Friday, April 19, 2019

Return of the oppressed.

An article written by Peter Turchin in 2013 notes that inequality moves in cycles, from the Roman Empire to our own Gilded Age, and he gives a chilling prediction about 2020: that inequality will have reached levels sufficient to cause violent social unrest (cf. threats of violence by Trump supporters if he does not win re-election in 2020.) I suggest you read the article, and include below his interesting graphic on American History

Inverse relationship between well-being and inequality in American history. The peaks and valleys of inequality (in purple) represent the ratio of the largest fortunes to the median wealth of households (the Phillips curve). The blue-shaded curve combines four measures of well-being: economic (the fraction of economic growth that is paid to workers as wages), health (life expectancy and the average height of native-born population), and social optimism (the average age of first marriage, with early marriages indicating social optimism and delayed marriages indicating social pessimism).

Thursday, April 18, 2019

New microscopy technique sees thousands of cells and their activity deep in the brain

Weisenberger et al. manage the amazing feat of imaging and recording activity of ~12,000 neurons in the mouse cortex. Here is their abstract and a clip from their Figure 7.

•In vivo Ca 2+ imaging of ∼12,000 neurons in mouse cortex at single-cell resolution
•Simultaneous 2p and 3p Ca 2+ imaging within 1,000 × 1,000 × 1,220 μm at up to 17 Hz
•Volumetric 3p Ca 2+ imaging of hippocampus through intact cortex 
•A new integrated, systems-wide optimized microscopy design paradigm
Calcium imaging using two-photon scanning microscopy has become an essential tool in neuroscience. However, in its typical implementation, the tradeoffs between fields of view, acquisition speeds, and depth restrictions in scattering brain tissue pose severe limitations. Here, using an integrated systems-wide optimization approach combined with multiple technical innovations, we introduce a new design paradigm for optical microscopy based on maximizing biological information while maintaining the fidelity of obtained neuron signals. Our modular design utilizes hybrid multi-photon acquisition and allows volumetric recording of neuroactivity at single-cell resolution within up to 1 × 1 × 1.22 mm volumes at up to 17 Hz in awake behaving mice. We establish the capabilities and potential of the different configurations of our imaging system at depth and across brain regions by applying it to in vivo recording of up to 12,000 neurons in mouse auditory cortex, posterior parietal cortex, and hippocampus.

Wednesday, April 17, 2019

McMindfulness - how capitalism captured the mindfulness industry

A great piece in The Guardian by David Forbes, an extract from his forthcoming book "Mindfulness and its Discontents" from which I further extract a few chunks:
On the internet is an image of Ronald McDonald, the McDonald’s hamburger icon, seated in a lotus position. Some Thai Buddhists see this in literal terms as disrespectful to the Buddha...The technical, neutral definition of mindfulness and its relativist lack of a moral foundation has opened up secular mindfulness to a host of dubious uses, now called out by its critics as McMindfulness...Instead of letting go of the ego, McMindfulness promotes self-aggrandizement; its therapeutic function is to comfort, numb, adjust and accommodate the self within a neoliberal, corporatized, militarized, individualistic society based on private gain...McMindfulness aims to reduce the stress of the private individual and does not admit to any interest in the social causes of does not grasp that an individualistic therapized and commodified society is itself a major generator of social suffering and distress. Instead, the best it can then do, ironically, is to offer to sell us back an individualistic, commodified “cure” – mindfulness – to reduce that distress...Meditation apps monetize mindfulness; Headspace’s revenue is estimated at $50m a year and the company is valued at $250m.

Tuesday, April 16, 2019

The New York Times Privacy Project

Many MindBlog readers are probably aware of the NYTimes series of articles on privacy, but I point to it for those who may not be. A recent piece by Ross Douthat describes how our emerging post-privacy isn't quite totalitarian, but it's getting there. I was particularly chilled by Valentino-DeVries' description of Google's Sensorvault database - a trove of detailed location records involving at least hundreds of millions of devices worldwide. Law enforcement officers are using it to identify possible suspects near crimes, and can obtain names and email addresses of device owners who appear relevant to the crime. The article has links to Google web pages that let you download all of your location history and any other data Google has on you. Other pages give instructions on deleting location, web, and App activity, as well as turning off such data collection.

Monday, April 15, 2019

Changes in well-being measured by massive online choice experiments.

