Do you have a tidy or messy desk?

Vohs et al. have done an interesting experiment that suggests that physical order enhances healthy choices, generosity, and conventionality, while disorder correlates with greater creativity. I don't go with their "novel hypothesis" description, but the results describe my partner and myself rather well (I'm the tidy one). The abstract:

Order and disorder are prevalent in both nature and culture, which suggests that each environ confers advantages for different outcomes. Three experiments tested the novel hypotheses that orderly environments lead people toward tradition and convention, whereas disorderly environments encourage breaking with tradition and convention—and that both settings can alter preferences, choice, and behavior. A first experiment showed that relative to participants in a disorderly room, participants in an orderly room chose healthier snacks and donated more money. A second experiment showed that participants in a disorderly room were more creative than participants in an orderly room. A final experiment showed a predicted crossover effect: Participants in an orderly room preferred an option labeled as classic, but those in a disorderly room preferred an option labeled as new. Whereas prior research on physical settings has shown that orderly settings encourage better behavior than disorderly ones, the current research tells a nuanced story of how different environments suit different outcomes.

Clips from the text:

Being in a clean room seemed to encourage people to do what was expected of them. Compared with participants in the messy room, they donated more of their own money to charity and were more likely to choose the apple over the candy bar....Being in a messy room led to something that firms, industries, and societies want more of: Creativity...Orderly environments promote convention and healthy choices, which could improve life by helping people follow social norms and boosting well-being. Disorderly environments stimulated creativity, which has widespread importance for culture, business, and the arts.

Imperceptible current applied to our scalp enhances general intelligence.

Here is yet another of the increasing number of articles examining the effects of very weak electrical stimulation of our frontal scalp with surface electrodes. I've done a number of posts on this topic, the most recent citing concerns over do it yourself kits now available to anyone. Santarnecchi et al. address the frequency-specific effect of stimulation with the main physiological brain rhythms by comparing performance during four tACS (transcranial alternating current stimulation) conditions — 5 Hz (θ band), 10 Hz (α band), 20 Hz (β band), and 40 Hz (γ band) — and a placebo, sham stimulation. Their summary:

-Online prefrontal γ-tACS selectively accelerated logical reasoning.

-Effects were frequency and task specific

-This contrasts with views of gamma-band activity as a byproduct of neuronal activity

-Gamma-band activity plays a functional role in fluid-intelligence-based reasoning

Everyday problem solving requires the ability to go beyond experience by efficiently encoding and manipulating new information, i.e., fluid intelligence (Gf). Performance in tasks involving Gf, such as logical and abstract reasoning, has been shown to rely on distributed neural networks, with a crucial role played by prefrontal regions. Synchronization of neuronal activity in the gamma band is a ubiquitous phenomenon within the brain; however, no evidence of its causal involvement in cognition exists to date. Here, we show an enhancement of Gf ability in a cognitive task induced by exogenous rhythmic stimulation within the gamma band. Imperceptible alternating current delivered through the scalp over the left middle frontal gyrus resulted in a frequency-specific shortening of the time required to find the correct solution in a visuospatial abstract reasoning task classically employed to measure Gf abilities (i.e., Raven’s matrices). Crucially, gamma-band stimulation (γ-tACS) selectively enhanced performance only on more complex trials involving conditional/logical reasoning. The present finding supports a direct involvement of gamma oscillatory activity in the mechanisms underlying higher-order human cognition.

Left Middle Frontal Gyrus

Evidence that the Lunar cycle influences human sleep.

I have kept a log for many years that has convinced me that I have roughly monthly oscillations in motivation and libido, but I've not come across convincing evidence for roughly lunar or monthly cycles in men in literature searches. So, I perk up on seeing the examination by Cajochen et al. of sleep behavior under highly controlled conditions of a circadian laboratory study protocol without time cues. They find that subjective and objective measures of sleep vary according to lunar periodicity (~29.5 days). Subjects in the study were seventeen healthy young volunteers (nine women and eight men; age range, 20–31 years; mean, 25.0 ± 3.6 years [SD]) and 16 healthy older volunteers (eight women and eight men; age range, 57–74 years; mean, 65.0 ± 5.5 years) Here is their abstract:

