Essential role of default mode network in higher cognitive processing.

The respective roles of attentional and default mode networks in our brains has been the subject of numerous MindBlog posts (enter 'default mode' in the search box in the left column). A summary article by Bola and Borchardt notes an important recent contribution by Vatansever et al., whose abstract is shown below, followed by a graphic from the summary article.  Their work changes the previous view that the default mode disengages during goal-directed tasks.

ABSTRACT

The default mode network (DMN) has been traditionally assumed to hinder behavioral performance in externally focused, goal-directed paradigms and to provide no active contribution to human cognition. However, recent evidence suggests greater DMN activity in an array of tasks, especially those that involve self-referential and memory-based processing. Although data that robustly demonstrate a comprehensive functional role for DMN remains relatively scarce, the global workspace framework, which implicates the DMN in global information integration for conscious processing, can potentially provide an explanation for the broad range of higher-order paradigms that report DMN involvement. We used graph theoretical measures to assess the contribution of the DMN to global functional connectivity dynamics in 22 healthy volunteers during an fMRI-based n-back working-memory paradigm with parametric increases in difficulty. Our predominant finding is that brain modularity decreases with greater task demands, thus adapting a more global workspace configuration, in direct relation to increases in reaction times to correct responses. Flexible default mode regions dynamically switch community memberships and display significant changes in their nodal participation coefficient and strength, which may reflect the observed whole-brain changes in functional connectivity architecture. These findings have important implications for our understanding of healthy brain function, as they suggest a central role for the DMN in higher cognitive processing.

SIGNIFICANCE STATEMENT

The default mode network (DMN) has been shown to increase its activity during the absence of external stimulation, and hence was historically assumed to disengage during goal-directed tasks. Recent evidence, however, implicates the DMN in self-referential and memory-based processing. We provide robust evidence for this network's active contribution to working memory by revealing dynamic reconfiguration in its interactions with other networks and offer an explanation within the global workspace theoretical framework. These promising findings may help redefine our understanding of the exact DMN role in human cognition.

Graphic from Review

Schematic representation of the main findings of Vatansever et al. Community representation and colors are in the style of Figures 1 and 3 in the article by Vatansever et al. (2015), and the DMN is represented by Community 4. In the low-demanding 0-back condition, the network was highly modular (high Q index) and was divided into four distinct modules. With the increasing cognitive load, the modularity of the network decreased, and three communities merged into one. Thus, while local segregation was prevalent in the low-demanding task, increasing cognitive effort was associated with more pronounced global integration.

How to attract others.

Well, Duh...... Interesting, but talk about showing the obvious!.. from Vacharkulksemsuka et al.:

Across two field studies of romantic attraction, we demonstrate that postural expansiveness makes humans more romantically appealing. In a field study (n = 144 speed-dates), we coded nonverbal behaviors associated with liking, love, and dominance. Postural expansiveness—expanding the body in physical space—was most predictive of attraction, with each one-unit increase in coded behavior from the video recordings nearly doubling a person’s odds of getting a “yes” response from one’s speed-dating partner. In a subsequent field experiment (n = 3,000), we tested the causality of postural expansion (vs. contraction) on attraction using a popular Global Positioning System-based online-dating application. Mate-seekers rapidly flipped through photographs of potential sexual/date partners, selecting those they desired to meet for a date. Mate-seekers were significantly more likely to select partners displaying an expansive (vs. contractive) nonverbal posture. Mediation analyses demonstrate one plausible mechanism through which expansiveness is appealing: Expansiveness makes the dating candidate appear more dominant. In a dating world in which success sometimes is determined by a split-second decision rendered after a brief interaction or exposure to a static photograph, single persons have very little time to make a good impression. Our research suggests that a nonverbal dominance display increases a person’s chances of being selected as a potential mate.

Impulsivity, sensation seeking, and substance use correlate with reduced brain cortical thickness.

From Holmes et al.:

Individuals vary widely in their tendency to seek stimulation and act impulsively, early developing traits with genetic origins. Failures to regulate these behaviors increase risk for maladaptive outcomes including substance abuse. Here, we explored the neuroanatomical correlates of sensation seeking and impulsivity in healthy young adults. Our analyses revealed links between sensation seeking and reduced cortical thickness that were preferentially localized to regions implicated in cognitive control, including anterior cingulate and middle frontal gyrus (n = 1015). These associations generalized to self-reported motor impulsivity, replicated in an independent group (n = 219), and correlated with heightened alcohol, tobacco, and caffeine use. Critically, the relations between sensation seeking and brain structure were evident in participants without a history of alcohol or tobacco use, suggesting that observed associations with anatomy are not solely a consequence of substance use. These results demonstrate that individual differences in the tendency to seek stimulation, act on impulse, and engage in substance use are correlated with the anatomical structure of cognitive control circuitry. Our findings suggest that, in healthy populations, covariation across these complex multidimensional behaviors may in part originate from a common underlying biology.

Metaphorical conflict shapes social perception when spatial and ideological collide.

Kleiman et al. do some intriguing experiments. I give you their abstract first, which doesn't actually say how they did the experiments, and then give you some further description from their text. The abstract:

In the present article, we introduce the concept of metaphorical conflict—a conflict between the concrete and abstract aspects of a metaphor. We used the association between the concrete (spatial) and abstract (ideological) components of the political left-right metaphor to demonstrate that metaphorical conflict has marked implications for cognitive processing and social perception. Specifically, we showed that creating conflict between a spatial location and a metaphorically linked concept reduces perceived differences between the attitudes of partisans who are generally viewed as possessing fundamentally different worldviews (Democrats and Republicans). We further demonstrated that metaphorical conflict reduces perceived attitude differences by creating a mind-set in which categories are represented as possessing broader boundaries than when concepts are metaphorically compatible. These results suggest that metaphorical conflict shapes social perception by making members of distinct groups appear more similar than they are generally thought to be. These findings have important implications for research on conflict, embodied cognition, and social perception.

In the first experiment they asked subjects to categorize a series of pictures of Barack Obama and Mitt Romney. One group categorized the Romney pictures using their right hand (the P key)and Obama pictures with their left hand using the Q key - compatible with the right wing, left wing political metaphor. A second group was asked to identify Obama with their right hand and Romney with their left - in this case the physical action and the candidate's ideology were metaphorically incompatible. The interesting result was that:

...participants in the incompatible condition perceived the difference between the candidates’ ideologies as smaller than did participants in the compatible condition...Additionally, participants in the incompatible condition perceived the difference between the candidates’ stances on specific political issues as smaller than did participants in the compatible condition

A second experiment asked participants to estimate the ideology of the typical Democrat and Republican using a scale of 1 to 9 that was either compatible or incompatible with the metaphorical association linking spatial locations to political ideologies.

Participants assigned to the incompatible condition (n = 194) provided their response on a horizontally displayed scale with the values in the opposite sequence, that is, from 1 (extremely conservative) to 9 (extremely liberal). Note that this scale reversed the traditional spatial assignment and placed liberal views on the right and conservative views on the left, which metaphorically puts the physical location and ideology in conflict... consistent with predictions, participants who rated their perceptions on the incompatible scale perceived the typical Republican’s and typical Democrat’s attitudes as more similar than did participants who rated their perceptions on the compatible scale.

Two further control experiments were done.

Political polarization and prejudice.

Yesterday's post dealt with softening prejudicial attitudes towards transgender people. This is relevant to prejudice rising from the right versus left political polarization that continues to increase in this county. From a recent NYTimes OpEd piece by Arthur Brooks:

Thirty-eight percent of Democrats have a “very unfavorable” view of Republicans, and 43 percent of Republicans hold that view of Democrats. About half of “consistently liberal” Americans say most of their friends share their views, and about a third say it’s important to live in a place where that is so. For those who are “consistently conservative,” these preferences are even more pronounced.

