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.