Endogenous rhythms of circalunar periodicity (∼29.5 days) and their underlying molecular and genetic basis have been demonstrated in a number of marine species. In contrast, there is a great deal of folklore but no consistent association of moon cycles with human physiology and behavior. Here we show that subjective and objective measures of sleep vary according to lunar phase and thus may reflect circalunar rhythmicity in humans. To exclude confounders such as increased light at night or the potential bias in perception regarding a lunar influence on sleep, we retrospectively analyzed sleep structure, electroencephalographic activity during non-rapid-eye-movement (NREM) sleep, and secretion of the hormones melatonin and cortisol found under stringently controlled laboratory conditions in a cross-sectional setting. At no point during and after the study were volunteers or investigators aware of the a posteriori analysis relative to lunar phase. We found that around full moon, electroencephalogram (EEG) delta activity during NREM sleep, an indicator of deep sleep, decreased by 30%, time to fall asleep increased by 5 min, and EEG-assessed total sleep duration was reduced by 20 min. These changes were associated with a decrease in subjective sleep quality and diminished endogenous melatonin levels. This is the first reliable evidence that a lunar rhythm can modulate sleep structure in humans when measured under the highly controlled conditions of a circadian laboratory study protocol without time cues.

 

Personal control enhances treatment effectiveness.

An interesting fragment, relating to the powerful vs helplessness theme of a recent post, subjects faced with alternative pain control drugs (both actually placebos) reported better pain relief if they chose the drug rather than having it chosen for them. From Geers et al.:

In modern health care, individuals frequently exercise choice over health treatment alternatives. A growing body of research suggests that when individuals choose between treatment options, treatment effectiveness can increase, although little experimental evidence exists clarifying this effect. Four studies were conducted to test the hypothesis that exercising choice over treatment alternatives enhances outcomes by providing greater personal control. Consistent with this possibility, in Study 1 individuals who chronically desired control reported less pain from a laboratory pain task when they were able to select between placebo analgesic treatments. Study 2 replicated this finding with an auditory discomfort paradigm. In Study 3, the desire for control was experimentally induced, and participants with high desire for control benefited more from a placebo treatment when they were able to choose their treatment. Study 4 revealed that the benefit of choice on treatment efficacy was partially mediated by thoughts of personal control. This research suggests that when individuals desire control, choice over treatment alternatives improves treatment effectiveness by enhancing personal control.

Think your radiologist gets it right? The invisible gorilla strikes again.

A well known video shows the famous experiment of missing a gorilla walking through a basketball game when you have been instructed to count the number of times the ball is being passed during playing. (I can not refer you to a free viewing of this video, since the academic who originated it, Dan Simons, has copyrighted it, and aggressively pursues those who might wish to watch it without paying him for a DVD that contain it.) Anyway, an extension of his basic experiment gives you reason to feel even less confident about the expertise of high priced radiologists examining your X-rays. This from Drew et al.:

Researchers have shown that people often miss the occurrence of an unexpected yet salient event if they are engaged in a different task, a phenomenon known as inattentional blindness. However, demonstrations of inattentional blindness have typically involved naive observers engaged in an unfamiliar task. What about expert searchers who have spent years honing their ability to detect small abnormalities in specific types of images? We asked 24 radiologists to perform a familiar lung-nodule detection task. A gorilla, 48 times the size of the average nodule, was inserted in the last case that was presented. Eighty-three percent of the radiologists did not see the gorilla. Eye tracking revealed that the majority of those who missed the gorilla looked directly at its location. Thus, even expert searchers, operating in their domain of expertise, are vulnerable to inattentional blindness.

Degree of Musical Expertise Modulates Higher Order Brain Functioning

A piece like this one by Oechslin et al. gives me some hope that my piano playing and sight reading compensate for my aversion to spending any significant amount of time on anti-aging brain exercise regimes of the sort described in a recent post. Hopefully, if I keep up my piano playing as I age, I will be going ga-ga later rather than sooner. The abstract:

Using functional magnetic resonance imaging, we show for the first time that levels of musical expertise stepwise modulate higher order brain functioning. This suggests that degree of training intensity drives such cerebral plasticity. Participants (non-musicians, amateurs, and expert musicians) listened to a comprehensive set of specifically composed string quartets with hierarchically manipulated endings. In particular, we implemented 2 irregularities at musical closure that differed in salience but were both within the tonality of the piece (in-key). Behavioral sensitivity scores (d′) of both transgressions perfectly separated participants according to their level of musical expertise. By contrasting brain responses to harmonic transgressions against regular endings, functional brain imaging data showed compelling evidence for stepwise modulation of brain responses by both violation strength and expertise level in a fronto-temporal network hosting universal functions of working memory and attention. Additional independent testing evidenced an advantage in visual working memory for the professionals, which could be predicted by musical training intensity. The here introduced findings of brain plasticity demonstrate the progressive impact of musical training on cognitive brain functions that may manifest well beyond the field of music processing.