...the average American is becoming more ideologically predictable. A Pew Research Center study from 2014 shows that the share of Americans with “consistently conservative” or “consistently liberal” views has more than doubled in the last two decades to 21 percent from 10 percent...In 1994, nearly 40 percent of Republicans were more liberal than the median Democrat, and 30 percent of Democrats were more conservative than the median Republican. Today, those numbers have plummeted to 8 percent and 6 percent.

This polarization has led to political discrimination that studies have shown to be stronger than racial discrimination

...Bigotry’s cousin is contempt...Watch and listen to politically polarized commentary today, and you will see that it is more contemptuous than angry, overflowing with sneering, mockery and disgust.

So what’s the antidote? I asked the Dalai Lama, one of the world’s experts on bringing people together. He made two points. First, the solution starts not with institutions, but with individuals. We look too much to political parties or Congress to make progress, but not nearly enough at our own behavior...You can’t single-handedly change the country, but you can change yourself. By declaring your independence from the bitterness washing over our nation, you can strike a small blow for greater national unity.

Second, each of us must aspire to what the Dalai Lama calls “warmheartedness” toward those with whom we disagree. This might sound squishy, but it is actually tough and practical advice. As he has stated, “I defeat my enemies when I make them my friends.” He is not advocating surrender to the views of those with whom we disagree. Liberals should be liberals and conservatives should be conservatives. But our duty is to be respectful, fair and friendly to all, even those with whom we have great differences.

Yesterday's post on changing prejudice suggests a further technique for reconciliation: active or analogic perspective taking. This is essentially imagining a situation in which you felt contempt from others, and also putting yourself in the shoes of others, imagining their concerns, etc.

How to change prejudice...for real this time

John Bohannon summarizes the interesting story of two researchers, who after finding that a study on reversing homophobia was based on fake data, went ahead to find that the effect claimed by the fraudulent study was real after all. Broockman and Kalla used a technique developed by the Los Angeles LGBT center:

...the LGBT Center has its canvassers follow one called “analogic perspective taking.” By inviting someone to discuss an experience in which that person was perceived as different and treated unfairly, a canvasser tries to generate sympathy for the suffering of another group—such as gay or transgender people.

Here is the abstract:

Existing research depicts intergroup prejudices as deeply ingrained, requiring intense intervention to lastingly reduce. Here, we show that a single approximately 10-minute conversation encouraging actively taking the perspective of others can markedly reduce prejudice for at least 3 months. We illustrate this potential with a door-to-door canvassing intervention in South Florida targeting antitransgender prejudice. Despite declines in homophobia, transphobia remains pervasive. For the intervention, 56 canvassers went door to door encouraging active perspective-taking with 501 voters at voters’ doorsteps. A randomized trial found that these conversations substantially reduced transphobia, with decreases greater than Americans’ average decrease in homophobia from 1998 to 2012. These effects persisted for 3 months, and both transgender and nontransgender canvassers were effective. The intervention also increased support for a nondiscrimination law, even after exposing voters to counterarguments.

Brain correlates of how the risk taking of others influences our own risk taking

From Suzuki et al., another upstairs/downstairs story. Risk is represented in the caudate nucleus (downstairs), the risk activity of others is represented in the dorsolateral prefrontal cortex (upstairs). The strength of the connections between these areas determines how susceptible our behavior is to influence by others.

Our attitude toward risk plays a crucial role in influencing our everyday decision-making. Despite its importance, little is known about how human risk-preference can be modulated by observing risky behavior in other agents at either the behavioral or the neural level. Using fMRI combined with computational modeling of behavioral data, we show that human risk-preference can be systematically altered by the act of observing and learning from others’ risk-related decisions. The contagion is driven specifically by brain regions involved in the assessment of risk: the behavioral shift is implemented via a neural representation of risk in the caudate nucleus, whereas the representations of other decision-related variables such as expected value are not affected. Furthermore, we uncover neural computations underlying learning about others’ risk-preferences and describe how these signals interact with the neural representation of risk in the caudate. Updating of the belief about others’ preferences is associated with neural activity in the dorsolateral prefrontal cortex (dlPFC). Functional coupling between the dlPFC and the caudate correlates with the degree of susceptibility to the contagion effect, suggesting that a frontal–subcortical loop, the so-called dorsolateral prefrontal–striatal circuit, underlies the modulation of risk-preference. Taken together, these findings provide a mechanistic account for how observation of others’ risky behavior can modulate an individual’s own risk-preference.

Aging brains - more physical activity, more gray matter, less Alzheimers.

I like to pass on any work I see relevant to exercise, aging, and the brain. The following is from Raji et al.

BACKGROUND: Physical activity (PA) can be neuroprotective and reduce the risk for Alzheimer's disease (AD). In assessing physical activity, caloric expenditure is a proxy marker reflecting the sum total of multiple physical activity types conducted by an individual. 

OBJECTIVE: To assess caloric expenditure, as a proxy marker of PA, as a predictive measure of gray matter (GM) volumes in the normal and cognitively impaired elderly persons. 

METHODS: All subjects in this study were recruited from the Institutional Review Board approved Cardiovascular Health Study (CHS), a multisite population-based longitudinal study in persons aged 65 and older. We analyzed a sub-sample of CHS participants 876 subjects (mean age 78.3, 57.5% F, 42.5% M) who had i) energy output assessed as kilocalories (kcal) per week using the standardized Minnesota Leisure-Time Activities questionnaire, ii) cognitive assessments for clinical classification of normal cognition, mild cognitive impairment (MCI), and AD, and iii) volumetric MR imaging of the brain. Voxel-based morphometry modeled the relationship between kcal/week and GM volumes while accounting for standard covariates including head size, age, sex, white matter hyperintensity lesions, MCI or AD status, and site. Multiple comparisons were controlled using a False Discovery Rate of 5 percent. 

RESULTS: Higher energy output, from a variety of physical activity types, was associated with larger GM volumes in frontal, temporal, and parietal lobes, as well as hippocampus, thalamus, and basal ganglia. High levels of caloric expenditure moderated neurodegeneration-associated volume loss in the precuneus, posterior cingulate, and cerebellar vermis. 

CONCLUSION: Increasing energy output from a variety of physical activities is related to larger gray matter volumes in the elderly, regardless of cognitive status.

Distraction in the digital era….what about since 1710?

I want to pass on some clips from an interesting essay by Frank Furedi, "The Ages of Distraction."

The rise of the internet and the widespread availability of digital technology has surrounded us with endless sources of distraction: texts, emails and Instagrams from friends, streaming music and videos, ever-changing stock quotes, news and more news. To get our work done, we could try to turn off the digital stream, but that’s difficult to do when we’re plagued by FOMO, the modern fear of missing out. Some people think that our willpower is so weak because our brains have been damaged by digital noise. But blaming technology for the rise in inattention is misplaced. History shows that the disquiet is fueled not by the next new thing but by the threat this thing – whatever it might be – poses to the moral authority of the day.

The first time inattention emerged as a social threat was in 18th-century Europe, during the Enlightenment, just as logic and science were pushing against religion and myth. The Oxford English Dictionary cites a 1710 entry from Tatler as its first reference to this word, coupling inattention with indolence; both are represented as moral vices of serious public concern.

The recent decades have seen a dramatic reversal in the conceptualization of inattention. Unlike in the 18th century when it was perceived as abnormal, today inattention is often presented as the normal state. The current era is frequently characterized as the Age of Distraction, and inattention is no longer depicted as a condition that afflicts a few. Nowadays, the erosion of humanity’s capacity for attention is portrayed as an existential problem, linked with the allegedly corrosive effects of digitally driven streams of information relentlessly flowing our way.

