Non-invasive DIY brain stimulators are a bad idea.

I must admit that I've been sorely tempted to have a try with one of the transcranial magnetic or direct current stimulators, easily ordered from web vendors, whose use is claimed to enhance your smarts or chill you out. A meta-analysis by Smits et al. casts cold water on the prospects of these working as advertised.

Excessive emotional responses to stressful events can detrimentally affect psychological functioning and mental health. Recent studies have provided evidence that non-invasive brain stimulation (NBS) targeting the prefrontal cortex (PFC) can affect the regulation of stress-related emotional responses. However, the reliability and effect sizes have not been systematically analyzed. In the present study, we reviewed and meta-analyzed the effects of repetitive transcranial magnetic (rTMS) and transcranial direct current stimulation (tDCS) over the PFC on acute emotional stress reactivity in healthy individuals. Forty sham-controlled single-session rTMS and tDCS studies were included. Separate random effects models were performed to estimate the mean effect sizes of emotional reactivity. Twelve rTMS studies together showed no evidence that rTMS over the PFC influenced emotional reactivity. Twenty-six anodal tDCS studies yielded a weak beneficial effect on stress-related emotional reactivity (Hedges’ g = −0.16, CI95% = [−0.33, 0.00]). These findings suggest that a single session of NBS is insufficient to induce reliable, clinically significant effects but also provide preliminary evidence that specific NBS methods can affect emotional reactivity. This may motivate further research into augmenting the efficacy of NBS protocols on stress-related processes.

The deep historical roots of global economic inequality

Nathan Nunn does an article which describes how a substantial part of the world’s current income differences can be explained by the divergent effects of European contact globally, beginning in the late 15th century with Christopher Columbus’ arrival to the Americas in 1492, which resulted in a massive transfer of disease, food, ideas, and people between the Old World and the New World. The colonization of people of color by white Europeans and particularly the enslavement of black people starting ~500 year ago has left an enduring legacy that is hard to overcome.

I pass on Figure 1 from the paper and its discussion. It shows the evolution of economic prosperity, measured using the natural logarithm of real per capita gross domestic product, for different regions of the world from 1000 to 2000 CE.

1) The best predictor of a region’s relative income in a period is its income in the years prior. A perfect predictor of the relative ranking of regional prosperity in 2000 is the ranking in 1800. If one considers income further back in time (e.g., 1500), one finds that it is still a very good indicator, although not a perfect one.

2) The sizable differences in relative incomes that we observe today have not always been present. (Today, the richest countries in the world are about 42 times as rich as the poorest.) These differences appear to have first emerged in 1500 and to have increased starting in the 18th century, a process that has been called the “Great Divergence” (2).

3) Although there is a remarkable amount of historical persistence in comparative development, there are some important exceptions. In particular, the region “Western European offshoots,” which comprises land that today is Canada, United States, Australia, and New Zealand, moves from being the poorest region of the world in 1600 (and before) to the richest in 1800 (and after).

Changes in cerebral cortex functional organization in healthy elderly.

Sigh.... Chong et al. offer a picture of how my 78 year old brain is more muddled than that of a ~23 year old male.

SIGNIFICANCE STATEMENT

Cross-sectional studies have demonstrated age-related reductions in the functional segregation and distinctiveness of brain networks. However, longitudinal aging-related changes in brain functional modular architecture and their links to cognitive decline remain relatively understudied. Using graph theoretical and community detection approaches to study task-free functional network changes in a cross-sectional young and longitudinal healthy elderly cohort, we showed that aging was associated with global declines in network segregation, integration, and module distinctiveness, and specific declines in distinctiveness of higher-order cognitive networks. Further, such functional network deterioration was associated with poorer cognitive performance cross-sectionally. Our findings suggest that healthy aging is associated with system-level changes in brain functional modular organization, accompanied by functional segregation loss particularly in higher-order networks specialized for cognition.