Be young in perception and behavior! Put yourself in a virtual child’s body!

Banakou et al. show that if we use some simple tricks to project ourselves into a 4-year old's body, we overestimate object sizes and more readily associate ourselves with child-like attributes:

An illusory sensation of ownership over a surrogate limb or whole body can be induced through specific forms of multisensory stimulation, such as synchronous visuotactile tapping on the hidden real and visible rubber hand in the rubber hand illusion. Such methods have been used to induce ownership over a manikin and a virtual body that substitute the real body, as seen from first-person perspective, through a head-mounted display. However, the perceptual and behavioral consequences of such transformed body ownership have hardly been explored. In the first experiment, immersive virtual reality was used to embody 30 adults as a 4-y-old child (condition C), and as an adult body scaled to the same height as the child (condition A), experienced from the first-person perspective, and with virtual and real body movements synchronized. The result was a strong body-ownership illusion equally for C and A. Moreover there was an overestimation of the sizes of objects compared with a nonembodied baseline, which was significantly greater for C compared with A. An implicit association test showed that C resulted in significantly faster reaction times for the classification of self with child-like compared with adult-like attributes. A second experiment with an additional 16 participants extinguished the ownership illusion by using visuomotor asynchrony, with all else equal. The size-estimation and implicit association test differences between C and A were also extinguished. We conclude that there are perceptual and probably behavioral correlates of body-ownership illusions that occur as a function of the type of body in which embodiment occurs.

Experimental setup. The body of the participant was substituted by a sex-matched virtual body, viewed from first-person perspective, onto which body and head movements were mapped in real time. The body could also be seen as reflected in a virtual mirror as shown. The body each participant viewed depended on the condition C (for child) or A (for adult) to which each one was assigned. (A) A female participant in a child’s body. (B) A female participant in a scaled-down adult’s body. (C) Participants’ body movements were tracked by 34 Optitrack markers.

The bad kind of stress - perceived helplessness

Velasquez-Manoff does a nice discussion of a topic that has been recurrent in MindBlog, understanding the kind of stress that is really bad for us. Not the stress that goes with daily personal and professional aggravations, but the long term stress that derives from feeling helpless to control our lives. Numerous studies, the best known being a long term study of British civil servants, have shown that being higher in a social hierarchy correlates with having better health. The sense of control:

...tends to decline as one descends the socioeconomic ladder, with potentially grave consequences. Those on the bottom are more than three times as likely to die prematurely as those at the top. They’re also more likely to suffer from depression, heart disease and diabetes. Perhaps most devastating, the stress of poverty early in life can have consequences that last into adulthood.

The article quotes Robert Sapolsky at Stanford, whose classic book "Why Zebras Don't Get Ulcers" is still a must read, as saying:

Early-life stress and the scar tissue that it leaves, with every passing bit of aging, gets harder and harder to reverse...You’re never out of luck in terms of interventions, but the longer you wait, the more work you’ve got on your hands.

Bruce McEwen and others talk about

...the “biological embedding” of social status. Your parents’ social standing and your stress level during early life change how your brain and body work, affecting your vulnerability to degenerative disease decades later. They may even alter your vulnerability to infection. In one study, scientists at Carnegie Mellon exposed volunteers to a common cold virus. Those who’d grown up poorer (measured by parental homeownership) not only resisted the virus less effectively, but also suffered more severe cold symptoms.

Another clip:

Animal studies help dispel doubts that we’re really seeing sickly and anxiety-prone individuals filter to the bottom of the socioeconomic heap. In primate experiments females of low standing are more likely to develop heart disease compared with their counterparts of higher standing. When eating junk food, they more rapidly progress toward heart disease. The lower a macaque is in her troop, the higher her genes involved in inflammation are cranked. High-ranking males even heal faster than their lower-ranking counterparts. Behavioral tendencies change as well. Low-ranking males are more likely to choose cocaine over food than higher-ranking individuals.