The perception of an Age of Distraction is related to our uncertainty about the answer to the question of ‘attention to what or to whom’. The sublimation of anxieties about moral authority through the fetish of technologically driven distraction has acquired pathological proportions in relation to children and young people. Yet as most sensible observers understand, children who are inattentive to their teachers are often obsessively attentive to the text messages that they receive. The constant lament about inattentive youth in the Anglo-American world could be interpreted as a symptom of problems related to the exercise of adult authority.

Often the failure to inspire and capture the imagination of young people is blamed on their inattentive state of minds. Too often educators have responded to this condition by adopting a fatalistic approach of accommodating to the supposed inattentive reading practices of digital natives. This pattern is evident in higher education where the assumption that college students can no longer be expected to read long and challenging texts or pay attention to serious lectures has led to the adaptation of course material to the inattentive mentality of the digital native. Calls to change the educational environment to ‘fit the student’ have become widespread in higher education.

How different from the reaction of moral philosophers such as Dugald Stewart, also concerned with the problem of the inattentive student. Author of Outlines of Moral Philosophy: For the Use of Students in the University of Edinburgh (1793), Stewart believed that the problem of inattention could be overcome through moral education. Unlike some contemporary academics, he regarded the ‘early habit of inattention’ a problem to be solved rather than an unalterable fact of existence. Helvétius fervently believed that everyone had the potential to acquire ‘continued attention’ and ‘triumph over indolence’.

Regrettably, the optimism of Helvétius has given way to a mood of resignation. Attention is still seen as desirable but almost impossible to achieve. As one alarmist account warns, ‘an epidemic erosion of attention is a sure sign of an impending dark age’. Helvétius would have been distressed by the fatalism expressed in this lament.

The evolutionary origins of smiles, laughter, and tears.

Graziano suggests that our smile originated in the defensive reaction of monkeys to other monkeys moving into their personal space. He then proceeds to make just-so stories about simian origins of our laughing and crying. To begin, imagine Monkey B steps into the personal space of Monkey A.

Monkey A squints, protecting his eyes. His upper lip pulls up. This does expose the teeth, but only as a side-effect: in a defensive reaction, the point of the curled lip is not to prepare for a biting attack so much as it is to bunch the facial skin upward, further padding the eyes in folds of skin...The head pulls down and the shoulders pull up to protect the vulnerable throat and jugular....The torso curves forward to protect the abdomen...Monkey B can learn a lot by watching the reaction of Monkey A...And so the stage is set for a social signal to evolve: natural selection will favour monkeys that can read the cringe reactions of their peers and adjust their behaviour accordingly...If Monkey B can glean useful information by watching Monkey A, then it’s useful for Monkey A to manipulate that information and influence Monkey B. Evolution therefore favours monkeys that can, in the right circumstances, pantomime a defensive reaction. It helps to convince others that you’re non-threatening. Finally we see the origin of the smile: a briefly flashed imitation of a defensive stance.

In people, the smile has been pared down to little more than its facial components — the lifting of the upper lip, the upward bunching of the cheeks, the squint. These days we use it mainly to communicate a friendly lack of aggression rather than outright subservience...We can’t help feeling warmer towards someone who beams that Duchenne smile.

On laughing:

...chimps have something like laughter: they open their mouths and make short exhalations during play fights, or if someone tickles them. Gorillas and orangutans do the same. The psychologist Marina Ross compared the noises made by different species of ape and found that it was the sound of bonobos at play that comes closest to human laughter, again, when play-fighting or tickling. All of which makes it seem quite likely that the original type of human laughter also emerged from, yes, play-fighting and tickling.

On crying:

My best guess, strange as it might sound, is that our ancestors were in the habit of punching each other on the nose. Such injuries would have resulted in copious tear production...According to recent analysis by David Carrier and Michael Morgan from Utah University, the shape of human facial bones might well have evolved to withstand the physical trauma of frequent punching. Thickly buttressed facial bones are first seen in fossils of Australopithecus, which appeared following our split with chimpanzees...the reason we weep now may well be that our ancestors discussed their differences by hitting each other in the face. Some of us still do, I suppose.

In any event, the entire behavioural display that we call crying – the tear production, the squinting, the raised upper lip, the repeated alarm calls – makes for a useful signifier. Evolution would have favoured animals that reacted to it with an emotional desire to dispense comfort.

Graziano's speculative summary:

An age-old defensive mechanism, a mechanism that monitors bubbles of space around the body and organises protective movements, suddenly takes flight in the hyper-social world of primates, spinning into smiles and laughter and crying and cringeing. Each one of those behaviours then splits further, branching into a whole codebook of signals for use in different social circumstances. Not all of human expression can be explained in this way, but much of it can. A Duchenne smile, a cold smile, laughter at a joke, laughter that acknowledges a clever witticism, cruel laughter, a cringe to show servility, standing straight to show confidence, the arms-crossed expression of suspicion, the arms-open expression of welcome, tilting your head as a sign of surrender to a lover, the fleeting crinkling of the face that hints at crying as we show sympathy for some sad story, or a full blown sobbing jag: this whole vast range of expression could well have emerged from a protective sensory-motor loop that has nothing to do with communication. Evolution is bizarre.

Another list - "Keys to happiness"

The New York Times has done a simple list of pointers to basic articles and research on well being. I'm passing on a few of the items from a condensed version of that list, rearranging the list in almost reverse order to reflect not importance, but items that seem to me to be less commonly acted on. So, keys of happiness:

Don't obsess about it, and don't overdo it.

If all else fails, fake it.

Gratitude helps.

Make friends, family, and weekends a priority

Be healthy

A succinct list of some of our common psychological errors.

I want to point to Belsky's article on why we think we are better decision makers under uncertainty than we really are. He summarizes several common errors:

The sunk cost fallacy - hanging on to a decision, or an investment, in an unconscious desire to justify it.

Loss aversion - reacting more strongly to loss of a resource (time, goods, or money) than to a similar gain.

Overconfidence - overrating our abilities, knowledge, and skill (two thirds of investors rate their financial sophistication as advanced, but barely pass a financial literacy exam.)

Optimism bias - which seems to be hard-wired into our brains because it has evolutionarily useful, driving humans to strive in the face of long odds.

Hindsight bias - rewriting history to make ourselves look good, as in misremembering our forecasts in a way that makes us look smarter.

Attribution bias - attributing good outcomes to our own skills, but bad outcomes to causes over which we had no control.

Confirmation bias - giving too much weight to information that supports our existing beliefs and discounting that which does not.

Muscle mass and nerve control enhanced in octogenarian athletes.

Power et al. expand their earlier studies on active runners ~65 years old to find ~14% greater muscle mass and ~28% more functioning motor nerve units in octogenarian masters athletes than in healthy age-matched controls.

Our group has shown a greater number of functioning motor units (MU) in a cohort of highly-active older(~65y) masters runners relative to age-matched controls. Owing to the precipitous loss in the number of functioning MUs in the 8th and 9th decade of life it is unknown whether older world class octogenarian masters athletes (MA) would also have greater numbers of functioning MUs (MUNE) compared with age-matched controls. We measured MU numbers and neuromuscular transmission stability in the tibialis anterior of world champion MAs (~80y), and compared the values to healthy age-matched controls (~80y). Decomposition-enhanced spike-triggered averaging was used to collect surface and intramuscular electromyography signals during dorsiflexion at ~25% of maximum voluntary isometric contraction(MVC). Near fibre (NF) MU potential analysis was used to assess neuromuscular transmission stability. For the MAs as compared with age-matched controls; the amount of excitable muscle mass (CMAP) was 14% greater (p less than 0.05), there was a trend (p=0.07) towards a 27% smaller surface detected motor unit potential - representative of less collateral reinnervation, and 28% more functioning MUs (p less than 0.05). Additionally, the MAs had greater MU neuromuscular stability than the controls as indicated by lower NF jitter and jiggle values (p less than 0.05). These results demonstrate that high performing octogenarians better maintain neuromuscular stability of the MU and mitigate the loss of MUs associated with aging well into the later decades of life during which time the loss of muscle mass and strength become functionally relevant. Future studies need to identify the concomitant roles genetics and exercise play in neuroprotection.

