How to goose your memory.

The abstract from Inman et al., "Direct electrical stimulation of the amygdala enhances declarative memory in humans." They show that stimulation of the amygdala that does not elicit an emotional response during a neutral event enhances memory of that event. :

Significance

Memories for emotional events tend to persist, raising a fundamental question about how the brain prioritizes significant memories. Past studies have pointed to a central role for the amygdala in mediating this endogenous memory enhancement. However, the premise that the amygdala can causally enhance declarative memory has not been directly tested in humans. Here we show that brief electrical stimulation to the human amygdala can enhance declarative memory for specific images of neutral objects without eliciting a subjective emotional response, likely by engaging other memory-related brain regions. The results show the human amygdala has a general capacity to initiate enhancement of specific declarative memories rather than a narrower role limited to indirectly mediating emotional effects on memory.

Abstract

Emotional events are often remembered better than neutral events, a benefit that many studies have hypothesized to depend on the amygdala’s interactions with memory systems. These studies have indicated that the amygdala can modulate memory-consolidation processes in other brain regions such as the hippocampus and perirhinal cortex. Indeed, rodent studies have demonstrated that direct activation of the amygdala can enhance memory consolidation even during nonemotional events. However, the premise that the amygdala causally enhances declarative memory has not been directly tested in humans. Here we tested whether brief electrical stimulation to the amygdala could enhance declarative memory for specific images of neutral objects without eliciting a subjective emotional response. Fourteen epilepsy patients undergoing monitoring of seizures via intracranial depth electrodes viewed a series of neutral object images, half of which were immediately followed by brief, low-amplitude electrical stimulation to the amygdala. Amygdala stimulation elicited no subjective emotional response but led to reliably improved memory compared with control images when patients were given a recognition-memory test the next day. Neuronal oscillations in the amygdala, hippocampus, and perirhinal cortex during this next-day memory test indicated that a neural correlate of the memory enhancement was increased theta and gamma oscillatory interactions between these regions, consistent with the idea that the amygdala prioritizes consolidation by engaging other memory regions. These results show that the amygdala can initiate endogenous memory prioritization processes in the absence of emotional input, addressing a fundamental question and opening a path to future therapies.

Commentary on devolution of advanced societies towards tribalism.

I have been wanting to point to a number of Op-Ed articles that try to make a story to explain the apparent devolution of many advanced societies towards tribalism. Trump is a symptom, not a cause, of trends that have been growing for the past 30 years.

 Cohen notes:

Looking back, it’s now easy enough to see that the high point of democracy — the victory of open systems over the Soviet imperium that brought down the Berlin Wall in 1989 and set free more than 100 million Central Europeans — was quickly followed by the unleashing of economic forces that would undermine democracies. Far from ending history, liberalism triumphant engendered a reaction.

Increasingly, companies have been displacing nations as the units of international competition:

They optimize globally, rather than nationally. Their aim is to maximize profits across the world — allocating cash where it is most beneficial, finding labor where it is cheapest — not to pursue some national interest.

The shift was fast-forwarded by advances in communications that rendered distance irrelevant, and by the willingness in most emerging markets to open borders to foreign investment and new technologies.

Hundreds of millions of people in these developing countries were lifted from poverty into the middle class. Conversely, in Western societies, a hollowing out of the middle class began as manufacturing migrated, technological advances eliminated jobs and wages stagnated.

The global view did not suit everyone. In what the French call the “periphery” — areas far from the wired metropolis — it began to look like a not-so-subtle sabotaging of the nation. The moneyed got to run a rigged system, in a different universe from those whose lives remained local.

As inequality grew nationally (while narrowing globally), and impunity for financial disaster accompanied it, anger mounted. Frustration translated into an increasingly xenophobic search for scapegoats.

Three decades on, nationalism, nativism and illiberalism are ascendant, from Donald Trump’s United States, to Jaroslaw Kaczynski’s Poland, to Daw Aung San Suu Kyi’s Myanmar. It’s an astonishing turnabout, but it has its logic.

If we live today at an inflection point, it is because it’s impossible to say how much further rightist and illiberal authoritarianism may go.

Trump is a symptom, not a cause. That is why he may be hard to dislodge. He intuited the extent of American anger better than anyone. He also intuited a kind of cultural despair that made millions of Americans impervious to his lewd vulgarity — in fact, inclined to cheer him on in sticking it in the eye of the “establishment.”