Abstract

Healthy aging is accompanied by disruptions in the functional modular organization of the human brain. Cross-sectional studies have shown age-related reductions in the functional segregation and distinctiveness of brain networks. However, less is known about the longitudinal changes in brain functional modular organization and their associations with aging-related cognitive decline. We examined age- and aging-related changes in functional architecture of the cerebral cortex using a dataset comprising a cross-sectional healthy young cohort of 57 individuals (mean ± SD age, 23.71 ± 3.61 years, 22 males) and a longitudinal healthy elderly cohort of 72 individuals (mean ± baseline age, 68.22 ± 5.80 years, 39 males) with 2–3 time points (18–24 months apart) of task-free fMRI data. We found both cross-sectional (elderly vs young) and longitudinal (in elderly) global decreases in network segregation (decreased local efficiency), integration (decreased global efficiency), and module distinctiveness (increased participation coefficient and decreased system segregation). At the modular level, whereas cross-sectional analyses revealed higher participation coefficient across all modules in the elderly compared with young participants, longitudinal analyses revealed focal longitudinal participation coefficient increases in three higher-order cognitive modules: control network, default mode network, and salience/ventral attention network. Cross-sectionally, elderly participants also showed worse attention performance with lower local efficiency and higher mean participation coefficient, and worse global cognitive performance with higher participation coefficient in the dorsal attention/control network. These findings suggest that healthy aging is associated with whole-brain connectome-wide changes in the functional modular organization of the brain, accompanied by loss of functional segregation, particularly in higher-order cognitive networks.

A review on transcutaneous vagal nerve stimulation.

Colzato and Beste review the literature on cognitive effects of transcutaneous vagus nerve stimulation (tVNS), with a focus on studies on normal subjects suggesting that it might enhance memory and sharpen task relevant representations. I pass on a few clips from their text and also their abstract. Motivated readers can obtain the whole article by emailing me.

The focus of the present review article is not on clinical populations but on healthy humans and how especially auricular tVNS may be a useful neuromodulatory tool in cognitive neuroscience.

Only after commercially available auricular tVNS (NEMOS®) and cervical tVNS (gammaCore®) devices hit the market in the last few years, the idea of using tVNS as a tool for neuromodulation in cognitive neuroscience has been put forward.

Auricular tVNS is applied through a special earplug electrode to the outer ear, sending electrical impulses to the auricular branch of the vagus nerve, also called Alderman's nerve or Arnold's nerve. By doing so, the afferent (i.e., the thick-myelinated Aβ) fibers of Arnold's nerve are excited and the afferent signal propagates from peripheral nerves to nuclei in the brainstem, such as the locus coeruleus (LC) and the NST, and, ultimately, to intracranial subcortical (hippocampus) and cortical structures such as the insula, the prefrontal cortex (PFC) and the motor cortex. To date, auricular tVNS is applied to the left ear because of cardiac safety concerns, even 310 though, recently, these concerns have been challenged.

To date, most tVNS studies use commercially available stimulation devices. Usually, these are equipped with the following fixed parameters: frequency of 25 Hz, 200 μs pulse width, 30s on / 30s off-cycle, and current intensities up to 3 mA. Findings from animal studies, can thus not directly be transferred to study protocols in humans, since stimulation parameters can vary.

The reviewed literature indicates that the modulation of activation in the locus coeruleus and in th hippocampus and related NA release could be regarded as a possible working mechanism for the memory-enhancing effects of tVNS. Second, that increased cortical inhibition in the motor cortex and PFC due to high GABA levels in response to tVNS can facilitate response selection and inhibition processes via sharpening task-relevant representations and inhibiting competing responses.

Here is their abstract:

Brain stimulation approaches are important to gain causal mechanistic insights into the relevance of functional brain regions and/or neurophysiological systems for human cognitive functions. In recent years, transcutaneous vagus nerve stimulation (tVNS) has attracted considerable popularity. It is a noninvasive brain stimulation technique based on the stimulation of the vagus nerve. The stimulation of this nerve activates subcortical nuclei, such as the locus coeruleus and the nucleus of the solitary tract, and from there, the activation propagates to the cortex. Since tVNS is a novel stimulation technique, this literature review outlines a brief historical background of tVNS, before detailing underlying neurophysiological mechanisms of action, stimulation parameters, cognitive effects of tVNS on healthy humans, and, lastly, current challenges and future directions of tVNS research in cognitive functions. Although more research is needed, we conclude that tVNS, by increasing noradrenaline (NA) and gamma-aminobutyric acid (GABA) levels, affects NA and GABA-related cognitive performance. The review provides detailed background information how to use tVNS as a neuromodulatory tool in cognitive neuroscience and outlines important future leads of research on tVNS.

Effects of social media on well-being.