Brynjolfsson et al. (open source) suggest moving beyond using gross domestic product (GDP) and productivity as a proxy for well-being to include the welfare gains from digital goods having zero price that are currently not captured in GDP.:

Gross domestic product (GDP) measures production and is not meant to measure well-being. While many people nonetheless use GDP as a proxy for well-being, consumer surplus is a better measure of consumer well-being. This is increasingly true in the digital economy where many digital goods have zero price and as a result the welfare gains from these goods are not reflected in GDP or productivity statistics. We propose a way of directly measuring consumer well-being using massive online choice experiments. We find that digital goods generate a large amount of consumer welfare that is currently not captured in GDP. For example, the median Facebook user needed a compensation of around $48 to give it up for a month.
Gross domestic product (GDP) and derived metrics such as productivity have been central to our understanding of economic progress and well-being. In principle, changes in consumer surplus provide a superior, and more direct, measure of changes in well-being, especially for digital goods. In practice, these alternatives have been difficult to quantify. We explore the potential of massive online choice experiments to measure consumer surplus. We illustrate this technique via several empirical examples which quantify the valuations of popular digital goods and categories. Our examples include incentive-compatible discrete-choice experiments where online and laboratory participants receive monetary compensation if and only if they forgo goods for predefined periods. For example, the median user needed a compensation of about $48 to forgo Facebook for 1 mo. Our overall analyses reveal that digital goods have created large gains in well-being that are not reflected in conventional measures of GDP and productivity. By periodically querying a large, representative sample of goods and services, including those which are not priced in existing markets, changes in consumer surplus and other new measures of well-being derived from these online choice experiments have the potential for providing cost-effective supplements to the existing national income and product accounts.

Friday, April 12, 2019

Tracking emotions of unseen persons by their context.

Martinez does a commentary on work by Chen and Whitney (open source) in the same issue of PNAS.  Here is a clip from that commentary:
Face perception is a fundamental component of our cognitive system and, arguably, a core ability that allowed humans to create the large, advanced societies of today. When we look at someone else’s face, we recognize who they are, whether they are female or male, attractive or unattractive, and happy or sad; that is, their affective state. Correctly interpreting these signals is essential for a functional, cooperative society. For example, when looking at the faces in Fig. 1, most people identify a female expressing sadness on the left and an angry male on the right. But while identity and other attributes are recognized quite accurately, affect is not. To see this, look at the images in Fig. 2A and B. What expressions would you now say these two individuals express? Most of us classify them as expressing excitement or euphoria; that is, positive emotions. What is behind this radical change in our interpretation of these images? Context. Our interpretation of a facial configuration is dependent on the context in which the facial expression is situated. In an ambitious new study in PNAS, Chen and Whitney show that people make reasonably good predictions of people’s affect when only the contextual information is known; that is, when the face is not observable (Fig. 2C). This inference is shown to be accurate, even when the whole body of the person is masked (Fig. 2D), thus preventing an inference based on body pose. Context, therefore, is not only necessary for a correct interpretation of how others feel but, in some instances, it is sufficient. This surprising result will provide renewed interest in the value that context plays in our interpretation of how others feel.
Fig. 1. When asked to identify the emotions shown in these images, most people agree that the left image expresses sadness, while the right image is a clear display of anger. If asked whether these expressions communicate positive or negative valence, most people agree that both correspond to a negative expression. The problem with these assessments is that context is not observable, which may lead to incorrect interpretations. Images courtesy of (Left) Imgflip and (Right) Getty Images/Michael Steele.

Fig. 2. Adding context to the facial expressions previously seen in Fig. 1 radically changes our interpretation of the emotion being experienced by a person. (A and B) In these two images, most observers agree that the people shown are experiencing a joyful event (i.e., positive valence). (C and D) When the face and body are blurred out, inference of valence and arousal is still possible. Images courtesy of (Upper Left, Lower Left, and Lower Right) Imgflip and (Upper Right) Getty Images/Michael Steele.

