book, Figure 12-7.

It might make the strident assertion that the most important thing that matters in regulating our thoughts, feelings, and actions is their first 100-200 msec in the brain, which is when the levers and pulleys are actually doing their thing. It would be a nuts and bolts approach to altering - or at least inhibiting - self limiting behaviors. It would suggest that a central trick is to avoid taking on on the ‘enormity of it all,’ and instead use a variety of techniques to get our awareness down to the normally invisible 100-200 msec time interval in which our actions are being programmed. Here we are talking mechanics during the time period is when all the limbic and other routines that result from life script, self image, temperament, etc., actually can start-up. The suggestion is that you can short circuit some of this process if you bring awareness to the level of observing the moments during which a reaction or behavior is becoming resident, and can sometimes say “I don’t think so, I think I'll do something else instead.”

"The 200 msec Manager" has gone through the ‘this could be a book’ cycle several times, the actual execution  bogging down as I actually got into description of the underlying science and techniques for expanding awareness. Also, I note the enormous number of books out there on meditation, relaxation, etc. that are all really addressing the same core processes in different ways.

Monday, January 20, 2014

Beauty at the ballot box.

From White et al.:
Why does beauty win out at the ballot box? Some researchers have posited that it occurs because people ascribe generally positive characteristics to physically attractive candidates. We propose an alternative explanation—that leadership preferences are related to functional disease-avoidance mechanisms. Because physical attractiveness is a cue to health, people concerned with disease should especially prefer physically attractive leaders. Using real-world voting data and laboratory-based experiments, we found support for this relationship. A first study revealed that congressional districts with elevated disease threats, physically attractive candidates are more likely to be elected. A second study found that experimentally activating disease concerns leads people to especially value physical attractiveness in leaders and a third study showed they prefer more physically attractive political candidates. In a final study, we demonstrated that these findings are related to leadership preferences, specifically, rather than preferences for physically attractive group members more generally. Together, these findings highlight the nuanced and functional nature of leadership preferences.

Friday, January 17, 2014

Signals from inside and outside our bodies in self consciousness

Olaf Blanke (whose work on projecting ourselves outside our bodies I've mentioned previously) and collaborators extend their studies on body perception and self consciousness to show that signals from both the inside and the outside of the body are fundamental in determining our self consciousness:
Prominent theories highlight the importance of bodily perception for self-consciousness, but it is currently not known whether bodily perception is based on interoceptive or exteroceptive signals or on integrated signals from these anatomically distinct systems. In the research reported here, we combined both types of signals by surreptitiously providing participants with visual exteroceptive information about their heartbeat: A real-time video image of a periodically illuminated silhouette outlined participants’ (projected, “virtual”) bodies and flashed in synchrony with their heartbeats. We investigated whether these “cardio-visual” signals could modulate bodily self-consciousness and tactile perception. We report two main findings. First, synchronous cardio-visual signals increased self-identification with and self-location toward the virtual body, and second, they altered the perception of tactile stimuli applied to participants’ backs so that touch was mislocalized toward the virtual body. We argue that the integration of signals from the inside and the outside of the human body is a fundamental neurobiological process underlying self-consciousness.

Experimental setup for the body conditions. Participants (a) stood with their backs facing a video camera placed 200 cm behind them (b). The video showing the participant’s body (his or her “virtual body”) was projected in real time onto a head-mounted display. An electrocardiogram was recorded, and R peaks were detected in real time (c), triggering a flashing silhouette outlining the participant’s virtual body (d). The display made it appear as though the virtual body was standing 200 cm in front of the participant (e). After each block, participants were passively displaced 150 cm backward to the camera and were instructed to walk back to the original position.

Thursday, January 16, 2014

A reason for the power of prayer.