Allcott et al. do a fascinating study examining the effects of getting a random sample of Facebook users to deactivate their accounts for 4 weeks in exchange for $102.

The rise of social media has provoked both optimism about potential societal benefits and concern about harms such as addiction, depression, and political polarization. In a randomized experiment, we find that deactivating Facebook for the four weeks before the 2018 US midterm election (i) reduced online activity, while increasing offline activities such as watching TV alone and socializing with family and friends; (ii) reduced both factual news knowledge and political polarization; (iii) increased subjective well-being; and (iv) caused a large persistent reduction in post-experiment Facebook use. Deactivation reduced post-experiment valuations of Facebook, suggesting that traditional metrics may overstate consumer surplus.

Differential fertility makes society more conservative on family values

From Vogl and Freese:  

Significance

“Family values” conservatives in the United States have more children and more siblings than their compatriots. These patterns reflect the tendency of the more religious and less educated to have larger families and more conservative views on the family. Among Protestants, denominational differences play a role, with fundamentalist groups exhibiting larger families, less education, and greater conservatism. The causal pathways are unclear, but the patterns reshape society: Traditional-family conservatism is more prevalent than it would have been if each person had the same population share as his or her parents. This demographic phenomenon raises opposition to same-sex marriage and abortion by 3 to 4 percentage points. It accounts for 7.9 million of the nation’s 54.8 million opponents to same-sex marriage.

Abstract

Data from the General Social Survey indicate that higher-fertility individuals and their children are more conservative on “family values” issues, especially regarding abortion and same-sex marriage. This pattern implies that differential fertility has increased and will continue to increase public support for conservative policies on these issues. The association of family size with conservatism is specific to traditional-family issues and can be attributed in large part to the greater religiosity and lower educational attainment of individuals from larger families. Over the 2004 to 2018 period, opposition to same-sex marriage and abortion was 3 to 4 percentage points more prevalent than it would have been were traditional-family conservatism independent of family size in the current generation. For same-sex marriage, evolutionary forces have grown in relative importance as society as a whole has liberalized. As of 2018, differential fertility raised the number of US adults opposed to same-sex marriage by 17%, from 46.9 million to 54.8 million.

Older adults proactively downregulate anticipated negative affect.

Interesting work from Corbett et al. (open source):

Previous studies have only investigated age-related differences in emotional processing and encoding in response to, not in anticipation of, emotional stimuli. In the current study, we investigated age-related differences in the impact of emotional anticipation on affective responses and episodic memory for emotional images. Young and older adults were scanned while encoding negative and neutral images preceded by cues that were either valid or invalid predictors of image valence. Participants were asked to rate the emotional intensity of the images and to complete a recognition task. Using multivariate behavioral partial least squares (PLS) analysis, we found that greater anticipatory recruitment of the amygdala, ventromedial prefrontal cortex (vmPFC), and hippocampus in older adults predicted reduced memory for negative than neutral images and the opposite for young adults. Seed PLS analysis further showed that following negative cues older adults, but not young adults, exhibited greater activation of vmPFC, reduced activation of amygdala, and worse memory for negative compared with neutral images. To the best of our knowledge, this is the first study to provide evidence that the “positivity effect” seen in older adults’ memory performance may be related to the spontaneous emotional suppression of negative affect in anticipation of, not just in response to, negative stimuli.

Looking at pictures makes your brain’s visual cortex swell!

Wow, talk about dynamic neuroplasticity...Mansson et al (open source) take observations of how rapidly our brains can change to a whole new level. They show that our visual cortex gets bigger when viewing a picture versus a simple fixation cross.

Measuring brain morphology with non-invasive structural magnetic resonance imaging is common practice, and can be used to investigate neuroplasticity. Brain morphology changes have been reported over the course of weeks, days, and hours in both animals and humans. If such short-term changes occur even faster, rapid morphological changes while being scanned could have important implications. In a randomized within-subject study on 47 healthy individuals, two high-resolution T1-weighted anatomical images were acquired (á 263 s) per individual. The images were acquired during passive viewing of pictures or a fixation cross. Two common pipelines for analyzing brain images were used: voxel-based morphometry on gray matter (GM) volume and surface-based cortical thickness. We found that the measures of both GM volume and cortical thickness showed increases in the visual cortex while viewing pictures relative to a fixation cross. The increase was distributed across the two hemispheres and significant at a corrected level. Thus, brain morphology enlargements were detected in less than 263 s. Neuroplasticity is a far more dynamic process than previously shown, suggesting that individuals’ current mental state affects indices of brain morphology. This needs to be taken into account in future morphology studies and in everyday clinical practice.