Why sad music can make us feel good.

As an update to a previous MindBlog post on why we like sad music, I want to note Ojiaku's brief mention of several articles on this subject.

Sad music might make people feel vicarious unpleasant emotions, found a study published last year in Frontiers in Psychology. But this experience can ultimately be pleasurable because it allows a negative emotion to exist indirectly, and at a safe distance. Instead of feeling the depths of despair, people can feel nostalgia for a time when they were in a similar emotional state: a non-threatening way to remember a sadness.

People who are very empathetic are more likely to take pleasure in the emotional experience of sad music, according to another study in Frontiers of Psychology. Others enjoy sad songs because they help them return to an emotionally balanced state, according to a review in Frontiers in Human Neuroscience, published in 2015. And those more open to varied experiences might enjoy the songs because the unique emotions that come up when listening to the music fulfill their need for novelty in thoughts and feelings.

From the Frontiers in Neurosciences abstract:

We offer a framework to account for how listening to sad music can lead to positive feelings, contending that this effect hinges on correcting an ongoing homeostatic imbalance. Sadness evoked by music is found pleasurable: (1) when it is perceived as non-threatening; (2) when it is aesthetically pleasing; and (3) when it produces psychological benefits such as mood regulation, and empathic feelings, caused, for example, by recollection of and reflection on past events.

The Social Gene

I want to pass on some clips from Joseph's Swift's review of a book, "The Society of Genes" by Yanai and Lercher that updates Richard Dawkins's classic "The Selfish Gene" publised 40 years ago. (Their title reminds me of "Society of Mind," a classic book published in 1986 by Marvin Minsky, who recently died at age 88.)

Genetic research has moved rapidly since the publication of Richard Dawkins's The Selfish Gene 40 years ago. In the intervening years, we have come to realize that many of the most interesting and important phenomena in human biology are not caused by any single gene. Processes like the immune system's ability to recognize infection, or the timing of our sleep-wake cycle, for example, are the product of many genes working together in a highly integrated way. Citing a wealth of recent research that explores the ways genes work together to produce complex biological processes, Itai Yanai and Martin Lercher argue that it is time to embrace a new, more holistic, metaphor in their book, The Society of Genes.

Rather than focus on any one gene, Yanai and Lercher invite the reader to step back and observe how genes assemble together to make a global genetic system, or genome. From here, one can see that the labor within the genome is not divided equally. Whereas many genes encode for proteins that perform a single monotonous task, such as breaking down a certain type of sugar or producing a specific skin pigment, there are others that serve such fundamental roles that their removal would lead to the crumbling of the genomic society altogether. Among the latter group are genes that manage the behavior of a host of other genes.

When genes are mismanaged by their masters, organisms can be transformed in dramatic ways. For example, in humans, when SOX9 fails to direct its wide range of subordinates succinctly, sex reversal and skeletal malformations can occur.

Given that catastrophic things tend to happen when genes don't work together properly, changes to how the genomic society is run are a rare occurrence. When genes with new abilities evolve, Darwinian selection determines whether they will join the ranks as productive members of society. Our ancestors obtained genes that could interpret light as color and a gene for a more efficient oxygen-carrying hemoglobin in this very way.

And then there are the genes that don't contribute to society at all. Instead, they secure their position by hijacking the system. The LINE1 gene, for example, encodes only for its own dispersal, copying and pasting itself throughout our genome while providing the society with no clear benefit. The “bad behavior” of genes amounts to scandal in the genomic society, and learning about their exploits is one of the most enjoyable elements of reading the book.

There are even genes that work to ensure the survival of individual cells within an organism by wreaking havoc on others. In fruit flies, for example, a pair of genes involved in sperm production work in concert to produce both a poison and its antidote. The toxic compound is released from the cell, while the antidote is retained. In this way, surrounding sperm cells without the gene pair are killed. On reading about such systems, one begins to realize that it's not quite right to imagine our genome as some idealized republic. This is a society that is easily compromised from within its own ranks.

In the years since The Selfish Gene was published, the human genome has been sequenced, along with the genomes of many other species. Indeed, probing one's own genes is beginning to become routine. Thus, The Society of Genes represents a timely and welcome handbook for navigating this postgenomic era.

Pterostilbene anti-aging supplement - undesirable side effects

In a January 15 MindBlog post, I noted the start of my most recent foray into supplements meant to have salutary effects on energy, mind, body, longevity, etc., giving some references to work on pterostilbene, a resveratrol cousin whose added methyl groups allow more rapid absorption after ingestion and slow down its removal by the liver. I’m wanting to report now on my experience of trying Elysium’s pills containing 125 mg pterostilbene and 25 mg nicotinamide riboside, (one per day, instead of the two recommended). I emphasize that this is a single report, people doubtless vary in their sensitivity.

I used the half dose because my previous 2008 experiment with resveratrol was terminated after 19 days because of increasing arthritic symptoms, especially in hands, which disappeared with a week after stopping the supplement. The MindBlog post reporting this result received 33 comments noting side effects of arthritic symptoms, foot and finger soreness and stiffness, sleep disturbance, joint pain, etc. All of these effects are consistent with possible immune system activation and inflammation. 

On starting one pill a day, I thought I noticed after a few days a subtle increase in body energy, a slightly more benign and positive temperament (there are a few reports of anxiolytic effects of low doses of pterostilbene), and most interesting to me, a decrease in rumination or mind wandering versus focused attention . By day 30 increasing stiffness in fingers and body movement was obvious. I terminated the pills, and stiffness disappeared over the next few days. After seven days off, I started one pill a day again. After four days, stiffness and arthritic symptoms had clearly increased in my hands. On stopping the pills again, stiffness disappeared over the next few days.

So, I guess that’s it for me on the resveratrol or pterostilbene trip. Pity… chemical studies noting their desirable effects are quite compelling. I do think Elysium and other vendors of these products should state their possible side effects.

Are we all sexists and racists?

I want to point to Miller's review of work of Levanon et al., as well as other studies, showing that that when women have moved into occupations in large numbers, those jobs have begun paying less even after controlling for education, work experience, skills, race and geography.

A striking example is to be found in the field of recreation — working in parks or leading camps — which went from predominantly male to female from 1950 to 2000. Median hourly wages in this field declined 57 percentage points, accounting for the change in the value of the dollar, according to a complex formula used by Professor Levanon. The job of ticket agent also went from mainly male to female during this period, and wages dropped 43 percentage points...The same thing happened when women in large numbers became designers (wages fell 34 percentage points), housekeepers (wages fell 21 percentage points) and biologists (wages fell 18 percentage points). The reverse was true when a job attracted more men. Computer programming, for instance, used to be a relatively menial role done by women. But when male programmers began to outnumber female ones, the job began paying more and gained prestige.

In the vein of work described in a previous MindBlog post, an excellent article by Ojiaku, a former Neuroscience Graduate Student at the University of Wisconsin, gives extensive references to work demonstrating that our unconscious racism starts early, and creates a deadly empathy gap. The studies Ojiaku cites:

...showed racially biased differences in cognitive and emotion-related brain regions, including the anterior cingulate cortex (ACC). One of the ACC’s functions is registering when you experience your own pain or empathy for another person’s pain. In the study, Chinese and Caucasian college students were shown video clips of both Chinese and Caucasian faces either in pain or not in pain as scientists conducted brain scans. The researchers measured increased ACC activity in the brains of those viewing painful expressions on the faces belonging to their own race, but decreased ACC activity when viewing pain in another race, uncovering a racially biased difference in empathetic response to pain in the brain.