An Op-Ed piece by David Brooks quotes Jonathan Haidt, who:

…listed some of the reasons centrifugal forces may now exceed centripetal: the loss of the common enemies we had in World War II and the Cold War, an increasingly fragmented media, the radicalization of the Republican Party, and a new form of identity politics, especially on campus... Haidt made the interesting point that identity politics per se is not the problem. Identity politics is just political mobilization around group characteristics. The problem is that identity politics has dropped its centripetal elements and become entirely centrifugal.

From an identity politics that emphasized our common humanity, we’ve gone to an identity politics that emphasizes having a common enemy. On campus these days, current events are often depicted as pure power struggles — oppressors acting to preserve their privilege over the virtuous oppressed.

“A funny thing happens,” Haidt said, “when you take young human beings, whose minds evolved for tribal warfare and us/them thinking, and you fill those minds full of binary dimensions. You tell them that one side in each binary is good and the other is bad. You turn on their ancient tribal circuits, preparing them for battle. Many students find it thrilling; it floods them with a sense of meaning and purpose.”

The problem is that tribal common-enemy thinking tears a diverse nation apart. This pattern is not just on campus. Look at the negative polarization that marks our politics. Parties, too, are no longer bound together by creeds but by enemies.

Brooks also cites Bruckner, who argues:

…that excessive individualism paradoxically leads to in-group/out-group tribalism. Modern individualism releases each person from social obligation, but “being guided only by the lantern of his own understanding, the individual loses all assurance of a place, an order, a definition. He may have gained freedom, but he has lost security.”..We each have to write our own gospel that defines our own virtue…The easiest way to do that is to tell a tribal oppressor/oppressed story and build your own innocence on your status as victim. Just about everybody can find a personal victim story. Once you’ve identified your herd’s oppressor — the neoliberal order, the media elite, white males, whatever — your goodness is secure. You have virtue without obligation. Nothing is your fault.

Finally Brooks notes that both Haidt and Bruckner:

...point to the fact that we’ve regressed from a sophisticated moral ethos to a primitive one. The crooked timber school of humanity says the line between good and evil runs through each person and we fight injustice on the basis of our common humanity. The oppressor/oppressed morality says the line runs between tribes. That makes it easy to feel good about yourself. But it makes you very hard to live with.

An essay by Thomas Edsall quotes thoughts emailed to him by Steven Pinker:

The answer lies in raw tribalism: when someone is perceived as a champion of one’s coalition, all is forgiven. The same is true for opinions: a particular issue can become a sacred value, shibboleth, or affirmation of allegiance to one’s team, and its content no longer matters. This is part of a growing realization in political psychology that tribalism has been underestimated in our understanding of politics, and ideological coherence and political and scientific literacy overestimated.

…the full ingenuity of human cognition is recruited to valorize the champion and shore up the sacred beliefs. You can always dismiss criticism as being motivated by the bias of one’s enemies. Our cognitive and linguistic faculties are endlessly creative — that’s what makes our species so smart — and that creativity can be always deployed to reframe issues in congenial or invidious terms.

Another quote from Pinker on tribalism is found in Galanes’ article on a conversation between Bill Gates and Pinker:

One of the biggest enemies of reason is tribalism. When people subscribe to an ideology, they suck up evidence that supports their preconceptions and filter out evidence that goes against them. Contrary to the belief of most scientists that denial of climate change is an effect of scientific illiteracy, it is not at all correlated with scientific literacy. People who believe in man-made climate change don’t know any more about climate or science than those who deny it. It’s almost perfectly correlated with left-wing versus right-wing orientation. And a move toward greater rationality would unbundle them and let evidence inform what the optimal policies ought to be.

And, a quote from Don Symons:

Our species is profoundly coalitional, and in most times and places moral prescriptions apply only to one’s in-group, not to humanity in general. I don’t see any evidence that we evolved innate, universal moral rules about how to treat all humans. That’s why history, as James Joyce said, is a nightmare. Prehistory is worse. I assume that coalitional-thinking is what Trump was getting at when he claimed that he could shoot someone on 5th Avenue and his base would still love him. It’s not that they feel that killing a random stranger for no reason is morally ok; it’s that loyalty to their coalition leader is primary.

Now.... This post is too long to start on ideas for correcting the trend towards tribalism. In a future MindBlog post I hope to summarize some articles suggesting ways to transcend tribalism.

Corporate social responsibility to counter the sociopathy of capitalism?

Sorkin describes a striking letter sent out to business leaders by BlackRock, the largest investment firm in the world. The article and letter are worth a read. In the absence of significant government action, is this the only hope for countering the automatic inequities that result from exercisings only the profit motive of capitalism? The letter informs..