Progress toward gender equality in the United States has slowed or stalled

From England et al.:

Significance

Social scientists have documented dramatic change in gender inequality in the last half century, sometimes called a “gender revolution.” We show dramatic progress in movement toward gender equality between 1970 and 2018, but also that in recent decades, change has slowed or stalled. The slowdown on some indicators and stall on others suggests that further progress requires substantial institutional and cultural change. Progress may require increases in men’s participation in household and care work, governmental provision of child care, and adoption by employers of policies that reduce gender discrimination and help both men and women combine jobs with family care responsibilities.

Abstract

We examine change in multiple indicators of gender inequality for the period of 1970 to 2018. The percentage of women (age 25 to 54) who are employed rose continuously until ∼2000 when it reached its highest point to date of 75%; it was slightly lower at 73% in 2018. Women have surpassed men in receipt of baccalaureate and doctoral degrees. The degree of segregation of fields of study declined dramatically in the 1970s and 1980s, but little since then. The desegregation of occupations continues but has slowed its pace. Examining the hourly pay of those aged 25 to 54 who are employed full-time, we found that the ratio of women’s to men’s pay increased from 0.61 to 0.83 between 1970 and 2018, rising especially fast in the 1980s, but much slower since 1990. In sum, there has been dramatic progress in movement toward gender equality, but, in recent decades, change has slowed and on some indicators stalled entirely.

Gender differences in the brain connections that predict intelligence.

From Jiang et al:

Scores on intelligence tests are strongly predictive of various important life outcomes. However, the gender discrepancy on intelligence quotient (IQ) prediction using brain imaging variables has not been studied. To this aim, we predicted individual IQ scores for males and females separately using whole-brain functional connectivity (FC). Robust predictions of intellectual capabilities were achieved across three independent data sets (680 subjects) and two intelligence measurements (IQ and fluid intelligence) using the same model within each gender. Interestingly, we found that intelligence of males and females were underpinned by different neurobiological correlates, which are consistent with their respective superiority in cognitive domains (visuospatial vs verbal ability). In addition, the identified FC patterns are uniquely predictive on IQ and its sub-domain scores only within the same gender but neither for the opposite gender nor on the IQ-irrelevant measures such as temperament traits. Moreover, females exhibit significantly higher IQ predictability than males in the discovery cohort. This findings facilitate our understanding of the biological basis of intelligence by demonstrating that intelligence is underpinned by a variety of complex neural mechanisms that engage an interacting network of regions—particularly prefrontal–parietal and basal ganglia—whereas the network pattern differs between genders.

Arthur Brooks launches a happiness column.

It seems a bit strange to launch a column on happiness during a pandemic, but the social isolation that has been forced on us provides us with more time to consider our lives and what really has meaning for us. Arthur Brooks, who teaches a class at the Harvard Business School on happiness, has now offered what is the first in a series of articles in The Atlantic on identifying the building blocks of subjective well-being. (The term well-being is preferred to happiness, because happiness is used to denote everything from a passing good mood to a deeper sense of meaning in life.) I recommend that you read Brooks' article, and pass on here edited chunks of text with three succinct equations he offers for well-being, equations having some variables you can have some influence over, and others that you can not easily change.  

Equation 1: Subjective Well-being = Genes + Circumstances + Habits

Studies of identical twins raised apart suggest that the genetic component of a person’s well-being is between 44 percent and 52 percent, that is, about half. Circumstances—the good and the bad that enter all of our lives—could make up as little as 10 percent or as much as 40 percent of your subjective well-being. Even if circumstances play a big role, however, most scholars think it doesn’t matter very much, because the effects of circumstance never last very long. Genes and circumstances aren’t a productive focus in your quest for happiness. But don’t worry, there’s one variable left that affects long-term well-being and is under our control: habits. To understand habits, we need Equation 2.