Another study:

...asked participants to view video images of white, black, and violet-illuminated (for racially neutral) hands being pricked with a needle. While watching the prick, the volunteers were tested for their empathetic response via transcranial magnetic stimulation (TMS); the greater the reaction to the stimulation, the higher the empathetic response to the pain...Interestingly enough, both black and white participants had an adequately empathetic response to seeing the violet hand being pricked. However, all of the participants – both black and white – failed to react as strongly to the pain of someone who was outside their racial group. The study also found that people who scored higher in racial bias on the IAT (implicit association test) – meaning that they showed more implicit preferences for faces belonging to their own race – also showed less reactivity to pain experienced by someone from another race.

The last straw:

...is a study from the University of Iowa published in Psychological Science in February 2016. Incredibly, the researchers found that when white test subjects were primed with photos of five-year-old black boys, they were far more likely to mistake objects such as toys for guns – or even to claim to see guns when there were none. In sharp contrast, when subjects were primed with photos of five-year-old white boys before seeing the objects, the effect reserved, as they were more likely to mistake guns for toys. These findings are ominous for black children, because it shows that youth does not mitigate their potential to become targets of racist events, as in the case of the 12-year-old Tamir Rice, a young black boy carrying a toy ‘BB gun’ in a park in Cleveland, Ohio, whom the police shot in less than two seconds after arriving on the scene.

Another social science, Economics, looks at itself.

Mindblog recently noted a large study that tested the replicability of studies in psychology journals. Only 36% of the findings were repeated. The quality of results has also been questioned in many fields such as medicine, neuroscience, and genetics. Camerer et al. have now tested the replicability of experiments published in top-tier economics journals, finding that two-thirds of the 18 studies examined yielded replicable estimates of effect size and direction. Their abstract:

The replicability of some scientific findings has recently been called into question. To contribute data about replicability in economics, we replicated 18 studies published in the American Economic Review and the Quarterly Journal of Economics between 2011 and 2014. All of these replications followed predefined analysis plans that were made publicly available beforehand, and they all have a statistical power of at least 90% to detect the original effect size at the 5% significance level. We found a significant effect in the same direction as in the original study for 11 replications (61%); on average, the replicated effect size is 66% of the original. The replicability rate varies between 67% and 78% for four additional replicability indicators, including a prediction market measure of peer beliefs.

Overkill in techno-aids for 'Mens Sana in Corpore Sano'

None of us would argue with the 'sound mind in a sound body' injunction from Juvenal’s Latin satires (~100 AD), a goal that can be accomplished by diligent pursuit of a few simple activities. Two NYTimes articles note how modern technology manages, for a profit, to vastly encumber that pursuit.

With regard to 'sound mind,' Gelles notes:

The other morning, I woke up and brewed a cup of Mindful Lotus tea ($6 for 20 bags). On the subway, I loaded the Headspace app on my iPhone and followed a guided mindfulness exercise ($13 a month for premium content). Later in the day, I dropped by Mndfl, a meditation studio in Greenwich Village ($20 for a 30-minute class)...There are more than two dozen mindfulness apps for smartphones, some offering $400 lifetime subscriptions. The Great Courses has two mindfulness packages, each with a couple of dozen DVDs for $250. For an enterprising contemplative, it’s never been easier to make a buck...On a recent trip to Whole Foods, near the kombucha, I came across a new product from the health food maker Earth Balance: a dairy-free mayonnaise substitute called Mindful Mayo ($4.50 a jar). Then, in line, I picked up a copy of Mindful magazine ($6)....With so many mindful goods and services for sale, it can be easy to forget that mindfulness is a quality of being, not a piece of merchandise

...with so many cashing in on the meditation craze, it’s hard not to wonder whether something essential is being lost...Increasingly, mindfulness is being packaged as a one-minute reprieve, an interlude between checking Instagram and starting the next episode of “House of Cards.” One company proclaims it has found the “minimum effective dose” of meditation that will change your life. On Amazon, you can pick up “One-Minute Mindfulness: 50 Simple Ways to Find Peace, Clarity, and New Possibilities in a Stressed-Out World.” Dubious courses promise to help people “master mindfulness” in a few weeks.

More often than not, however, the people I know who take time to meditate — carefully observing thoughts, emotions and sensations — are sincere in their aspirations to become less stressed, more accepting and at least a little happier.

Hutchinson discusses the greater than billion dollar market for body fitness aids (which are not used by more than half their buyers six months after their purchase) suggesting:

...a more fundamental question about our rapid adoption of wearable fitness tech: Is the data we collect with these devices actually useful?...Last September, in The British Journal of Sports Medicine, Australian researchers published a review of studies that compared subjective and objective measures of “athlete well-being” during training. The objective measures included state-of-the-art monitoring of heart rate, blood, hormones and more; the subjective measure boiled down to asking the athletes how they felt. The results were striking: The researchers found that as the athletes worked out, their own perception registered changes in training stress with “superior sensitivity and consistency” to the high tech measures...running with a GPS watch “slackens the bond between perception and action.” In other words, when you’re running, instead of speeding up or slowing down based on immediate and intuitive feedback from your body and environment, you’re inserting an unwieldy extra cognitive step that relies on checking your device as you go.

On the positive side:

Health researchers also want to use your tracked data to figure out what works in the real world to improve health and fitness, rather than testing theories in the artificial conditions of the lab. An analysis of in-the-wild data from 4.2 million MyFitnessPal users, for example, recently yielded unexpected insights into the habits of successful weight-losers compared with unsuccessful ones: They ate nearly a third more fiber, and 11 percent less meat. And the dietary changes the successful dieters made between 2014 and 2015 bucked broader trends: They consumed more grains, cereal and raw fruit, but fewer eggs.

As prosaic as it sounds, this is the greatest promise of the wearables revolution. Once the novelty of tracking your exercise habits wears off, knowing how many steps you took today or what your resting heart rate was yesterday soon loses its interest. But together, 100 million of us wearing wristbands could uncover some truly valuable insights into what works to make us healthier and fitter.

Perhaps the most effective and simple way to increase aerobic fitness: use a jump rope!

Storing long term emotional memories.

A Journal of Neuroscience precis of an article by Cambiaghi et al., slightly edited:

When we remember events, we often also remember what we were feeling at the time. Cambiaghi et al. asked where in the brain we store such connections. To answer this, they conditioned rats to associate a tone with an unpleasant experience. They then simultaneously recorded from two brain regions, the higher-order auditory cortex and the amygdala, 1 day and 1 month after the conditioning. Animals displayed fearful behavior at both time points, and both areas showed learning-evoked changes. However, the two brain regions only interacted significantly after 1 month had passed (The cue increased the synchrony of their firing.) The degree of interaction predicted the animals' ability to recognize the tone as unpleasant.

Screenagers - brain executive function immediately diminished by television

An article by Jolly points to interesting work by Lillard and Peterson. Their summary:

The goal of this research was to study whether a fast-paced television show immediately influences preschool-aged children's executive function (eg, self-regulation, working memory).  Sixty 4-year-olds were randomly assigned to watch a fast-paced television cartoon or an educational cartoon or draw for 9 minutes. They were then given 4 tasks tapping executive function, including the classic delay-of-gratification and Tower of Hanoi tasks. Parents completed surveys regarding television viewing and child's attention. Children who watched the fast-paced television cartoon performed significantly worse on the executive function tasks than children in the other 2 groups when controlling for child attention, age, and television exposure.  Just 9 minutes of viewing a fast-paced television cartoon had immediate negative effects on 4-year-olds' executive function. Parents should be aware that fast-paced television shows could at least temporarily impair young children's executive function.

Our progression towards a nation of rich and poor

A fascinating and foreboding piece by Rank and Hirschl describe their development of a "economic risk calculator' available at riskcalculator.org

The idea behind our approach is similar to the idea behind a doctor’s ability to predict your risk of heart disease. Using several pieces of information (blood pressure, cholesterol, etc.), your doctor can make a reasonable estimate of your chances of having a heart attack in the next 10 years. These numbers are based on statistical patterns derived from a very large sample of families that make up the Framingham Heart Study, the longitudinal study of cardiovascular health that began in 1948.