..business leaders that their companies need to do more than make profits — they need to contribute to society as well if they want to receive the support of BlackRock.

Mr. Fink has the clout to make this kind of demand: His firm manages more than $6 trillion in investments through 401(k) plans, exchange-traded funds and mutual funds, making it the largest investor in the world, and he has an outsize influence on whether directors are voted on and off boards.

From his letter:

“Society is demanding that companies, both public and private, serve a social purpose,...To prosper over time, every company must not only deliver financial performance, but also show how it makes a positive contribution to society.”

“many governments are failing to prepare for the future, on issues ranging from retirement and infrastructure to automation and worker retraining...As a result, society increasingly is turning to the private sector and asking that companies respond to broader societal challenges.”

We can only hope.....

How our bones regulate our weight.

Jansson et al. report that bones have a gravity sensor that initiates metabolic changes that compensate for a sudden change in body weight to return the body to its desired homeostatic weight set point:

Significance

The only known homeostatic regulator of fat mass is the leptin system. We hypothesized that there is a second homeostat regulating body weight with an impact on fat mass. In this study we have added and removed weight loads from experimental animals and measured the effects on the biological body weight. The results demonstrate that there is a body weight homeostat that regulates fat mass independently of leptin. As the body weight-reducing effect of increased loading was dependent on osteocytes, we propose that there is a sensor for body weight in the long bones of the lower extremities acting as “body scales.” This is part of a body weight homeostat, “gravitostat,” that keeps body weight and body fat mass constant.

Abstract

Subjects spending much time sitting have increased risk of obesity but the mechanism for the antiobesity effect of standing is unknown. We hypothesized that there is a homeostatic regulation of body weight. We demonstrate that increased loading of rodents, achieved using capsules with different weights implanted in the abdomen or s.c. on the back, reversibly decreases the biological body weight via reduced food intake. Importantly, loading relieves diet-induced obesity and improves glucose tolerance. The identified homeostat for body weight regulates body fat mass independently of fat-derived leptin, revealing two independent negative feedback systems for fat mass regulation. It is known that osteocytes can sense changes in bone strain. In this study, the body weight-reducing effect of increased loading was lost in mice depleted of osteocytes. We propose that increased body weight activates a sensor dependent on osteocytes of the weight-bearing bones. This induces an afferent signal, which reduces body weight. These findings demonstrate a leptin-independent body weight homeostat (“gravitostat”) that regulates fat mass.

Taming modern Frankensteins

The Jan. 12 issue of Science Magazine has an interesting section of articles on the long shadow cast by Mary Shelley’s 200 year old Frankenstein tale. Shultz offers a toolbox for creating a modern monster, Kupferschmidt describes the writing of Bostrom and others concerned that artificial intelligence may lead to the extinction of Homo Sapiens,and Jon Cohen offers a glossary of Frankenwords that I paste in here:

Frankenbrooms

Supercoated broomheads used in curling, a winter sport played on ice.

Frankencell

J. Craig Venter's attempt to create an artificial cell containing the smallest possible number of essential genes.

Frankenfears

Exaggerated concerns about transgenic food (Frankenfood) and other products of genetic engineering.

Frankenforests

Engineered trees that grow more quickly, absorbing more carbon dioxide and providing more wood and pulp without the need for toxic chemicals.

Frankengene

The catechol-O-methyltransferase gene. In 2008, researchers linked variants in the gene to the strong, frightful reaction some people have to horror movies.

Frankenmoth

A male diamondback moth engineered to spread a lethal gene to females, creating nonviable offspring that reduce the moth's toll on crops. Cousins include Frankenflies and Frankenmosquitoes.

Frankenmouse

A genetically or surgically altered mouse. Variations have included the “oncomouse” that's prone to cancer and the “earmouse” that had a human-shaped ear.

Frankenmums

Mothers who freeze eggs for their infertile daughters to use.

Frankenpets

Transgenic dogs that would repel fleas; cats that would not cause allergies.

Frankenpines

Cellphone towers that resemble pine trees.

Frankenrobot

A robot, created at the University of Reading in the United Kingdom, that had a “brain” made of rat neurons placed on a multielectrode array.

Frankenshoes

Platform shoes with wedge heels or sneakers with heels.

Frankensites

University websites that have conflicting material posted by professors and their departments.

Frankenspuds

Genetically modified potatoes that are resistant to blight. Also known as Frankenfries.