Friesea and Wänke find one source of the power of prayer that is not supernatural: it enhances self control by buffering self-control depletion, that is, protecting from breakdowns of will. In a sequential experimental paradigm, subjects were told to watch a humorous video but stifle emotional responses (this causes cognitive depletion) and then performed the stroop task, in which they indicated the ink color of words spelling various color, with the words being either consistent or inconsistent with their actual colors. Studies have shown that this task is harder after cognitive depletion. Both religious and non-religious who were asked to pray about a topic of their choosing for five minutes showed significantly better performance on the stroop task after emotion suppression, compared to participants who were simply asked to think about a topic of their choosing. The authors suggest that people might interpret prayer as a social interaction with a deity, with that social interaction enhancing cognitive resources. Other studies have found that social interaction enhances general cognitive functioning. Here is the Friesea and Wänke abstract:
The strength model of self-control has inspired large amounts of research and contributed to a deeper understanding of the temporal dynamics underlying self-control. Several studies have identified factors that can counteract self-control depletion, but relatively little is known about factors that can prevent depletion effects. Here we tested the hypothesis that a brief period of personal prayer would buffer self-control depletion effects. Participants either briefly prayed or thought freely before engaging (or not engaging) in an emotion suppression task. All participants completed a Stroop task subsequently. Individuals who had thought freely before suppressing emotions showed impaired Stroop performance compared to those who had not suppressed emotions. This effect did not occur in individuals who had prayed at the beginning of the study. These results are consistent with and contribute to a growing body of work attesting to the beneficial effects of praying on self-control.

Wednesday, January 15, 2014

Left spatial neglect goes with neglecting the “Left Side” of time.

An interesting observation from Saj et al.:
Previous research suggests that people construct mental time lines to represent and reason about time. However, is the ability to represent space truly necessary for representing events along a mental time line? Our results are the first to demonstrate that deficits in spatial representation (as a function of left hemispatial neglect) also result in deficits in representing events along the mental time line. Specifically, we show that patients with left hemispatial neglect have difficulty representing events that are associated with the past and, thus, fall to the left on the mental time line. These results demonstrate that representations of space and time share neural underpinnings and that representations of time have specific spatial properties (e.g., a left and a right side). Furthermore, it appears that intact spatial representations are necessary for at least some types of temporal representation.

Tuesday, January 14, 2014

How the brains of virtuosic pianists are different...

Because I'm a performing classical pianist (in fact, giving a concert on Feb. 9 in Fort Lauderdale, my snowbird roost from mid-October to mid_April), I always perk up when I come across articles showing how the brains of experienced pianists or other musicians are different from the brains of non-musicians. Candidi et al. make the interesting observation that the refined somatosensory and motor skills of musicians provide the brain with fine anticipatory, simulative error monitoring systems that are absent in non-pianist naive individuals.
Virtuosic musical performance requires fine sensorimotor skills and high predictive control of the fast finger movements that produce the intended sounds, and cannot be corrected once the notes have been played. The anticipatory nature of motor control in experts explains why musical performance is barely affected by auditory feedback. Using single-pulse transcranial magnetic stimulation, In a first experiment we provide evidence that, in expert pianists, the observation of a mute piano fingering error induces 1) a time-locked facilitation of hand corticospinal representation which occurred 300 and 700 ms but not 100 ms after error onset, and 2) a somatotopic corticospinal facilitation of the very same finger that commits the error. In a second experiment, we show that no corticospinal modulation is found in non-pianist naïve individuals who were experimentally trained to visually detect the observed fingering errors. This is the first evidence showing that the refined somatosensory and motor skills of musicians exceed the domain of individual motor control and may provide the brain with fine anticipatory, simulative error monitoring systems for the evaluation of others’ movements.

Monday, January 13, 2014

The social life of our genes - the devastating effects of social isolation

David Dobbs has done a broad and accessible review of how completely the expression of the genes regulating behavior are controlled by the social milieu, giving examples for bees, birds, fish, primates, and humans. Social conditions can change our gene expression with a rapidity, breadth, and depth previously overlooked. Humans, and other animals, most likely have this evolved capability because an organism that responds quickly to fast-changing social environments will more likely survive them. Dobbs points in particular to work by work by Steve Cole on social regulation of gene expression. Cole analyzed the relationship between social factors and human gene expression by surveying transcriptional profiles in white blood cells (leukocytes) from healthy older adults who differed in the extent to which they felt socially connected to others.
Among the 22,283 genes assayed, 209 showed systematically different levels of expression in people who reported feeling lonely and distant from others consistently over the course of 4 years (see Figure). These effects did not involve a random smattering of all human genes, but focally affected three specific groups of genes. Genes supporting the early “accelerator” phase of the immune response—inflammation—were selectively up-regulated; and two groups of genes involved in the subsequent “steering” of immune responses—genes involved in responses to viral infections (particularly Type I interferons), and genes involved in the production of antibodies by B lymphocytes—were down-regulated. These results provided a molecular framework for understanding why socially isolated individuals show heightened vulnerability to inflammation-driven cardiovascular diseases (i.e., excessive nonspecific immune activity) and impaired responses to viral infections and vaccines (i.e., insufficient immune responses to specific pathogens). A major clue about the psychological pathways mediating these effects came from the observation that differential gene-expression profiles were most strongly linked to a person's subjective sense of isolation rather than to their objective number of social contacts.