Finally:

...while Americans generally gained longevity during the late 20th century, those gains have gone disproportionately to the better-off. Those without a high school education haven’t experienced much improvement in life span since the middle of the 20th century. Poorly educated whites have lost a few years of longevity in recent decades.

A National Research Council report, meanwhile, found that Americans were generally sicker and had shorter life spans than people in 16 other wealthy nations. We rank No. 1 for diabetes in adults over age 20, and No. 2 for deaths from coronary artery disease and lung disease. The Japanese smoke more than Americans, but outlive us — as do the French and Germans, who drink more. The dismal ranking is surprising given that America spends nearly twice as much per capita on health care as the next biggest spender.

Different kinds of happiness - different immune system consequences.

Happiness is usually classified into two main flavors: hedonic and eudaimonic. Hedonic refers mainly to self gratification and eudaimonic to a sense of meaning and purpose beyond that. In a study involving 80 healthy adult subjects, Fredrickson et al. used a questionnaire to asses levels of hedonic and eudaimonic happiness (questions such as 'over the last week, how often did you feel happy or satisfied? (hedonic); or, 'how often in the last week did you feel your life has a sense of purpose, meaning or direction?' (eudaimonic). They also looked at expression of genes associated with immune system responses. The fascinating result was that hedonic happiness correlated with higher expression of genes typically activated by extended periods of stress, activity that increases inflammation and decreases antiviral responses. Higher Eudaimonic happiness correlated with lower activation levels of these genes and strengthened immune function.

Both kinds of happiness make us "feel good." The central point is that our genome may be "more sensitive to qualitative variations in well-being than are our conscious affective experiences." Here is their abstract:

To identify molecular mechanisms underlying the prospective health advantages associated with psychological well-being, we analyzed leukocyte basal gene expression profiles in 80 healthy adults who were assessed for hedonic and eudaimonic well-being, as well as potentially confounded negative psychological and behavioral factors. Hedonic and eudaimonic well-being showed similar affective correlates but highly divergent transcriptome profiles. Peripheral blood mononuclear cells from people with high levels of hedonic well-being showed up-regulated expression of a stress-related conserved transcriptional response to adversity (CTRA) involving increased expression of proinflammatory genes and decreased expression of genes involved in antibody synthesis and type I IFN response. In contrast, high levels of eudaimonic well-being were associated with CTRA down-regulation. Promoter-based bioinformatics implicated distinct patterns of transcription factor activity in structuring the observed differences in gene expression associated with eudaimonic well-being (reduced NF-κB and AP-1 signaling and increased IRF and STAT signaling). Transcript origin analysis identified monocytes, plasmacytoid dendritic cells, and B lymphocytes as primary cellular mediators of these dynamics. The finding that hedonic and eudaimonic well-being engage distinct gene regulatory programs despite their similar effects on total well-being and depressive symptoms implies that the human genome may be more sensitive to qualitative variations in well-being than are our conscious affective experiences.

Workouts at the brain gym.

Patricia Marx writes an engaging article in The New Yorker, "Mentally Fit," that describes her foray into various regimes for building cognitive and emotional muscle, to stave off the declines in memory and attention capacity that come with aging, and are accelerated by vascular dementia and Alzheimer's pathology.

Staving off dotage is not cheap. According to a recent report issued by SharBrains, the amount spent on brain fitness in 2012 was more than a billion dollars, and by 2020, it is estimated, that figure will exceed six billion dollars. Most of the merchandise is some kind of software (note: which have been the subject of several MindBlog posts). …. to name just a few: Cogmed, Lumosity, Brain Games, Jungle Memory, Cognifit, MindSparke, MyBrainSolution, Brain Spa, brainTivity, Brainiversity, Brain Metrix, Mind Quiz, Your Brain Coach, Brain Exercise with Dr. Kawashima, Nintendo's Brain Age, MindHabits, NeuroNation, Happyneuron. There seem to be enough products to give each of your synapses its very own person-training program.