Frankenstorm

A combination of storms that creates a monster event. Superstorm Sandy famously merged with another storm in 2012 to wallop the U.S. East Coast.

Preferences for moral vs. immoral traits in others are conditional

Wow, talk about work relevant to our current political situation...where some people (like myself) can not understand how anyone could support a president who is a sexual predator who has lied over 2,000 times since taking office and admitted zero of those lies. Menikoff and Bailey do straightforward experiments showing our preference for morality vs. immorality is conditional on the demands of our current goals, and not due solely to innate, “hardwired” links or personal learning experiences. Thus my intelligent Trump supporting friend says "I ignore Trump's behavior, and just note that things I want (more aggressive foreign poligy and tax cuts for the rich) are happening."

Significance

It is commonly argued that humans have a dominant preference for morality traits vs. immorality traits in others—that is, irrespective of the surrounding context, morality fosters liking, and immorality fosters disliking. The results of four experiments oppose this view by showing that situational goals can eliminate and even reverse the preference for morality vs. immorality in others. These findings suggest that our preference for morality vs. immorality is conditional on the demands of our current goals and cannot be attributed solely to innate, “hardwired” links or personal learning experiences. They also suggest that immoral people sometimes win public adoration, and the power that comes with it, not in spite of but precisely because of their immorality.

Abstract

The preference for morality in others is regarded as a dominant factor in person perception. Moral traits are thought to foster liking, and immoral traits are thought to foster disliking, irrespective of the context in which they are embedded. We report the results of four studies that oppose this view. Using both explicit and implicit measures, we found that the preference for morality vs. immorality in others is conditional on the evaluator’s current goals. Specifically, when immorality was conducive to participants’ current goals, the preference for moral vs. immoral traits in others was eliminated or reversed. The preferences for mercifulness vs. mercilessness (experiment 1), honesty vs. dishonesty (experiment 2), sexual fidelity vs. infidelity (experiment 3), and altruism vs. selfishness (experiment 4) were all found to be conditional. These findings oppose the consensus view that people have a dominant preference for moral vs. immoral traits in others. Our findings also speak to nativist and empiricist theories of social preferences and the stability of the “social contract” underlying productive human societies.

Self protection from social media feedback.

Rodman et al. show that adults and adolescents deal with peer feedback in very different ways:

Significance

The growing popularity of social media, especially among youth, has resulted in peer feedback (including rejection) pervading everyday life. Given that peer ostracism has been linked to depression and suicide, it is critical to understand the psychological impact of peer feedback from a developmental perspective. We demonstrate that adolescents and adults use peer feedback to inform views of themselves and of others in very different ways. Of particular interest, early adolescents internalized rejection from peers and felt worse about themselves, whereas adults exhibited evidence of self-protective biases that preserved positive self-views. This work advances theoretical insights into how development shapes social-evaluative experiences and informs sources of vulnerability that could put adolescents at unique risk for negative mental health outcomes.

Abstract

Adolescence is a developmental period marked by heightened attunement to social evaluation. While adults have been shown to enact self-protective processes to buffer their self-views from evaluative threats like peer rejection, it is unclear whether adolescents avail themselves of the same defenses. The present study examines how social evaluation shapes views of the self and others differently across development. N = 107 participants ages 10–23 completed a reciprocal social evaluation task that involved predicting and receiving peer acceptance and rejection feedback, along with assessments of self-views and likability ratings of peers. Here, we show that, despite equivalent experiences of social evaluation, adolescents internalized peer rejection, experiencing a feedback-induced drop in self-views, whereas adults externalized peer rejection, reporting a task-induced boost in self-views and deprecating the peers who rejected them. The results identify codeveloping processes underlying why peer rejection may lead to more dramatic alterations in self-views during adolescence than other phases of the lifespan.

The ‘social genomes’ of friends are correlated.

Here is an interesting study from Domingue et al.:

Significance

Our study reported significant findings of a “social genome” that can be quantified and studied to understand human health and behavior. In a national sample of more than 5,000 American adolescents, we found evidence of social forces that act to make friends and schoolmates more genetically similar to one another compared with random pairs of unrelated individuals. This subtle genetic similarity was observed across the entire genome and at sets of genomic locations linked with specific traits—educational attainment and body mass index—a phenomenon we term “social–genetic correlation.” We also find evidence of a “social–genetic effect” such that the genetics of a person’s friends and schoolmates influenced their own education, even after accounting for the person’s own genetics.