Figure: Gene expression in human immune cells in lonely and socially integrated people. Expression of 22,283 human gene transcripts was assayed in 10 million blood leukocytes sampled from each of 14 older adults who showed consistent differences over 4 years in their level of subjective social isolation. Two hundred nine gene transcripts showed at least 30% difference in average expression level between six people experiencing chronic social isolation and eight experiencing consistent social integration. In the heat-plot above, each row represents data from one of the 14 study participants, each column contains expression values for one of the 209 differentially active genes, and the coloring of each cell represents the relative level of that gene's expression in a given participant's leukocyte sample: Red = high expression, Black = intermediate expression, Green = low expression.

Friday, January 10, 2014

Social Darwinism isn't dead - the rich really do think they are different...

An engaging piece by Matthew Hutson in Slate points to work by Kraus and Keltner. Some clips:
...In 2012 the top 0.01 percent of households earned an average of $10.25 million, while the mean household income for the country overall was $51,000. Are top earners 200 times as smart as the rest of the field? Doubtful. Do they have the capacity to work 200 times more hours in the week? Even more doubtful.
..say you’re in that top 0.01 percent—or even the top 50 percent. Would you want to admit happenstance as a benefactor? Wouldn’t you rather believe that you earned your wealth, that you truly deserve it? Wouldn’t you like to think that any resources you inherited are rightfully yours, as the descendant of fundamentally exceptional people? .. you might even adjust your ideas about the power of genes. The lower classes are not merely unfortunate, according to the upper classes; they are genetically inferior.
Kraus and Keltner's work explores "social class essentialism" - the belief that surface differences can be explained by differences in fundamental identities. Studies have shown that
...people hold essentialist beliefs about generally biological categories such as gender, race, and sexuality, as well as about more cultural ones such as nationality, religion, and political orientation. Essentialism leads to stereotyping, prejudice, and a disinclination to mingle with outsiders.
Kraus and Keltner wanted to know if we see social class as an essential category. They found:
...that higher social class was associated with greater social class essentialism. This pattern remained even after controlling for political orientation as well as objective measures of a participant’s income and education level, indicating that it’s one’s sense of being above or below others, not one’s actual resources, that drives the result...the higher people perceived their social class to be, the more strongly they endorsed just-world beliefs (i.e. that the world is a fair place), and that this difference explained their increased social class essentialism: Apparently if you feel that you’re doing well, you want to believe success comes to those who deserve it, and therefore those of lower status must not deserve it.
There is a grain to truth to social class essentialism; the few studies on the subject estimate that income, educational attainment, and occupational status are perhaps at least 10 percent genetic (and maybe much more). ..But that’s a far cry from saying “It is possible to determine one’s social class by examining his or her genes.” Such a statement ignores the role of wealth inheritance, the social connections one shares with one’s parents, or the educational opportunities family money can buy—not to mention strokes of good or bad luck (that are not tied to karma).
Social class essentialism is basically inciting social Darwinism. This distortion of Darwin’s theory of evolution, in one interpretation, is the belief that only the fit survive and thrive—and, further, that this process should be accepted or even accelerated by public policy...It might also entail belief in survival of the fittest as a desired end, given the results linking it to reduced support for restorative interventions... It’s an example of the logical fallacy known as the “appeal to nature”—what is natural is good. (If that were true, technology and medicine would be moral abominations.)

Thursday, January 09, 2014

Watching our brain remembering something.

This is kind of neat! Staresinaa et al. observe a part of our brain working at remembering something while we go on about our further activities unrelated to what we want to remember.
How is new information converted into a memory trace? Here, we used functional neuroimaging to assess what happens to representations of new events after we first experience them. We found that a particular part of the medial temporal lobe, a brain region known to be critical for intact memory, spontaneously reactivates these events even when we are engaged in unrelated activities. Indeed, the extent to which such automatic reactivation occurs seems directly related to later memory performance. This finding shows that we can now study the dynamics of memory processes for specific experiences during the “offline” periods that follow the initial learning phase.
Figure- Offline reactivation in the entorhinal cortex (ErC). (Left) Hand-drawn anatomical regions of interest (ROIs) shown for one participant. (Right) Reactivation of encoding representations is greater for later recalled (R) than forgotten (F) trials. Bars represent mean ± SE of the condition difference. *P = 0.013, one-tailed paired t test.