The cost of these programs ranges from zero to $1,500. The author chose BrainHQ, a platform offered by Posit Science, a San Francisco company co-founded by respected neuroscientist Michael Merzenich. It's exercises center around making your eyes and attention more childlike and sparky, countering the decay that makes the peripheral vision of a sixty-year-old three-quarters as panoramic as that of a twenty-year-old. After training for an hour a day over six weeks, scores in an array of different exercises were higher across the board. Merznich is probably correct in stating that the observed stronger, faster, more accurate and reliable brain performance after training comes from synaptic remodeling in the brain, a change that he says can persist for a year or more, but that does slips back past the neurological position that you were at when you began the training. (Motivated readers can email me to obtain a PDF of the article.)

Loneliness promotes inflammation in our bodies

Jaremka et al provide further data on how our social status reaches down to the most intimate details of our personal chemistry, with their present study providing details of how loneliness during stress turns on our inflammatory pathways, thus putting us at greater risk for health problems. Here's the abstract:

Although evidence suggests that loneliness may increase risk for health problems, the mechanisms responsible are not well understood. Immune dysregulation is one potential pathway: Elevated proinflammatory cytokines such as interleukin-6 (IL-6) increase risk for health problems. In the first study (N = 134), lonelier healthy adults exposed to acute stress exhibited greater synthesis of tumor necrosis factor-alpha (TNF-α) and IL-6 by peripheral blood mononuclear cells (PBMCs) stimulated with lipopolysaccharide (LPS) than their less lonely counterparts. Similarly, in the second study (N = 144), lonelier posttreatment breast-cancer survivors exposed to acute stress exhibited greater synthesis of IL-6 and interleukin-1 beta (IL-1β) by LPS-stimulated PBMCs than their counterparts who felt more socially connected. However, loneliness was unrelated to TNF-α in the second study, although the result was in the expected direction. Thus, two different populations demonstrated that lonelier participants had more stimulated cytokine production in response to stress than less lonely participants, which reflects a proinflammatory phenotype. These data provide a glimpse into the pathways through which loneliness may affect health.

Markers of our aging

I thought I would point to this interesting piece in the New York Times about the search for some simple objective assay of our biological age, as distinct from our chronological age. We all know people who seems much older or younger than their actual age. Things like skin wrinkles or blood pressure are not a very useful indicator, because they can be confounded by factors unrelated to aging. Reliable biomarkers of aging could:

...tell us a lot about our current and future health. Tracking these indexes before and after starting a new diet or exercise program, for instance, might show you whether it was actually pushing off your decline and fall. Aging-rate tests could help scientists evaluate possible anti-aging compounds in humans without prohibitively long studies.

One study of older women age 65-69 found that 13 factors correlate with healthy aging, including the eye’s ability to pick out very lightly shaded images on white backgrounds, and the number of rapid step-ups on a low platform that subjects could complete in 10 seconds. A more promising approach is finding that a number of chemical tags on our DNA - epigenetic markers, which I have mentioned in previous posts - correlate with our biological age in a way that yields a signature of aging that is not changed by disease or ethnic background.

If this continuing research pans out, aging-rate tests may someday be standard in annual physicals, and tracking the results over time would offer unprecedented insights on health risks. But such tests also may well raise fractious privacy and social equity issues.

Insurers might demand that customers take them in order to set premiums for life and health care policies. The tests may also reveal how factors like exposure to environmental toxins and the stress of job loss accelerate aging, and by how much — fodder for lawsuits.

Some of us will be relatively short-lived, fast-aging “less fortunate,” and others will be long-lived, slow-aging “more fortunates,” predicted John K. Davis, a philosophy professor at California State University, Fullerton. And age discrimination will gain an entirely new meaning.

Unconscious activation of our brains' inhibitory controls.

Hepler and Albarracin have done the interesting experiment of exposing participants in an experiment to subliminally presented inaction (calm) and action (move) words, and then ascertaining that participants were unaware of these primers. They subsequently presented the participants with a Go/No-Go task (press a button if you see an "X", don't press it if you see a "Y") and also measured the P3 component of the event-related brain potential known to index inhibitory control. The subliminally presented inaction (calm) and action (move) words increased inhibitory neural activity whereas the latter set decreased it, relative to a control set of neutral words. Here is the author's summary:

-Event-related potentials were recorded during two go/no-go task with subliminal primes

-Subliminal primes related to general concepts of action, inaction, or were controls.