Abstract

Humans tend to form social relationships with others who resemble them. Whether this sorting of like with like arises from historical patterns of migration, meso-level social structures in modern society, or individual-level selection of similar peers remains unsettled. Recent research has evaluated the possibility that unobserved genotypes may play an important role in the creation of homophilous relationships. We extend this work by using data from 5,500 adolescents from the National Longitudinal Study of Adolescent to Adult Health (Add Health) to examine genetic similarities among pairs of friends. Although there is some evidence that friends have correlated genotypes, both at the whole-genome level as well as at trait-associated loci (via polygenic scores), further analysis suggests that meso-level forces, such as school assignment, are a principal source of genetic similarity between friends. We also observe apparent social–genetic effects in which polygenic scores of an individual’s friends and schoolmates predict the individual’s own educational attainment. In contrast, an individual’s height is unassociated with the height genetics of peers.

How much can we change our aging?

I'm using this post to point to the notes for a lecture on aging that I recently gave to a senior group in Austin Texas. It begins with a list of things over which we have little influence:

First would be our genetics. 50% of the odds of your dying in a given year is determined by your genetics, how long people in your family lineage have lived.

Second is disease. 50% of the chance that you will get a debilitating or terminal disease, especially cancer, is a throw of the dice, good or bad luck on whether particular genes randomly mutate to a bad place when cells divide, we get to influence only 30% of the risk of our getting cancer by changing lifestyle, diet, supplements, whatever.

Third would be our early life situation. 50% of what determines your cognitive vitality and intelligence in later life depends on how you started out - your intelligence when you were 11 years old. Your general cognitive ability with respect to your peers remains constant over your life course.

The bottom line is that ~2/3 of the odds of whether we are going go bonkers or croak at a given age is random chance, genetics, or early life experience over which we had no control.

The balance of the talk deals with the 30% or so of the odds we can influence: what we eat and drink, how we move, how we think, how we socialize.

Improving ourselves to death

Alexandra Schwartz notes a number of self help books and considers how their advice reflects the beliefs and priorities of our era. Here are a few clips:

In our current era of non-stop technological innovation, fuzzy wishful thinking has yielded to the hard doctrine of personal optimization. Self-help gurus need not be charlatans peddling snake oil. Many are psychologists with impressive academic pedigrees and a commitment to scientific methodologies, or tech entrepreneurs with enviable records of success in life and business. What they’re selling is metrics. It’s no longer enough to imagine our way to a better state of body or mind. We must now chart our progress, count our steps, log our sleep rhythms, tweak our diets, record our negative thoughts—then analyze the data, recalibrate, and repeat.

We are being sold on the need to upgrade all parts of ourselves, all at once, including parts that we did not previously know needed upgrading. (This may explain Yoni eggs, stone vaginal inserts that purport to strengthen women’s pelvic-floor muscles and take away “negative energy.” Gwyneth Paltrow’s Web site, Goop, offers them in both jade and rose quartz.) There is a great deal of money to be made by those who diagnose and treat our fears of inadequacy...We are under pressure to show that we know how to lead the perfect life.

The desire to achieve and to demonstrate perfection is not simply stressful; it can also be fatal, according to the British journalist Will Storr. “We’re living in an age of perfectionism, and perfection is the idea that kills...People are suffering and dying under the torture of the fantasy self they’re failing to become.”

If the ideal of the optimized self isn’t simply a fad, or even a preference, but an economic necessity, how can any of us choose to live otherwise? Storr insists that there is a way. “This isn’t a message of hopelessness,” he writes. “On the contrary, what it actually leads us towards is a better way of finding happiness. Once you realize that it’s all just an act of coercion, that it’s your culture trying to turn you into someone you can’t really be, you can begin to free yourself from your demands.”

Those for whom the imperative to “do you” feels like an unaffordable luxury may take some solace from Svend Brinkmann’s book “Stand Firm: Resisting the Self-Improvement Craze” ...The pace of life is accelerating, he says. We succumb to fleeting trends in food, fashion, and health. Technology has eroded the boundary between work and private life; we are expected to be constantly on call, to do more, “do it better and do it for longer, with scant regard for the content or the meaning of what we are doing.” Like Storr, Brinkmann condemns self-improvement as both a symptom and a tool of a relentless economy. But where Storr sees a health crisis, Brinkmann sees a spiritual one. His rhetoric is that of a prophet counselling against false idols. “In our secular world, we no longer see eternal paradise as a carrot at the end of the stick of life, but try to cram as much as possible into our relatively short time on the planet instead,” ... as Brinkmann’s title makes clear, standing still is precisely what he proposes that we do. Enough of our mania to be the best and the most, he says. It’s time to content ourselves with being average.