Our predictions of economic risk work in a similar way. Using hundreds of thousands of case records taken from a longitudinal study of Americans that began in 1968, we estimate the likelihood — based on factors like race, education, marital status and age — of an individual’s falling below the official poverty line during the next five, 10 or 15 years. (The poverty line for a family of four in 2015 was approximately $24,000.)

Take someone ... who is in his or her later 30s, white, not married, with an education beyond high school. It turns out that the 15-year risk of poverty for such a person is actually 32 percent. In other words, one-third of such individuals will experience at least one year below the poverty line in the not-so-distant future...between the ages of 20 and 75, nearly 60 percent of Americans will spend at least one year below the official poverty line, and three-quarters will experience a year below 150 percent of the poverty line.

We are in danger of becoming an economically polarized society in which a small percentage of the population is free from economic risk, while a vast majority of Americans will encounter poverty as a normal part of life.

Suppressing memory of trauma causes forgetting of other memories.

An interesting article from Hulbert et.al. on how suppressing memory of a trauma also causes forgetting of unrelated experiences in the period surrounding the trauma.:

Hippocampal damage profoundly disrupts the ability to store new memories of life events. Amnesic windows might also occur in healthy people due to disturbed hippocampal function arising during mental processes that systemically reduce hippocampal activity. Intentionally suppressing memory retrieval (retrieval stopping) reduces hippocampal activity via control mechanisms mediated by the lateral prefrontal cortex. Here we show that when people suppress retrieval given a reminder of an unwanted memory, they are considerably more likely to forget unrelated experiences from periods surrounding suppression. This amnesic shadow follows a dose-response function, becomes more pronounced after practice suppressing retrieval, exhibits characteristics indicating disturbed hippocampal function, and is predicted by reduced hippocampal activity. These findings indicate that stopping retrieval engages a suppression mechanism that broadly compromises hippocampal processes and that hippocampal stabilization processes can be interrupted strategically. Cognitively triggered amnesia constitutes an unrecognized forgetting process that may account for otherwise unexplained memory lapses following trauma.

Vasopressin increases human risky cooperative behavior

From Brunnlieb et al.:

Significance

Most forms of cooperative behavior take place in a mutually beneficial context where cooperation is risky as its success depends on unknown actions of others. In two pharmacological experiments, we show that intranasal administration of arginine vasopressin (AVP), a hormone that regulates mammalian social behaviors such as monogamy and aggression, increases humans’ tendency to engage in mutually beneficial cooperation. Several control tasks ruled out that AVP’s effects were driven by increased willingness to bare risks in the absence of social context, beliefs about the actions of one’s partner, or altruistic concerns. Our findings provide novel causal evidence for a biological factor underlying cooperation and are in accord with previous findings that cooperation is intrinsically rewarding for humans.

Abstract

The history of humankind is an epic of cooperation, which is ubiquitous across societies and increasing in scale. Much human cooperation occurs where it is risky to cooperate for mutual benefit because successful cooperation depends on a sufficient level of cooperation by others. Here we show that arginine vasopressin (AVP), a neuropeptide that mediates complex mammalian social behaviors such as pair bonding, social recognition and aggression causally increases humans’ willingness to engage in risky, mutually beneficial cooperation. In two double-blind experiments, male participants received either AVP or placebo intranasally and made decisions with financial consequences in the “Stag hunt” cooperation game. AVP increases humans’ willingness to cooperate. That increase is not due to an increase in the general willingness to bear risks or to altruistically help others. Using functional brain imaging, we show that, when subjects make the risky Stag choice, AVP down-regulates the BOLD signal in the left dorsolateral prefrontal cortex (dlPFC), a risk-integration region, and increases the left dlPFC functional connectivity with the ventral pallidum, an AVP receptor-rich region previously associated with AVP-mediated social reward processing in mammals. These findings show a previously unidentified causal role for AVP in social approach behavior in humans, as established by animal research.

Pictures of green spaces make you happier.

Reynolds points to work by van den Berg et al. showing that viewing pictures of green versus built urban areas enhances parasympathetic nervous system activity that is calming and restorative. This results are consonant with those obtained by a Stanford study on the effects of a brief nature experience on rumination, and also with discussions of "blue mind" (cf. calming effect of blue water) versus "red mind."

This laboratory study explored buffering and recovery effects of viewing urban green and built spaces on autonomic nervous system activity. Forty-six students viewed photos of green and built spaces immediately following, and preceding acute stress induction. Simultaneously recorded electrocardiogram and impedance cardiogram signal was used to derive respiratory sinus arrhythmia (RSA) and pre-ejection period (PEP), indicators of respectively parasympathetic and sympathetic activity. The findings provide support for greater recovery after viewing green scenes, as marked by a stronger increase in RSA as a marker of parasympathetic activity. There were no indications for greater recovery after viewing green scenes in PEP as a marker of sympathetic activity, and there were also no indications of greater buffering effects of green space in neither RSA nor PEP. Overall, our findings are consistent with a predominant role of the parasympathetic nervous system in restorative effects of viewing green space.

Rachmaninoff Morceaux de fantasie Op. 3, No. 4, Polichinelle

This is the last of the pieces from my recent recitals that I want to pass on to readers - a robust beginning for a Monday morning!

Anxiety suppresses prefrontal cortex decision ability.

Interesting work from Park et al.:

A debilitating aspect of anxiety is its impact on decision making and flexible control of behavior. These cognitive constructs depend on proper functioning of the prefrontal cortex (PFC). Understanding how anxiety affects PFC encoding of cognitive events is of great clinical and evolutionary significance. Using a clinically valid experimental model, we find that, under anxiety, decision making may be skewed by salient and conflicting environmental stimuli at the expense of flexible top-down guided choices. We also find that anxiety suppresses spontaneous activity of PFC neurons, and weakens encoding of task rules by dorsomedial PFC neurons. These data provide a neuronal encoding scheme for how anxiety disengages PFC during decision making.

Impatience, aging, and leukocyte telomere length.

Yim et al. note in young college volunteers a correlation between a chemical marker of biological aging (leukocyte telomere length, abbr. LTL) and impatience (delay discounting). The wording of the abstract flirts with conflating correlations with causes, and directions of implied causes is not clear - does impatience causes cellular aging or does cellular aging cause impatience?  People with shorter telomeres might be more impatient because they are not going to be around as long?   (Or, do we have  a correlation as spurious as that noted between mortgage loan rates and sunspot frequency in the 1950's? Let the reader decide... ).

Significance

This paper makes a singular contribution to understanding the association between biological aging indexed by leukocyte telomeres length (LTL) and delay discounting measured in an incentivized behavioral economic task. In a large group of young, healthy undergraduates, steeper delay discounting is significantly associated with shorter LTL, while controlling for risk attitude and health-related behaviors. Notably, we found that delay discounting and risk attitude—two fundamental determinants of economic preferences—are independently associated with LTL. Moreover, for the first time to our knowledge, the effects of well-studied oxytocin and estrogen receptor polymorphisms are shown to specifically moderate the impact of impatience on LTL. Our work suggests a path to integrate behavioral economic methodology to supposed biological mechanisms associated with health outcomes. 