Wednesday, January 08, 2014

The "being happy" stress-out.

Oliver Burkeman (the author of “The Antidote: Happiness for People Who Can’t Stand Positive Thinking”) does an engaging article on how deliberate effort on the part of managers and other to generate fun,
...might have precisely the opposite effect, making people miserable and thus reaffirming one of the oldest observations about happiness: When you try too hard to obtain it, you’re almost guaranteed to fail.
Here are some further clips:
...corporations call upon a burgeoning industry of happiness consultants, who’ll construct a Gross Happiness Index for your workplace, then advise you on ways to boost it…Countless self-help bloggers offer tips for generating cheer among the cubicles…There’s nothing wrong with happiness at work. Enjoyable jobs are surely preferable to boring or unpleasant ones; moreover, studies suggest that happy employees are more productive ones. But it doesn’t follow that the path to this desirable state of affairs is through deliberate efforts.
...there’s evidence that this approach… can have precisely the opposite effect, making people miserable and thus reaffirming one of the oldest observations about happiness: When you try too hard to obtain it, you’re almost guaranteed to fail. the pressure to maintain a cheery facade in such workplaces can be stressful and exhausting in itself, a form of what the sociologist Arlie Russell Hochschild called “emotional labor.” In a 2011 study of workers at an Australian call center, where bosses championed the “3 Fs” (focus, fun and fulfillment), researchers found that many experienced the party atmosphere as a burden, not a boon.…
The problem here is an organizational version of the “paradox of hedonism,” best expressed by John Stuart Mill: “Ask yourself whether you are happy, and you cease to be so.” The attempt to impose happiness is self-sabotaging. Psychologists have shown that positive-thinking affirmations make people with low self-esteem feel worse; that patients with panic disorders can become more anxious when they try to relax; and that an ability to experience negative emotions, rather than struggling to exclude them, is crucial for mental health.
…managers should concentrate on creating the conditions in which a variety of personality types, from the excitable to the naturally downbeat, can flourish. That means giving employees as much autonomy as possible, and ensuring that people are treated evenhandedly. According to a recent Danish study, lack of fairness at work is a strong predictor of depression, and even heavy workloads don’t bring people down, provided their bosses are fair.

Tuesday, January 07, 2014

Oxytocin enhances brain function in children with autism.

Fascinating observations from Gordon et al, who find that that intranasal administration of oxytocin enhances activity in the brain for socially meaningful stimuli and attenuates its response to nonsocially meaningful stimuli in children with autism spectrum disorder (ASD), as measured via functional MRI. This raises the prospect of treatments that target the core social dysfunction in ASD, and might bring about long-term behavioral improvements.:
Following intranasal administration of oxytocin (OT), we measured, via functional MRI, changes in brain activity during judgments of socially (Eyes) and nonsocially (Vehicles) meaningful pictures in 17 children with high-functioning autism spectrum disorder (ASD). OT increased activity in the striatum, the middle frontal gyrus, the medial prefrontal cortex, the right orbitofrontal cortex, and the left superior temporal sulcus. In the striatum, nucleus accumbens, left posterior superior temporal sulcus, and left premotor cortex, OT increased activity during social judgments and decreased activity during nonsocial judgments. Changes in salivary OT concentrations from baseline to 30 min postadministration were positively associated with increased activity in the right amygdala and orbitofrontal cortex during social vs. nonsocial judgments. OT may thus selectively have an impact on salience and hedonic evaluations of socially meaningful stimuli in children with ASD, and thereby facilitate social attunement. These findings further the development of a neurophysiological systems-level understanding of mechanisms by which OT may enhance social functioning in children with ASD.

Monday, January 06, 2014

A neural prosthesis can restore sensory-motor function after brain damage.