Brinkmann does offer some advice that seems immediately worth taking. Go for a walk in the woods, he says, and think about the vastness of the cosmos. Go to a museum and look at art, secure in the knowledge that it will not improve you in any measurable way. Things don’t need to be of concrete use in order to have value. Put away your self-help guides, and read a novel instead.

Explanation of fraternal birth order effect on sexual orientation.

A number of studies have by now confirmed that the probability of a boy growing up to be gay increases for each older brother born to the same mother, the so-called fraternal birth order (FBO) effect. Between 15% and 29% of gay men owe their sexual orientation to this effect. Bogaert et al. now present direct biochemical evidence indicating that the increased incidence of homosexuality in males with older brothers results from a progressive immunization of the mother against a male-specific cell-adhesion protein that plays a key role in cell–cell interactions, specifically in the process of synapse formation. Here are the details:

Significance

Gay men have, on average, a greater number of older brothers than do heterosexual men, a well-known finding within sexual science. This finding has been termed the fraternal birth order effect. Strong scientific interest in sexual orientation exists because it is a fundamental human characteristic, and because its origins are often the focal point of considerable social controversy. Our study is a major advance in understanding the origins of sexual orientation in men by providing support for a theorized but previously unexamined biological mechanism—a maternal immune response to a protein important in male fetal brain development—and by beginning to explain one of the most reliable correlates of male homosexuality: older brothers.

Abstract

We conducted a direct test of an immunological explanation of the finding that gay men have a greater number of older brothers than do heterosexual men. This explanation posits that some mothers develop antibodies against a Y-linked protein important in male brain development, and that this effect becomes increasingly likely with each male gestation, altering brain structures underlying sexual orientation in their later-born sons. Immune assays targeting two Y-linked proteins important in brain development—protocadherin 11 Y-linked (PCDH11Y) and neuroligin 4 Y-linked (NLGN4Y; isoforms 1 and 2)—were developed. Plasma from mothers of sons, about half of whom had a gay son, along with additional controls (women with no sons, men) was analyzed for male protein-specific antibodies. Results indicated women had significantly higher anti-NLGN4Y levels than men. In addition, after statistically controlling for number of pregnancies, mothers of gay sons, particularly those with older brothers, had significantly higher anti-NLGN4Y levels than did the control samples of women, including mothers of heterosexual sons. The results suggest an association between a maternal immune response to NLGN4Y and subsequent sexual orientation in male offspring.

Benefits of talking to yourself.

Talking to ourselves either internally or out loud we can switch from 1st person voice (I can do this) to second person (you can do this) or third person voice (Deric can do this). Kristin Wong does a piece pointing to several studies showing that this motivational self talk can lessen anxiety and improve performance. Focusing on the self from the distanced perspective of a third person, even though that person is you, enhances objectivity. Speaking the name of a familiar object out loud enhances its subsequent identification among random items. The work cited concluded that motivational self-talk works best on tasks based on speed, strength and power, while instructional self-talk works best with tasks that involved focus, strategy and technique.

Old brains come uncoupled in sleep.

From Helfrich et al.:

Highlights

•Precise coupling of NREM (Non-rapid-eye-movement) slow waves and spindles dictates memory consolidation 

•Aging impairs slow wave-spindle coupling, leading to overnight forgetting 

•Age-related atrophy in mPFC (medial prefrontal cortex) predicts the failure of such coupling and thus memory

Summary

The coupled interaction between slow-wave oscillations and sleep spindles during non-rapid-eye-movement (NREM) sleep has been proposed to support memory consolidation. However, little evidence in humans supports this theory. Moreover, whether such dynamic coupling is impaired as a consequence of brain aging in later life, contributing to cognitive and memory decline, is unknown. Combining electroencephalography (EEG), structural MRI, and sleep-dependent memory assessment, we addressed these questions in cognitively normal young and older adults. Directional cross-frequency coupling analyses demonstrated that the slow wave governs a precise temporal coordination of sleep spindles, the quality of which predicts overnight memory retention. Moreover, selective atrophy within the medial frontal cortex in older adults predicted a temporal dispersion of this slow wave-spindle coupling, impairing overnight memory consolidation and leading to forgetting. Prefrontal-dependent deficits in the spatiotemporal coordination of NREM sleep oscillations therefore represent one pathway explaining age-related memory decline.

How to detect that someone is sick.