Abstract 

In a graying world, there is an increasing interest in correlates of aging, especially those found in early life. Leukocyte telomere length (LTL) is an emerging marker of aging at the cellular level, but little is known regarding its link with poor decision making that often entails being overly impatient. Here we investigate the relationship between LTL and the degree of impatience, which is measured in the laboratory using an incentivized delay discounting task. In a sample of 1,158 Han Chinese undergraduates, we observe that steeper delay discounting, indexing higher degree of impatience, is negatively associated with LTL. The relationship is robust after controlling for health-related variables, as well as risk attitude—another important determinant of decision making. LTL in females is more sensitive to impatience than in males. We then asked if genes possibly modulate the effect of impatient behavior on LTL. The oxytocin receptor gene (OXTR) polymorphism rs53576, which has figured prominently in investigations of social cognition and psychological resources, and the estrogen receptor β gene (ESR2) polymorphism rs2978381, one of two gonadal sex hormone genes, significantly mitigate the negative effect of impatience on cellular aging in females. The current results contribute to understanding the relationship between preferences in decision making, particularly impatience, and cellular aging, for the first time to our knowledge. Notably, oxytocin and estrogen receptor polymorphisms temper accelerated cellular aging in young females who tend to make impatient choices.

Political Substance Abuse: Donald Trump in Florida

I have to pass this on.

Seasonality in human cognitive brain responses

A brief review in PNAS points to an article by Meyer et.al.:

Mood changes have been linked to seasonality, but little is known about how other human brain functions may vary according to the seasons. Christelle Meyer et al. measured the cognitive brain function of 28 volunteers at different times of the year. For each testing period, each participant spent 5 days in the laboratory, devoid of seasonal cues, such as daylight, and without access to the external world. At the end of the 5-day period, the authors used functional MRI to assess sustained attention and higher executive function in two separate tasks. Performance on both tasks remained constant, but the brain resources used to complete each task changed with the seasons. Brain activity related to sustained attention peaked in June near the summer solstice and was lowest near the winter solstice. In contrast, working memory-related brain activity, a higher-order task, peaked in fall and was lower near the spring equinox. The authors report that these results did not correlate with endocrine measures, such as melatonin, or neurophysiological measures of alertness and sleep. According to the authors, in addition to daily circadian rhythms, certain brain functions may be more seasonal than previously appreciated and that seasonal rhythmicity may be specific to the cognitive process.

Seasonal variations in brain responses to two cognitive tasks, where the black lines represent the mean values.

Rachmaninoff Morceaux de fantasie Op. 3 No. 1 Elegie

I continue to pass on a few of the pieces done at my recent piano recitals.

 

Our brains remember the good stuff.

Anderson et al. show how our brains are attracted to items that have pleased us in the past, even if they are no longer relevant. People in a study were asked to look at a computer screen filled with colored objects and find the red and green ones, They received a small amount of money for each red or green object found. On the next day, the subjects were asked to find certain shapes on the screen, the color being irrelevant. Even so, when a red object appeared it captured attention, and PET brain imaging showed dopamine release in the ventral striatum, which plays a role in reward learning. Here is their technical abstract:

Highlights
•We examined the neural correlates of value-based attention using PET
•Previously reward-associated stimuli involuntary captured attention as distractors
•Such attentional capture was predicted by dopamine release in the dorsal striatum
•Our findings elucidate the neurochemical basis of value-based distraction

Summary
Reward learning gives rise to strong attentional biases. Stimuli previously associated with reward automatically capture visual attention regardless of intention. Dopamine signaling within the ventral striatum plays an important role in reward learning, representing the expected reward initiated by a cue. How dopamine and the striatum may be involved in maintaining behaviors that have been shaped by reward learning, even after reward expectancies have changed, is less well understood. Nonspecific measures of brain activity have implicated the striatum in value-based attention. However, the neurochemical mechanisms underlying the attentional priority of learned reward cues remain unexplored. Here, we investigated the contribution of dopamine to value-based attention using positron emission tomography (PET) with [11C]raclopride. We show that, in the explicit absence of reward, the magnitude of attentional capture by previously reward-associated but currently task-irrelevant distractors is correlated across individuals with changes in available D2/D3 dopamine receptors (presumably due to intrasynaptic dopamine) linked to distractor processing within the right caudate and posterior putamen. Our findings provide direct evidence linking dopamine signaling within the striatum to the involuntary orienting of attention, and specifically to the attention-grabbing quality of learned reward cues. These findings also shed light on the neurochemical basis of individual susceptibility to value-driven attentional capture, which is known to play a role in addiction. More broadly, the present study highlights the value and feasibility of using PET to relate changes in the release of a neurotransmitter to learning-dependent changes in healthy adults.

Brain games and driving safely.

I've done a number of posts on brain games (cf. here, here, and here) and their critics. When I overcome my lassitude and occasionally return to dink with one of the BrainHQ games, I am struck by at least temporary improvements in the cognitive activity being refined, particularly with the vision exercises dealing with useful field of view, contrast sensitivity, etc. The exercise called Double Decision seems to me especially effective. I notice an effect on my driving after playing it. I thought I would pass on this BrainHQ web page on research on BrainHQ exercises. Their claim is that the studies have shown that after training, drivers on average:

-Make 38% fewer dangerous driving maneuvers
-Can stop 22 feet sooner when driving 55 miles per hour
-Feel more confident driving in difficult conditions (such as at night, in bad weather, or in new places)
-Cut their at-fault crash risk by 48%
-Keep their license later in life

Wearing a bike helmet increases risk taking.

From Gamble and Walker:

Humans adapt their risk-taking behavior on the basis of perceptions of safety; this risk-compensation phenomenon is typified by people taking increased risks when using protective equipment. Existing studies have looked at people who know they are using safety equipment and have specifically focused on changes in behaviors for which that equipment might reduce risk. Here, we demonstrated that risk taking increases in people who are not explicitly aware they are wearing protective equipment; furthermore, this happens for behaviors that could not be made safer by that equipment. In a controlled study in which a helmet, compared with a baseball cap, was used as the head mount for an eye tracker, participants scored significantly higher on laboratory measures of both risk taking and sensation seeking. This happened despite there being no risk for the helmet to ameliorate and despite it being introduced purely as an eye tracker. The results suggest that unconscious activation of safety-related concepts primes globally increased risk propensity.

Brahms Waltzes Op. 39, Nos. 1,13,14

Recorded on my Steinway B, now in my Fort Lauderdale condo. I did this piece in recitals in Madison WI and Fort Lauderdale in the past 6 months, and now have made a good quality video recording for my youtube channel. I plan to do this with several of the pieces played at the recitals.


The first of the waltzes has a very robust opening that always brings back memories of my listening to a Saturday morning radio program produced by KTBC in Austin Texas, that invited students taking music lessons to perform a piece, which I dutifully did when I was 12. The program’s opening music was the first of these Brahms waltzes, and I couldn’t imagine ever being able to play something that sounded so difficult.

Stephen Wolfram on A.I. and the future of civilization

Some clips from a Wolfram discussion (well worth reading) that notes the limits of doing things with machines...

The machine is able to execute things, but something or someone has to define what its goals should be and what it's trying to execute.

What makes us different from all these things? What makes us different is the particulars of our history, which gives us our notions of purpose and goals. That's a long way of saying when we have the box on the desk that thinks as well as any brain does, the thing it doesn't have, intrinsically, is the goals and purposes that we have. Those are defined by our particulars—our particular biology, our particular psychology, our particular cultural history.

The thing we have to think about as we think about the future of these things is the goals. That's what humans contribute, that's what our civilization contributes—execution of those goals; that's what we can increasingly automate. We've been automating it for thousands of years. We will succeed in having very good automation of those goals. I've spent some significant part of my life building technology to essentially go from a human concept of a goal to something that gets done in the world.

Repeated social defeat causes neuroinflammation and memory impairment.

I pass on the significance statement from McKim et al., the link gives the more technical abstract.

Repeated exposure to stress alters the homeostatic environment of the brain, giving rise to various cognitive and mood disorders that impair everyday functioning and overall quality of life. The brain, previously thought of as an immune-privileged organ, is now known to communicate extensively with the peripheral immune system. This brain–body communication plays a significant role in various stress-induced inflammatory conditions, also characterized by psychological impairments. Findings from this study implicate neuroimmune activation rather than impaired neurogenesis in stress-induced cognitive deficits. This idea opens up possibilities for novel immune interventions in the treatment of cognitive and mood disturbances, while also adding to the complexity surrounding the functional implications of adult neurogenesis.