-Inaction/action primes strengthened/weakened inhibitory control mechanisms (ICMs).

-The primes had never been consciously associated with task responses or goals.

-This is the first demonstration that ICMs can operate completely unconsciously.

Although robust evidence indicates that action initiation can occur unconsciously and unintentionally, the literature on action inhibition suggests that inhibition requires both conscious thought and intentionality. In prior research demonstrating automatic inhibition in response to unconsciously processed stimuli, the unconscious stimuli had previously been consciously associated with an inhibitory response within the context of the experiment, and participants had consciously formed a goal to activate inhibition processes when presented with the stimuli (because task instructions required participants to engage in inhibition when the stimuli occurred). Therefore, prior work suggests that some amount of conscious thought and intentionality are required for inhibitory control. In the present research, we recorded event-related potentials during two go/no-go experiments in which participants were subliminally primed with general action/inaction concepts that had never been consciously associated with task-specific responses. We provide the first demonstration that inhibitory control processes can be modulated completely unconsciously and unintentionally.

Why does time speed up for older people?

I've come across two recent articles recently on how our experience of time is our own invention - "mind time" - that can be faster or slower than clock or calendar time. I find myself incredulous at how fast time seems to pass now compared with my recollection of when I was a 30 or 40-something and felt large periods of leisure in the midst of what was a much more complex (and productive) life than my current retired life (at 71 years of age). In general older people are more likely than younger to report that the last decade has passed quickly. The Friedman piece has a great quote from William James, who argued that the apparent speed of time's passage was a result of adult's experiencing fewer memorable events:

“Each passing year converts some of this experience into automatic routine which we hardly note at all, the days and the weeks smooth themselves out in recollection to contentless units, and the years grow hollow and collapse.”

From Friedman:

Why, then, do older people look back at long stretches of their lives and feel it’s a race to the finish? Here’s a possible answer: think about what it’s like when you learn something for the first time — for example how, when you are young, you learn to ride a bike or navigate your way home from school. It takes time to learn new tasks and to encode them in your memory. And when you are learning about the world for the first time, you are forming a fairly steady stream of new memories of events, places and people.

When, as an adult, you look back at your childhood experiences, they appear to unfold in slow motion probably because the sheer number of them gives you the impression that they must have taken forever to acquire… Most adults do not explore and learn about the world the way they did when they were young; adult life lacks the constant discovery and endless novelty of childhood.

Studies have shown that the greater the cognitive demands of a task, the longer its duration is perceived to be…Is it possible that learning new things might slow down our internal sense of time?…It’s simple: if you want time to slow down, become a student again. Learn something that requires sustained effort; do something novel…Take a new route to work; vacation at an unknown spot. And take your sweet time about it.

The second piece, by Maria Popova article points to Hammond's recent book "Time Warped: Unlocking the Mysteries of Time Perception" and offers a synopsis through multiple quotes, including descriptions of how fear slows down subjective time.

…when people with arachnophobia were asked to look at spiders — the very object of their intense fear — for 45 seconds and they overestimated the elapsed time. The same pattern was observed in novice skydivers, who estimated the duration of their peers’ falls as short, whereas their own, from the same altitude, were deemed longer.

...and the Holiday Paradox

…the contradictory feeling that a good holiday whizzes by, yet feels long when you look back.” (An “American translation” might term it the Vacation Paradox.) Her explanation of its underlying mechanisms is reminiscent of legendary psychologist Daniel Kahneman’s theory of the clash between the “experiencing self” and the “remembering self”….We constantly use both prospective and retrospective estimation to gauge time’s passing. Usually they are in equilibrium, but notable experiences disturb that equilibrium, sometimes dramatically. This is also the reason we never get used to it, and never will. We will continue to perceive time in two ways and continue to be struck by its strangeness every time we go on holiday.

...the difference in the number of novel experiences at different ages:

…we are most likely to vividly remember experiences we had between the ages of 15 and 25. What the social sciences might simply call “nostalgia” psychologists have termed the “reminiscence bump”…The key to the reminiscence bump is novelty. The reason we remember our youth so well is that it is a period where we have more new experiences than in our thirties or forties. It’s a time for firsts — first sexual relationships, first jobs, first travel without parents, first experience of living away from home, the first time we get much real choice over the way we spend our days. Novelty has such a strong impact on memory that even within the bump we remember more from the start of each new experience.