Alexsson et al. do a study suggesting that you should look first for droopy eyelids and corners of the mouth, then also check for pale skin and lips, how puffy their faces look, eye redness, and tiredness. Here is their abstract:

Detection and avoidance of sick individuals have been proposed as essential components in a behavioural defence against disease, limiting the risk of contamination. However, almost no knowledge exists on whether humans can detect sick individuals, and if so by what cues. Here, we demonstrate that untrained people can identify sick individuals above chance level by looking at facial photos taken 2 h after injection with a bacterial stimulus inducing an immune response (2.0 ng kg−1 lipopolysaccharide) or placebo, the global sensitivity index being d′ = 0.405. Signal detection analysis (receiver operating characteristic curve area) showed an area of 0.62 (95% confidence intervals 0.60–0.63). Acutely sick people were rated by naive observers as having paler lips and skin, a more swollen face, droopier corners of the mouth, more hanging eyelids, redder eyes, and less glossy and patchy skin, as well as appearing more tired. Our findings suggest that facial cues associated with the skin, mouth and eyes can aid in the detection of acutely sick and potentially contagious people.

Figure - Averaged images of 16 individuals (eight women) photographed twice in a cross-over design, during experimentally induced (a) acute sickness and (b) placebo. Images made by Audrey Henderson, MSc, St Andrews University, using Psychomorph. Here, 184 facial landmarks were placed on each image before composites displaying the average shape, colour and texture were created

A Two-System Framework for understanding fear and anxiety.

LeDoux and Pine note that extensive study and understanding of how mammalian brains, including our own, detect and respond to threats has not led to significant improvements in clinical treatments. Their open source article suggests that a conceptual reframing is needed to distinguish two classes of responses elicited by threats. The graphics in the article provide useful summaries:

Tremendous progress has been made in basic neuroscience in recent decades. One area that has been especially successful is research on how the brain detects and responds to threats. Such studies have demonstrated comparable patterns of brain-behavior relationships underlying threat processing across a range of mammalian species, including humans. This would seem to be an ideal body of information for advancing our understanding of disorders in which altered threat processing is a key factor, namely, fear and anxiety disorders. But research on threat processing has not led to significant improvements in clinical practice. The authors propose that in order to take advantage of this progress for clinical gain, a conceptual reframing is needed. Key to this conceptual change is recognition of a distinction between circuits underlying two classes of responses elicited by threats: 1) behavioral responses and accompanying physiological changes in the brain and body and 2) conscious feeling states reflected in self-reports of fear and anxiety. This distinction leads to a “two systems” view of fear and anxiety. The authors argue that failure to recognize and consistently emphasize this distinction has impeded progress in understanding fear and anxiety disorders and hindered attempts to developmore effective pharmaceutical and psychological treatments. The two-system view suggests a new way forward.

Demonstrating reciprocity on a global scale.

In this age that seems characterized by increasing domestic and international chaos, I like to pass on any work that shows potential buffering or stability in our complex political and economic systems. Here is a contribution from Frank et al.; the open source article has useful graphics describing cooperation and reciprocity around the world:

Reciprocity stabilizes cooperation from the level of microbes all the way up to humans interacting in small groups, but does reciprocity also underlie stable cooperation between larger human agglomerations, such as nation states? Famously, evolutionary models show that reciprocity could emerge as a widespread strategy for achieving international cooperation. However, existing studies have only detected reciprocity-driven cooperation in a small number of country pairs. We apply a new method for detecting mutual influence in dynamical systems to a new large-scale data set that records state interactions with high temporal resolution. Doing so, we detect reciprocity between many country pairs in the international system and find that these reciprocating country pairs exhibit qualitatively different cooperative dynamics when compared to nonreciprocating pairs. Consistent with evolutionary theories of cooperation, reciprocating country pairs exhibit higher levels of stable cooperation and are more likely to punish instances of noncooperation. However, countries in reciprocity-based relationships are also quicker to forgive single acts of noncooperation by eventually returning to previous levels of mutual cooperation. By contrast, nonreciprocating pairs are more likely to exploit each other’s cooperation via higher rates of defection. Together, these findings provide the strongest evidence to date that reciprocity is a widespread mechanism for achieving international cooperation.