Punishment of others: decreased by status in the West, increased in the East

An interesting commentary from Kuwabara et al.:

In the experiments reported here, we integrated work on hierarchy, culture, and the enforcement of group cooperation by examining patterns of punishment. Studies in Western contexts have shown that having high status can temper acts of dominance, suggesting that high status may decrease punishment by the powerful. We predicted that high status would have the opposite effect in Asian cultures because vertical collectivism permits the use of dominance to reinforce the existing hierarchical order. Across two experiments, having high status decreased punishment by American participants but increased punishment by Chinese and Indian participants. Moreover, within each culture, the effect of status on punishment was mediated by feelings of being respected. A final experiment found differential effects of status on punishment imposed by Asian Americans depending on whether their Asian or American identity was activated. Analyzing enforcement through the lens of hierarchy and culture adds insight into the vexing puzzle of when and why people engage in punishment.

More on clever crows - they learn shell games.

Chopin Trois Eccossaises

Recorded on my Steinway B, now in my Fort Lauderdale condo. I did this piece in recitals in Madison WI and Fort Lauderdale in the past 6 months, and now have made a good quality video recording for my youtube channel. I plan to do this with several of the pieces played at the recitals.

New nerve cells in the brain generated best by sustained aerobic exercise

Nokia et al. show, in rats, that aerobic exercise is much more effective than high-intensity interval training or resistance training in enhancing generation of new nerve cells in the hippocampus of the brain.

Key points

Aerobic exercise such as running enhances adult hippocampal neurogenesis (AHN) in rodents. 

Little is known about the effects of high-intensity interval training (HIT) or of purely anaerobic resistance training on AHN. 

Here, compared to a sedentary lifestyle, we report a very modest effect of HIT and no effect of resistance training on AHN in adult male rats. 

We find most AHN in rats that were selectively bred for an innately high response to aerobic exercise that also run voluntarily and - increase maximum running capacity. 

Our results confirm that sustained aerobic exercise is key in improving AHN.

Abstract

Aerobic exercise, such as running, has positive effects on brain structure and function, for example, adult hippocampal neurogenesis (AHN) and learning. Whether high-intensity interval training (HIT), referring to alternating short bouts of very intense anaerobic exercise with recovery periods, or anaerobic resistance training (RT) has similar effects on AHN is unclear. In addition, individual genetic variation in the overall response to physical exercise likely plays a part in the effects of exercise on AHN but is less studied. Recently, we developed polygenic rat models that gain differentially for running capacity in response to aerobic treadmill training. Here we subjected these Low Response Trainer (LRT) and High Response Trainer (HRT) adult male rats to various forms of physical exercise for 6 to 8 weeks and examined its effects on AHN. Compared to sedentary animals, the highest number of doublecortin-positive hippocampal cells was observed in HRT rats that ran voluntarily on a running wheel while HIT on the treadmill had a smaller, statistically non-significant effect on AHN. AHN was elevated in both LRT and HRT rats that endurance trained on a treadmill compared to those that performed RT by climbing a vertical ladder with weights, despite their significant gain in strength. Furthermore, RT had no effect on proliferation (Ki67), maturation (doublecortin) or survival (BrdU) of new adult-born hippocampal neurons in adult male Sprague-Dawley rats. Our results suggest physical exercise promotes AHN most if it is aerobic and sustained, and especially when accompanied by a heightened genetic predisposition for response to physical exercise.

This is too good not to pass on.....

If all the world's a stage, do we have a true self?

My reading of Irving Goffman's classic "The Presentation of the Self in Everyday Life" in the early 1970's was the beginning of my going beyond my laboratory research on the molecules of vision to start a parallel line of study and reading on how our minds work (see dericbownds.net). I recently came across this engaging very brief video on Goffman's ideas, narrated by Stephen Fry, and thought I would pass it on. (This is one of the items from the BBC's excellent "A History of Ideas" series.)

"Well-being" as a practiced skill

I thought I would pass on from the mindful.org website yet another piece featuring my Wisconsin colleague Richie Davidson, noting his presentation on "Four Constituents of Well-Being," namely:

Resilience - rapid recovery from shit happening
Outlook -savoring positive, seeing good in people
Attention - a wandering mind is an unhappy mind
Generosity - kindness to oneself and others

The article has numerous links to research on good stuff which offers a temporary relief from the dystopian input of our entertainment and news overlords.

Getting rid of old cells extends lifespan of mice and ameliorates age-related diseases.

Baker et al. show that getting rid of cells that have entered an irreversible senescent state expands the lifespan of mice and ameliorates some age-related disease processes. Clips from the Gil and Withers summary of the work:

More than 50 years ago, it was suggested that ageing is linked to a state of arrested cell growth known as senescence, but this link has remained unproven, and the molecular basis for organismal ageing has been elusive...Senescence is a cellular state in which cells permanently stop dividing. It is mediated by two signalling pathways — the p53 pathway and the p16Ink4a–Rb pathway. Senescent cells secrete a complex cocktail of factors called the senescence-associated secretory phenotype (SASP), which includes matrix metalloproteinases (enzymes that break down the extracellular matrix) and pro-inflammatory signalling molecules. Such cells have been shown to accumulate during ageing, and their presence has been associated with a broad range of diseases, including diabetes, kidney disease and many cancers.

Baker et al. demonstrate that the removal of senescent cells does indeed delay ageing and increase healthy lifespan (healthspan)...using a genetically engineered mouse model that they had developed previously4, called INK–ATTAC. These mice produce a caspase enzyme specifically in cells that express the p16Ink4a gene. The caspase can be activated by the injection of a drug; the activated caspase then triggers cell death, eliminating senescent cells in which it is expressed...[They] found that the elimination of p16Ink4a-expressing cells increased lifespan, regardless of the sex or strain of mouse examined, and ameliorated a range of age-dependent, disease-related abnormalities, including kidney dysfunction and abnormalities in heart and fat tissue.

A brain circuit for loneliness.

Tye and colleagues find a neural circuit at the base of mouse brains that drives loneliness-like behaviors and drives the animals to seek company. From a review:

...connections between neurons in the circuit were stronger in mice that were separated from their cage mates than in those that were grouped together. Those neurons then fired more frequently when isolated mice were put in a cage with an unfamiliar mouse, compared with animals that had not been isolated. When the scientists inhibited the neurons with light, the isolated mice showed less interest in the stranger. Activating those neurons caused the animals to actively seek other mice.

Here is the abstract for the work:

Highlights

•Dorsal raphe nucleus (DRN) dopamine neurons are sensitive to acute social isolation 

•DRN dopamine neurons release dopamine and glutamate in downstream structures 

•Optical activation induces, whereas inhibition suppresses, a “loneliness-like” state 

•Social rank predicts the behavioral effect induced by optical manipulations

Summary

The motivation to seek social contact may arise from either positive or negative emotional states, as social interaction can be rewarding and social isolation can be aversive. While ventral tegmental area (VTA) dopamine (DA) neurons may mediate social reward, a cellular substrate for the negative affective state of loneliness has remained elusive. Here, we identify a functional role for DA neurons in the dorsal raphe nucleus (DRN), in which we observe synaptic changes following acute social isolation. DRN DA neurons show increased activity upon social contact following isolation, revealed by in vivo calcium imaging. Optogenetic activation of DRN DA neurons increases social preference but causes place avoidance. Furthermore, these neurons are necessary for promoting rebound sociability following an acute period of isolation. Finally, the degree to which these neurons modulate behavior is predicted by social rank, together supporting a role for DRN dopamine neurons in mediating a loneliness-like state.