Here is the Chen and Whitney abstract:
Emotion recognition is an essential human ability critical for social functioning. It is widely assumed that identifying facial expression is the key to this, and models of emotion recognition have mainly focused on facial and bodily features in static, unnatural conditions. We developed a method called affective tracking to reveal and quantify the enormous contribution of visual context to affect (valence and arousal) perception. When characters’ faces and bodies were masked in silent videos, viewers inferred the affect of the invisible characters successfully and in high agreement based solely on visual context. We further show that the context is not only sufficient but also necessary to accurately perceive human affect over time, as it provides a substantial and unique contribution beyond the information available from face and body. Our method (which we have made publicly available) reveals that emotion recognition is, at its heart, an issue of context as much as it is about faces.

Thursday, April 11, 2019

Studies on brain renewal and enhancement

I want to point to two recent examples of studies on brain renewal in aging humans and other animals. First, a Stanford group finds that the normal decay in the effectiveness of the microglial brain cells that clean up brain garbage (protein deposits and cellular debris) correlates with the increased appearance of a single gene product, the B cell receptor protein CD22. They find that "Long-term central nervous system delivery of an antibody that blocks CD22 function reprograms microglia towards a homeostatic transcriptional state and improves cognitive function in aged mice."

Second, Zimmer does a nice review of work on the brain protein Klotho. Mice bred to make extra Klotho live 30 percent longer, and protects those with symptoms of Alzheimer's disease from cognitive decline. Klotho not only protects, but enhanced brain function, even in young mice. A recent study suggests that Klotho may also provide some protection from Alzheimer’s disease to people as well.

Wednesday, April 10, 2019

Synchronizing rhythmic brain circuits improves working memory in older adults.

Our short term memory depends on theta rhythms (~6-10 Hz) and gamma rhythms (~25-100 Hz) in different parts of our brain being coupled and in synchrony with each other. They become increasingly uncoordinated as we age, resulting in observable cognitive decline by the time we reach 60 or 70 years of age. Reinhart and Nguyen compare the working memory of subjects in their 20s with 60-70 year olds, and find that 25 min of noninvasive stimulation, frequency-tuned to individual brain network dynamics, dramatically improves the working memory of the older group, making it similar to the younger group.
Understanding normal brain aging and developing methods to maintain or improve cognition in older adults are major goals of fundamental and translational neuroscience. Here we show a core feature of cognitive decline—working-memory deficits—emerges from disconnected local and long-range circuits instantiated by theta–gamma phase–amplitude coupling in temporal cortex and theta phase synchronization across frontotemporal cortex. We developed a noninvasive stimulation procedure for modulating long-range theta interactions in adults aged 60–76 years. After 25 min of stimulation, frequency-tuned to individual brain network dynamics, we observed a preferential increase in neural synchronization patterns and the return of sender–receiver relationships of information flow within and between frontotemporal regions. The end result was rapid improvement in working-memory performance that outlasted a 50 min post-stimulation period. The results provide insight into the physiological foundations of age-related cognitive impairment and contribute to groundwork for future non-pharmacological interventions targeting aspects of cognitive decline.

Tuesday, April 09, 2019

Affective forecasting and partisanship

Rai summaries work by Dorison et al.:
Increasing political polarization is driven in part by voters selectively seeking views that support their preexisting beliefs and avoiding opposing views. Across several experiments, Dorison et al. found that people overestimate how upset they will be from being exposed to views from the opposing political party. For example, Clinton voters overestimated how upset they would be from watching Donald Trump's inaugural address or reading statements by Trump voters. This bias in affective forecasting occurs because voters underestimate their level of agreement with people from the opposite party. Correcting voters' affective forecasts increased their engagement with opposing views. These results have implications for fostering dialogue and reducing political polarization.
The Dorison et al. abstract:
People preferentially consume information that aligns with their prior beliefs, contributing to polarization and undermining democracy. Five studies (collective N = 2455) demonstrate that such “selective exposure” partly stems from faulty affective forecasts. Specifically, political partisans systematically overestimate the strength of negative affect that results from exposure to opposing views. In turn, these incorrect forecasts drive information consumption choices. Clinton voters overestimated the negative affect they would experience from watching President Trump's Inaugural Address (Study 1) and from reading statements written by Trump voters (Study 2). Democrats and Republicans overestimated the negative affect they would experience from listening to speeches by opposing-party senators (Study 3). People's tendency to underestimate the extent to which they agree with opponents’ views drove the affective forecasting error. Finally, correcting biased affective forecasts reduced selective exposure by 24–34% (Studies 4 and 5).