Equation 2: Habits = Faith + Family + Friends + Work

Enduring happiness comes from human relationships, productive work, and the transcendental elements of life...many different faiths and secular life philosophies can provide this happiness edge. The key is to find a structure through which you can ponder life’s deeper questions and transcend a focus on your narrow self-interests to serve others...Similarly, there is no magic formula for what shape your family and friendships should take.People who have loving relationships with family and friends thrive; those who don’t, don’t...One of the most robust findings in the happiness literature is the centrality of productive human endeavor in creating a sense of purpose in life...What makes work meaningful is not the kind of work it is, but the sense it gives you that you are earning your success and serving others.

Equation 3: Satisfaction = What you have ÷ What you want

The secret to satisfaction is to focus on the denominator of Equation 3. Don’t obsess about your haves; manage your wants, instead. Don’t count your possessions (or your money, power, prestige, romantic partners, or fame) and try to figure out how to increase them; make an inventory of your worldly desires and try to decrease them. Make a bucket list—but not of exotic vacations and expensive stuff. Make a list of the attachments in your life you need to discard. Then, make a plan to do just that. The fewer wants there are screaming inside your brain and dividing your attention, the more peace and satisfaction will be left for what you already have.

After offering the above three equations as the first class in the mechanics of building a life, Brooks promises in the coming months to offer further installments on the art and science of happiness.

By the way, since this is a post on the subject of happiness,  I want to also point to a recent Sam Harris podcast on the science of happiness - a conversation with Laurie Santos, who  teaches the most popular course offered at Yale, "The Science of WellBeing," and also hosts the popular podcast The Happiness Lab.

Two sources on the state of America

Like many MindBlog readers, I am reading countless articles on the current pandemic and its medical, economic, and social consequences. I generally restrain myself from noting them on MindBlog, worrying that readers have become as saturated as I have. However, I do want to point to two that do stand out:

First, In a Making Sense Podcast Sam Harris talks with General Stanley McChrystal and Chris Fussell about the Covid-19 pandemic. They discuss the nature of the ongoing crisis, the threat of a breakdown in social order, the problem of misinformation, the prospects of a nationwide lockdown, the trade off between personal freedom and safety, the threat of tyranny, the concerns about the global supply chain, concerns about the price of oil, safeguarding the 2020 Presidential election, and other topics. McChrystal was the commander of all American and coalition forces in Afghanistan, is now senior fellow at Yale University’s Jackson Institute for Global Affairs, and is founder of the McChrystal Group leadership institute.

Second, a piece by Leonhardt and Serkez in the New York Times opinion series “The America We Need” paints the most clear graphical picture I have seen of how inequality in America has grown to its current extreme, defining the struggle society faces after Coronavirus.

Psychedelic psychiatry's brave new world, and a new rapid-acting antidepressannt

I want to point to this open source article in Cell magazine, that provides an up to date review of resurrection of research into possible clinical uses of psychotropic compounds such as psilocybin.

After a legally mandated, decades-long global arrest of research on psychedelic drugs, investigation of psychedelics in the context of psychiatric disorders is yielding exciting results. Outcomes of neuroscience and clinical research into 5-Hydroxytryptamine 2A (5-HT2A) receptor agonists, such as psilocybin, show promise for addressing a range of serious disorders, including depression and addiction.

Also, a review by Krystal et al. notes FDA approval of the first mechanistically new treatment for depression in over sixty years - a form of ketamine (the party drug Special K, also used as an anesthetic.) Motivated readers can obtain the full text from me.

The discovery of the strikingly rapid and robust antidepressant effects of r/s-ketamine for the treatment of antidepressant-resistant symptoms of depression has led to new insights into the biology of antidepressants and the FDA approval of its s-isomer, Esketamine (Spravato), the first mechanistically new treatment for depression in over 60 years.

Stress can be enhancing.

Beibowitz and Crum do an Op-Ed piece that is worth a read, noting:

Over a decade of research — ours and that of others — suggests that it’s not the type or amount of stress that determines its impact. Instead, it’s our mind-set about stress that matters most.

The Authors note research showing that adopting a “stress-is-enhancing” mind-set does not diminish the amount of stress being experienced, but does minimize its harmful effects. They describe a three step process to harness the benefits of stress: Acknowledge your stress, own your stress, then leverage your stress to achieve your goals and connect more deeply with the things that matter most.

Self Help during the COVID-19 crisis.