Guggenmos et al. use a brain–machine–brain interfaces (BMBIs) to reconnect two active brain regions whose connections had severed by damage to the brain area between them:
Closed-loop systems, or brain–machine–brain interfaces (BMBIs), have not been widely developed for brain repair. In this study, we targeted spared motor and somatosensory regions of the rat brain after traumatic brain injury for establishment of a functional bridge using a battery-powered microdevice. The results show that by using discriminated action potentials as a trigger for stimulating a distant cortical location, rapid recovery of fine motor skills is facilitated. This study provides strong evidence that BMBIs can be used to bridge damaged neural pathways functionally and promote recovery after brain injury. Although this study is restricted to a rodent model of TBI, it is likely that the approach will also be applicable to other types of acquired brain injuries.

Figure: Model of neuroprosthetic treatment approach after brain injury. (A) Normal connectivity of M1 (motor cortex), S1 (somatosensory cortex), and PM (premotor cortex). Both M1 (CFA in rat) and PM (RFA in rat) send substantial outputs to the spinal cord via the corticospinal tract. Also, extensive reciprocal connections exist between M1 and PM, as well as between M1 and S1. (B) Effects of focal M1 injury on brain connectivity and the hypothetical effect of a BMBI to restore somatosensory-motor communication. An injury to M1, as might occur in stroke or brain trauma, results in a focal area of necrosis, as well as loss of M1 outputs to the spinal cord. Corticocortical communication between M1 and S1 (and between M1 and PM) is also disrupted, further contributing to functional impairment. Because the uninjured PM also contains corticospinal neurons, it might have the ability to serve in a vicarious role. The dotted line indicates enhanced functional connection between PM and S1 that we propose is established after treatment with a BMBI. (C) Location of target areas in rat cerebral cortex. A topographic map of the somatosensory representation in S1 is superimposed on the cortex.

Friday, January 03, 2014

My aversion to "selfies" and the demographics of social media.

The actor James Franco has done an interesting brief essay on the meaning of "selfies", photos of himself reporting what he is doing relayed via Instagram. (Tumblr, Facebook, Pinterest, Twitter, Snapchat, and others,  are other common routes for selfies.)
...the self-portrait is an easy target for charges of self-involvement, but, in a visual culture, the selfie quickly and easily shows, not tells, how you’re feeling, where you are, what you’re doing….I am actually turned off when I look at an account and don’t see any selfies, because I want to know whom I’m dealing with. In our age of social networking, the selfie is the new way to look someone right in the eye and say, “Hello, this is me.”…We all have different reasons for posting them, but, in the end, selfies are avatars: Mini-Me’s that we send out to give others a sense of who we are.
I feel a complete aversion to the idea of advertising my daily life by posting pictures of myself as I move through a day.  It seems a violation of my privacy, a threat to periods of solitude and being alone that I value, and I wonder if this is a character trait that is increasingly rare in the millennial generation, which seems to have a fear of being alone.   … and this prompted me to do a cursory survey of the demographics of the users of some of these sites. I am not surprised to find that at age 71 I am on the much older side of a generational gap in behavior. One quickly finds that 90% of the 150 million people who are active on instagram are under the age of 35, urban, with a significant skew towards women. Facebook (which owns instagram) users are clustered in the 25-34 and over 55 age range. A table reported from the Pew research center shows the fraction of internet users who use various social networking sites.

Thursday, January 02, 2014

Cognitive Control - what you see depends on how you look.

Turk-Brown argues for a more expansive approach to understanding various kinds of non-invasive brain imaging data. I relay his abstract, and one figure describing how interactions between brain regions vary by cognitive state.
Noninvasive studies of human brain function hold great potential to unlock mysteries of the human mind. The complexity of data generated by such studies, however, has prompted various simplifying assumptions during analysis. Although this has enabled considerable progress, our current understanding is partly contingent upon these assumptions. An emerging approach embraces the complexity, accounting for the fact that neural representations are widely distributed, neural processes involve interactions between regions, interactions vary by cognitive state, and the space of interactions is massive. Because what you see depends on how you look, such unbiased approaches provide the greatest flexibility for discovery.

Fig. 2 Attentional modulation of functional connectivity. (A) The guided activation theory of cognitive control posits that prefrontal cortex (PFC) sends feedback to posterior cortex to switch connectivity between cortex and establish task-relevant pathways. (B) Such pathways exist in the visual cortex of nonhuman primates: V4 shows enhanced coherence with the area of V1 containing receptive fields for the attended target. (C) This mechanism also supports category-based selection in human visual cortex: V4 shows stronger background connectivity with the fusiform face area (FFA) when faces are attended and with the parahippocampal place area (PPA) when scenes are attended.