Monday, April 08, 2019

"Learned Helplessness" from constant attention to your input stream (email, etc.)?

I'm trying out a 'new rule' for myself (cf. the Real Time with Bill Maher show on HBO). I frequently wake with some new ideas that I want to develop and write about, then let that good intention to do productive generative work be blown away by glancing at and being hooked by emails and text messages that are continually running in background on the MacBook Air that I use for all my writing. The morning becomes submerged in attending to an never ending list of piddly details. I start feeling increasingly helpless and defined by reactivity to unpredictable input streams - like the experimental dogs in Seligman's classic "Learned Helplessness" experiments. My new rule - which I already violated this morning, but only once - is to carry the good ideas I wake up directly into further thinking and writing about them, completely ignoring the emails and text messages that have accumulated over the night. Going offline makes me feel powerful rather than helpless. Only after a significant period of being generative rather than reactive do I go back to glance at the input stream online. What I find is a pleasant simplification: many of the items I would have reacted to now get deleted without reading!

These sentiments are echoed by Goldfarb's recent NYTimes piece on how making yourself inaccessible from time to time is essential to boosting one's focus and effectiveness. I want to pass on clips of that essay, which contains links to the work referenced.
A 2017 survey from the American Psychological Association found that being constantly and permanently reachable on an electronic device — checking work emails on your day off; continuously cycling through social media feeds; responding to text messages at all hours — is associated with higher stress levels.
This phenomenon of always being reachable is what Linda Stone, a former Apple and Microsoft executive, calls continuous partial attention. Unlike multitasking — juggling activities of similar importance that don’t require too much cognitive processing — C.P.A. is a state of alertness during which you’re motivated by the desire not to miss out on anything.
Ms. Stone, who gives lectures and consults on issues relating to technology and attention, describes C.P.A. as an “always-on, anywhere, anytime, any place behavior that involves an artificial sense of constant crisis.” Being distractible — allowing incessant beeps, flashes and trills to shatter any semblance of concentration — contributes to a strained lifestyle, she said. Half-paying attention to everything means you’re not able to fully pay attention to anything.
This kind of task switching comes with a cost. It’s called attention residue, a term established by Sophie Leroy, a professor at the Bothell School of Business at the University of Washington. In a 2009 study, Dr. Leroy found that if people transition their attention away from an unfinished task, their subsequent task performance will suffer. For example, if you interrupt writing an email to reply to a text message, it will take time to refocus when you turn your attention back to finishing your email. That little bit of time of adjusting your focus — the residue — compounds throughout the day. As we fragment our attention, fatigue and stress increases, which negatively affects performance.

Friday, April 05, 2019

The life prospects of female co-twins are diminished by prenatal testosterone from their male twins.

From Bütikofe et al.:
During sensitive periods in utero, gonadal steroids help organize biological sex differences in humans and other mammals. In litter-bearing species, chromosomal females passively exposed to prenatal testosterone from male littermates exhibit altered physical and behavioral traits as adults. The consequences of such effects are less well understood in humans, but recent near-doubling of twinning rates in many countries since 1980, secondary to advanced maternal age and increased reliance on in vitro fertilization, means that an increasing subset of females in many populations may be exposed to prenatal testosterone from their male co-twin. Here we use data on all births in Norway (n = 728,842, including 13,800 twins) between 1967 and 1978 to show that females exposed in utero to a male co-twin have a decreased probability of graduating from high school (15.2%), completing college (3.9%), and being married (11.7%), and have lower fertility (5.8%) and life-cycle earnings (8.6%). These relationships remain unchanged among the subsets of 583 and 239 females whose male co-twin died during the first postnatal year and first 28 days of life, respectively, supporting the interpretation that they are due primarily to prenatal exposure rather than to postnatal socialization effects of being raised with a male sibling. Our findings provide empirical evidence, using objectively measured nation-level data, that human females exposed prenatally to a male co-twin experience long-term changes in marriage, fertility, and human capital. These findings support the hypothesis of in utero testosterone transfer between twins, which is likely affecting a small but growing subset of females worldwide.