A mechanism of why novelty seeking individuals are more vulnerable to social defeat stress.

Duclot and Kabbaj offer an interesting result that suggests at least part of the reason for why individuals more likely to seek novelty (whether humans or mice) are also more vulnerable to social defeat stress. They do not demonstrate the stress induced increase in levels of a brain growth factor (brain derived neurotrophic factor, or BNDF), that is observed in low novelty seeking individuals. BDNF regulation after stress has been suggested as an important mediator of vulnerability and resilience. Higher BDNF levels in the hippocampus - which can be caused by classic antidepressants - promote resilience to a chronic mild stress. Here is the abstract, with technical details:

Some personality traits, including novelty seeking, are good predictors of vulnerability to stress-related mood disorders in both humans and rodents. While high-novelty-seeking rats [high responders (HRs)] are vulnerable to the induction of depressive-like symptoms by social defeat stress, low-novelty-seeking rats [low responders (LRs)] are not. Here, we show that such individual differences are critically regulated by hippocampal BDNF. While LR animals exhibited an increase in BDNF levels following social defeat, HR individuals did not. This difference in hippocampal BDNF expression promoted the vulnerability of HR and the resilience of LR rats. Indeed, preventing activation of BDNF signaling by infusing the BDNF scavenger TrkB-Fc into the dentate gyrus of the hippocampus of LR rats led to social defeat-induced social avoidance, whereas its activation in HR rats by the TrkB agonist 7,8-dihydroxyflavone promoted social approach. Along with the changes in BDNF expression following defeat, we report in LR animals a downregulation of the inactive BDNF receptor TrkB.T1, associated with an activation of CREB through Akt-mediated signaling, but not MSK1-mediated signaling. In HR animals, none of these molecules were affected by social defeat. Importantly, the BDNF upregulation involved an epigenetically controlled transcription of bdnf exon VI, associated with a coherent regulation of relevant epigenetic factors. Altogether, our data support the importance of hippocampal BDNF regulation in response to stressful events. Moreover, we identify a specific and adaptive regulation of bdnf exon VI in the hippocampus as a critical regulator of stress resilience, and strengthen the importance of epigenetic factors in mediating stress-induced adaptive and maladaptive responses in different individuals.

Positive feedback loop between social connections, positive emotions, and vagal tone.

Kok et al. suggest that positive emotions, positive social connections, and physical health reinforce one another in a positive feedback loop.They use cardiac vagal tone as an objective proxy for physical health. Indexed at rest as variability in heart rate associated with respiratory patterns, vagal tone reflects the functioning of the vagus nerve, which is the 10th cranial nerve and a core component of the parasympathetic nervous system, which regulates heart rate in response to signals of safety and interest. Low vagal tone has been linked to high inflammation, greater risk for myocardial infarction, and lower odds of survival after heart failure.

Their positive feedback loop suggestion sounds good - and is consonant with many recent studies correlating positive emotions, physical health, and longevity - but they do tend to confuse cause and correlation, and do not have appropriate control groups. A 'waiting list control group' really doesn't hack it. A control group should at least have some sort of experimenter engagement with subjects that is as similar as possible to the control group except without the exercises for self-generated positive emotions. Still, the results do show convincing correlations between vagal tone, positive emotions, and social connections in a group that receives training and practices loving kindness meditation for 61 days. Here is the abstract:

The mechanisms underlying the association between positive emotions and physical health remain a mystery. We hypothesize that an upward-spiral dynamic continually reinforces the tie between positive emotions and physical health and that this spiral is mediated by people’s perceptions of their positive social connections. We tested this overarching hypothesis in a longitudinal field experiment in which participants were randomly assigned to an intervention group that self-generated positive emotions via loving-kindness meditation or to a waiting-list control group. Participants in the intervention group increased in positive emotions relative to those in the control group, an effect moderated by baseline vagal tone, a proxy index of physical health. Increased positive emotions, in turn, produced increases in vagal tone, an effect mediated by increased perceptions of social connections. This experimental evidence identifies one mechanism—perceptions of social connections—through which positive emotions build physical health, indexed as vagal tone. Results suggest that positive emotions, positive social connections, and physical health influence one another in a self-sustaining upward-spiral dynamic.

http://pss.sagepub.com/content/24/7/1123.abstract http://pss.sagepub.com.ezproxy.library.wisc.edu/content/24/7/1123.full

Sebastian - The Maestro

Deric and 16 month old grandson Sebastian improvising.