Forget about major life extension - Aging is a fundamental feature of multicellular life

Nelson and Masel, present a theoretical argument summarized by Wagner in his brief essay on their paper. From Wagner:

Paul Nelson and Joanna Masel present a theoretical result showing that aging in multicellular organisms is inevitable. The argument is as simple as it is powerful. Cellular senescence is a well-known consequence of the second law of thermodynamics, due to mutations, epigenetic misregulation, and protein misfolding. Molecular accidents in a cell can happen and they consequently do happen. In unicellular organisms, life is maintained because of natural selection against senescent cells and, thus, at the population level life can continue potentially indefinitely. However, in multicellular organisms, competition among cells has been killed to ensure cooperation among cells and thus the integrity of the organism. Breakdown of cooperation and unchecked competition among cells is known as cancer. Cooperation, and thus limited competition among cells, leads to the accumulation of senescent cells, while competition among cells kills the organism because of a breakdown of cooperation.

The result presented by Nelson and Masel... is a negative theoretical prediction based on very few but fundamental features of reality: senescence is a consequence of the second law of thermodynamics (molecular accidents and degradation are inevitable); senescence can be countered by natural selection; but natural selection among cells undermines cooperation among the cells of a multicellular organism. Thus, the multicellular organism is doomed either by senescence or cancer. The fact that this result is a negative prediction, like those of Gödel in mathematics, also explains why it can have a law-like certainty. It does not depend on contingent evolved properties of organisms but only on those which are intrinsic to life itself, namely that organisms are physical systems subject to the limits of thermodynamics, natural selection, and the need for cooperation among the cells in multicellular organisms.

Exercise alters the microbiome, enhancing immune function.

Reynolds points to interesting work by Allen et al. showing that exercise by lean, but not obese, subjects enhances microbial production of short chain fatty acids that suppress tissue irritation and inflammation in the colon as well as the rest of the body. These short fatty acids also boost metabolism and dampen the insulin resistance that is a precursor to diabetes.

Memories are stored by the extracellular matrix surrounding brain cells.

Fascinating work from Thompson et al., who show that degrading the extracellular matrix structure with local injections into visual cortex area 2L of bacterial enzyme chondroitinase ABC can abolish a remote visual fear memory:

Significance

Perineuronal nets (PNNs), a type of extracellular matrix only found in the central nervous system, wraps tightly around the cell soma and proximal dendrites of a subset of neurons. The PNNs are long-lasting structures that restrict plasticity, making them eligible candidates for memory processing. This work demonstrates that PNNs in the lateral secondary visual cortex (V2L) are essential for the recall of a remote visual fear memory. The results suggest a role of extracellular molecules in storage and retrieval of memories.

Abstract

Throughout life animals learn to recognize cues that signal danger and instantaneously initiate an adequate threat response. Memories of such associations may last a lifetime and far outlast the intracellular molecules currently found to be important for memory processing. The memory engram may be supported by other more stable molecular components, such as the extracellular matrix structure of perineuronal nets (PNNs). Here, we show that recall of remote, but not recent, visual fear memories in rats depend on intact PNNs in the secondary visual cortex (V2L). Supporting our behavioral findings, increased synchronized theta oscillations between V2L and basolateral amygdala, a physiological correlate of successful recall, was absent in rats with degraded PNNs in V2L. Together, our findings suggest a role for PNNs in remote memory processing by stabilizing the neural network of the engram.

The narcissism epidemic is dead?

An interesting piece from Wetzel et al., who find no evidence for a commonly reported narcissism epidemic over the past 10-20 years, based on the perception that today’s popular culture encourages individuals to engage in self-inflation:

Are recent cohorts of college students more narcissistic than their predecessors? To address debates about the so-called “narcissism epidemic,” we used data from three cohorts of students (1990s: N = 1,166; 2000s: N = 33,647; 2010s: N = 25,412) to test whether narcissism levels (overall and specific facets) have increased across generations. We also tested whether our measure, the Narcissistic Personality Inventory (NPI), showed measurement equivalence across the three cohorts, a critical analysis that had been overlooked in prior research. We found that several NPI items were not equivalent across cohorts. Models accounting for nonequivalence of these items indicated a small decline in overall narcissism levels from the 1990s to the 2010s (d = −0.27). At the facet level, leadership (d = −0.20), vanity (d = −0.16), and entitlement (d = −0.28) all showed decreases. Our results contradict the claim that recent cohorts of college students are more narcissistic than earlier generations of college students.

Figure: Difference between latent means estimated in partial-invariance models as a function of cohort and trait. The means of the 1990s cohort were constrained to 0 for model identification. Mean differences between the 1990s and the 2000s cohorts and between the 1990s and 2010s cohorts can be interpreted as standard deviations. Error bars show ±1 SE of the estimated mean difference.