MindBlog is getting bombarded by emails from websites and organizations wanting to advertise their advice on how to cope with our current crisis. The "infographics" that are offered are fronts for commercial sites wanting to sell you something, and I don't pass them on. I do want to pass on one Twitter, Reddit, and Facebook meme pointed out by a friend:

Also,  David Brooks' piece on mental health in the age of the coronavirus is worth reading...

The pandemic spreads an existential feeling of unsafety, which registers in the neurons around your heart, lungs and viscera. It alters your nervous system, changing the way you see and perceive threat..It’s very hard to grasp what’s going on so deep inside. “All trauma is preverbal,” Dr. Bessel van der Kolk writes in his book “The Body Keeps the Score.” “Rational brain is basically impotent to talk the emotional brain out of its own reality.”...The best way to combat this visceral sense of fear and disassociation is by having ... experiences of deep reciprocal attunement with others that make you feel viscerally safe...I asked the experts whether they thought it was possible to have this sort of deep, visceral attunement over the internet. They thought it was, as long you can see the other person’s face and hear vocal tone. “The internet is a huge variable in this pandemic,” Dr. van der Kolk told me. “We have a profound new way to comfort one another.”

The perils of nighttime dining

Kelly et al. show that lipids in late evening snacks are less likely to be oxidized and most likely to be stored as fats than lipids in morning meals. Circadian control of metabolism appears to control whether ingested food is oxidized or stored.:

Circadian (daily) regulation of metabolic pathways implies that food may be metabolized differentially over the daily cycle. To test that hypothesis, we monitored the metabolism of older subjects in a whole-room respiratory chamber over two separate 56-h sessions in a random crossover design. In one session, one of the 3 daily meals was presented as breakfast, whereas in the other session, a nutritionally equivalent meal was presented as a late-evening snack. The duration of the overnight fast was the same for both sessions. Whereas the two sessions did not differ in overall energy expenditure, the respiratory exchange ratio (RER) was different during sleep between the two sessions. Unexpectedly, this difference in RER due to daily meal timing was not due to daily differences in physical activity, sleep disruption, or core body temperature (CBT). Rather, we found that the daily timing of nutrient availability coupled with daily/circadian control of metabolism drives a switch in substrate preference such that the late-evening Snack Session resulted in significantly lower lipid oxidation (LO) compared to the Breakfast Session. Therefore, the timing of meals during the day/night cycle affects how ingested food is oxidized or stored in humans, with important implications for optimal eating habits.

The lockdown turns out to NOT be an introvert's paradise.

Contra my March 28 post on our current lock down being springtime for introverts, here are some slips from a salient article by Abby Ohlheiser that resonates with my experience of feeling overwhelmed by the demands of video conference meetings set up to replace what we have lost in person to person contacts:

...as people began to adjust to isolation, they started to find ways to bring their outside social lives into their homes. Living rooms that were once a sanctuary from people-filled offices, gyms, bars, and coffee shops became all those things at once. Calendars that had been cleared by social distancing suddenly refilled as friends, family, and acquaintances made plans to sip “quarantinis” at Zoom happy hours, hold Netflix viewing parties, or just catch up over Google hangouts.

People are coping with the coronavirus pandemic by upending their lives and attempting to virtually re-create what they lost. The new version, however, only vaguely resembles what we left behind. Everything is flattened and pressed to fit into the confines of chats and video-conference apps like Zoom, which was never designed to host our work and social lives all at once. The result, for introverts, extroverts, and everyone in between, is the bizarre feeling of being socially overwhelmed despite the fact that we’re staying as far away from each other as we can.

Turning down invitations to talk to people during a global pandemic can simultaneously be needed self-care and something that makes you feel like a bad friend...The only excuse is ‘I don’t want to,’ and no one wants to hear that right now...The reality is that introverts don’t want to be alone all the time, and extroverts can appreciate moments of quiet. But the division exists as a way to describe how people gather their energy: introverts charge up by having quiet time to process, and extroverts do it by socializing.

Video chat has become the go-to substitute for many people’s discarded social lives, the place where they can see the most of the people they can no longer be with. Zoom, FaceTime, and Google Hangouts are easy to use. But they have a way of making everything feel like a meeting. At a happy hour of 10 people in a bar, you can settle into a side conversation, step away for fresh air, or listen to a conversation while nursing your drink.

Rejuvenating aging human cells.

Nicholas Wade points to important work by Stanford researchers showing they can rejuvenate human cells by reprogramming them back to a youthful state.

