Thursday, March 31, 2016

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.

Wednesday, March 30, 2016

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!

Tuesday, March 29, 2016

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.

Monday, March 28, 2016

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.

Friday, March 25, 2016

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
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.

Thursday, March 24, 2016

Suppressing memory of trauma causes forgetting of other memories.

An interesting article from Hulbert 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.

Wednesday, March 23, 2016

Vasopressin increases human risky cooperative behavior

From Brunnlieb et al.:

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.
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.

Tuesday, March 22, 2016

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.

Monday, March 21, 2016

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.

Friday, March 18, 2016

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... ).

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. 
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.

Thursday, March 17, 2016

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
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.

Wednesday, March 16, 2016

Tuesday, March 15, 2016

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:

•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

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.

Monday, March 14, 2016

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.

Friday, March 11, 2016

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.

Thursday, March 10, 2016

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.

Wednesday, March 09, 2016

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.

Tuesday, March 08, 2016

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.

Saturday, March 05, 2016

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.

Friday, March 04, 2016

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.
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.

Thursday, March 03, 2016

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 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.)

Wednesday, March 02, 2016

"Well-being" as a practiced skill

I thought I would pass on from the 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.

Tuesday, March 01, 2016

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.