An ancestral logic of politics?

Another evolutionary psychology speculation: If individual dispositions about modern political conflicts are partly generated by evolved mechanisms designed for evolutionarily recurrent conditions, then men with greater upper-body strength should be more likely to adopt political positions that increase their share of resources, whereas men with lesser upper-body strength should be more likely to adopt positions that relinquish resources demanded by other individuals. Peterson et al. test this speculation:

Over human evolutionary history, upper-body strength has been a major component of fighting ability. Evolutionary models of animal conflict predict that actors with greater fighting ability will more actively attempt to acquire or defend resources than less formidable contestants will. Here, we applied these models to political decision making about redistribution of income and wealth among modern humans. In studies conducted in Argentina, Denmark, and the United States, men with greater upper-body strength more strongly endorsed the self-beneficial position: Among men of lower socioeconomic status (SES), strength predicted increased support for redistribution; among men of higher SES, strength predicted increased opposition to redistribution. Because personal upper-body strength is irrelevant to payoffs from economic policies in modern mass democracies, the continuing role of strength suggests that modern political decision making is shaped by an evolved psychology designed for small-scale groups.

Pathways through which loneliness affects health.

From Jaremka et al., some technical data on how stress correlates with activation of inflammatory chemistry in our bodies - chemistry started up by our immune system as if it were responding to infections or disease:

Although evidence suggests that loneliness may increase risk for health problems, the mechanisms responsible are not well understood. Immune dysregulation is one potential pathway: Elevated proinflammatory cytokines such as interleukin-6 (IL-6) increase risk for health problems. In our first study (N = 134), lonelier healthy adults exposed to acute stress exhibited greater synthesis of tumor necrosis factor-alpha (TNF-α) and IL-6 by peripheral blood mononuclear cells (PBMCs) stimulated with lipopolysaccharide (LPS) than their less lonely counterparts. Similarly, in the second study (N = 144), lonelier posttreatment breast-cancer survivors exposed to acute stress exhibited greater synthesis of IL-6 and interleukin-1 beta (IL-1β) by LPS-stimulated PBMCs than their counterparts who felt more socially connected. However, loneliness was unrelated to TNF-α in Study 2, although the result was in the expected direction. Thus, two different populations demonstrated that lonelier participants had more stimulated cytokine production in response to stress than less lonely participants, which reflects a proinflammatory phenotype. These data provide a glimpse into the pathways through which loneliness may affect health.

How exercise calms anxiety.

In my scans of journals' tables of contents I missed this interesting piece by Schoenfeld et al., which is pointed to by a summary in the New York Times "Well" section. Running is known to stimulate the production of more dendritic spines, the primary sites of excitatory synapses, on excitatory neurons throughout the hippocampal circuitry known to be involved in emotion processing. In spite of producing more excitable nerve tissue, exercise also calms anxiety (in mice and in humans). Schoenfeld suggest that this is because another effect of exercise is to increase the levels of proteins that process the inhibitory neurotransmitter GABA in local inhibitory nerve cells. Their results suggest that running improves anxiety regulation by engaging local inhibitory mechanisms in the ventral hippocampus. (By the way, GABA is a popular dietary supplement for supposedly calming social anxiety.) Here is their more technical abstract:

Physical exercise is known to reduce anxiety. The ventral hippocampus has been linked to anxiety regulation but the effects of running on this subregion of the hippocampus have been incompletely explored. Here, we investigated the effects of cold water stress on the hippocampus of sedentary and runner mice and found that while stress increases expression of the protein products of the immediate early genes c-fos and arc in new and mature granule neurons in sedentary mice, it has no such effect in runners. We further showed that running enhances local inhibitory mechanisms in the hippocampus, including increases in stress-induced activation of hippocampal interneurons, expression of vesicular GABA transporter (vGAT), and extracellular GABA release during cold water swim stress. Finally, blocking GABAA receptors in the ventral hippocampus, but not the dorsal hippocampus, with the antagonist bicuculline, reverses the anxiolytic effect of running. Together, these results suggest that running improves anxiety regulation by engaging local inhibitory mechanisms in the ventral hippocampus.