A major cause of aging is thought to be the errors that accumulate in the epigenome, the system of proteins that packages the DNA and controls access to its genes.The Stanford team...say their method, designed to reverse these errors and walk back the cells to their youthful state, does indeed restore the cells’ vigor and eliminate signs of aging...The Stanford approach utilizes powerful agents known as Yamanaka factors, which reprogram a cell’s epigenome to its time zero, or embryonic state....In 2006 Dr. Shinya Yamanaka, a stem-cell researcher at Kyoto University, amazed biologists by showing that a cell’s fate could be reversed with a set of four transcription factors — agents that activate genes — that he had identified...the Stanford team described a feasible way to deliver Yamanaka factors to cells taken from patients, by dosing cells kept in cultures with small amounts of the factors.

The Stanford team extracted aged cartilage cells from patients with osteoarthritis and found that after a low dosage of Yamanaka factors the cells no longer secreted the inflammatory factors that provoke the disease. The team also found that human muscle stem cells, which are impaired in a muscle-wasting disease, could be restored to youth. Members of the Stanford team have formed a company, Turn Biotechnologies, to develop therapies for osteoarthritis and other diseases.

Brain regions that predict money choices also predict allocation of time to watching videos

People currently spend over 1 billion hours every day in attention markets watching video content, and the world’s second-most popular search engine is the video site youtube.com. Combining neuroimaging with a behavioral task, Tong et al. extend the neuroeconomic toolkit to find that brain activity in regions previously shown to predict allocation of money also predicted choices to allocate time to watching videos in the youtube.com attention market. They also find that sampled activity in a subset of these brain regions implicates anticipatory affect at video onset generalizes to forecast the frequency of choices to allocate time as well as the duration of time allocated to videos. Their abstract:

The growth of the internet has spawned new “attention markets,” in which people devote increasing amounts of time to consuming online content, but the neurobehavioral mechanisms that drive engagement in these markets have yet to be elucidated. We used functional MRI (FMRI) to examine whether individuals’ neural responses to videos could predict their choices to start and stop watching videos as well as whether group brain activity could forecast aggregate video view frequency and duration out of sample on the internet (i.e., on youtube.com). Brain activity during video onset predicted individual choice in several regions (i.e., increased activity in the nucleus accumbens [NAcc] and medial prefrontal cortex [MPFC] as well as decreased activity in the anterior insula [AIns]). Group activity during video onset in only a subset of these regions, however, forecasted both aggregate view frequency and duration (i.e., increased NAcc and decreased AIns)—and did so above and beyond conventional measures. These findings extend neuroforecasting theory and tools by revealing that activity in brain regions implicated in anticipatory affect at the onset of video viewing (but not initial choice) can forecast time allocation out of sample in an internet attention market.

Prosocial behavior can increase happiness in the short term but decrease it in the long term.

From Falk and Graeber:  

Significance

Governments around the world increasingly acknowledge the role of happiness as a societal objective and implement policies that target national wellbeing levels. Knowledge about the determinants of happiness, however, is still limited. A longstanding candidate is prosocial behavior. Our study empirically investigates the causal effect of prosocial behavior on happiness in a high-stakes decision experiment. While we confirm previous findings of a positive effect in the short term, our findings distinctly show that this effect is short lived and even reverses after some time. This study documents that prosocial behavior does not unequivocally increase happiness because prosocial spending naturally requires giving up something else, which may decrease happiness in its own right.

Abstract

Does prosocial behavior promote happiness? We test this longstanding hypothesis in a behavioral experiment that extends the scope of previous research. In our Saving a Life paradigm, every participant either saved one human life in expectation by triggering a targeted donation of 350 euros or received an amount of 100 euros. Using a choice paradigm between two binary lotteries with different chances of saving a life, we observed subjects’ intentions at the same time as creating random variation in prosocial outcomes. We repeatedly measured happiness at various delays. Our data weakly replicate the positive effect identified in previous research but only for the very short run. One month later, the sign of the effect reversed, and prosocial behavior led to significantly lower happiness than obtaining the money. Notably, even those subjects who chose prosocially were ultimately happier if they ended up getting the money for themselves. Our findings revealed a more nuanced causal relationship than previously suggested, providing an explanation for the apparent absence of universal prosocial behavior.