Thursday, April 04, 2019

One mechanism of a basic life choice - to ‘go for it’ or to ‘scram’

Miller et al. use a variety of methods to find subpopulations of dopamine sensitive neurons in the amygdala of mice, projecting to different brain areas, that become active either either during explorative approach or threat-avoiding behaviors:
Avoidance of innate threats is often in conflict with motivations to engage in exploratory approach behavior. The neural pathways that mediate this approach–avoidance conflict are not well resolved. Here we isolated a population of dopamine D1 receptor (D1R)-expressing neurons within the posteroventral region of the medial amygdala (MeApv) in mice that are activated either during approach or during avoidance of an innate threat stimulus. Distinct subpopulations of MeApv-D1R neurons differentially innervate the ventromedial hypothalamus and bed nucleus of the stria terminalis, and these projections have opposing effects on investigation or avoidance of threatening stimuli. These projections are potently modulated through opposite actions of D1R signaling that bias approach behavior. These data demonstrate divergent pathways in the MeApv that can be differentially weighted toward exploration or evasion of threats.

Wednesday, April 03, 2019

Students of color are healthier in schools that emphasize the value of diversity

From Levine et al.:

The United States is increasingly diverse, especially among youth. At the same time, racial and ethnic gaps persist in many domains, including risk for cardiovascular disease. Here, we use a diverse sample of adolescents in a mostly urban setting to show that when schools emphasize the value of diversity, students of color are healthier. Thus, schools’ climates around diversity may have a role to play in reducing health disparities.
As the United States becomes more diverse, the ways in which mainstream institutions recognize and address race and ethnicity will be increasingly important. Here, we show that one novel and salient characteristic of an institutional environment, that is, whether a school emphasizes the value of racial and ethnic diversity, predicts better cardiometabolic health among adolescents of color. Using a diverse sample of adolescents who attend more than 100 different schools in predominantly urban locations, we find that when schools emphasize the value of diversity (operationalized as mentioning diversity in their mission statements), students of color, but not white students, have lower values on a composite of five biomarkers of inflammation, have less insulin resistance and compensatory β-cell activity, and have fewer metabolic syndrome signs and score lower on a continuous metabolic syndrome composite. These results suggest that institutions that emphasize diversity may play an unacknowledged role in protecting the health of people of color and, thus, may be a site for future interventions to reduce health disparities.

Tuesday, April 02, 2019

American geography of opportunity reveals European origins

Interesting analysis from Berger and Engzell. They use microlevel Census data on self-reported ancestry to characterize the European origins of US places. They then examine whether variation in income inequality and intergenerational mobility across these places mirror differences between European countries. While parts of the Southeast contain places that are among the least mobile in the developed world, some areas in the Midwest show mobility rates similar to the Scandinavian countries. Evidence of stark regional divides that are seemingly stable over time suggests that some of this variation may be historical in origin. Their work confirms the inverse relationship between inequality and intergenerational mobility.

The United States is an immigrant nation and consists of places that differ widely in social, cultural, and economic makeup. Recent research finds striking regional variation in economic opportunity—the prospects of poor children to escape poverty as adults. Here, we show that the dominant European ancestry of a place does much to explain such differences: Levels of income equality and mobility across US communities with different European heritage mirror those across corresponding European countries. This finding sheds light on the historical roots of the American geography of opportunity.
A large literature documents how intergenerational mobility—the degree to which (dis)advantage is passed on from parents to children—varies across and within countries. Less is known about the origin or persistence of such differences. We show that US areas populated by descendants to European immigrants have similar levels of income equality and mobility as the countries their forebears came from: highest in areas dominated by descendants to Scandinavian and German immigrants, lower in places with French or Italian heritage, and lower still in areas with British roots. Similar variation in mobility is found for the black population and when analyzing causal place effects, suggesting that mobility differences arise at the community level and extend beyond descendants of European immigrant groups. Our findings indicate that the geography of US opportunity may have deeper historical roots than previously recognized.

Monday, April 01, 2019

Infants and toddlers expect different third party punishment behaviors from ingroup and outgroup members.

Yet another example of how our brains are wired to distinguish ingroup and outgroup at a very early age...Ting et al. find sophisticated social analysis performed by 1- and 2.5-year-olds, who show different expectations of the behavior of a third party who has viewed an ingroup-outgroup versus an ingroup-ingroup transgression:

Adults are more likely to punish transgressions that do not affect them when these transgressions victimize ingroup members. Such third-party punishment (TPP) often takes an indirect form, such as the withholding of help. Building on these results, we showed 2.5- and 1-year-olds scenarios involving a wrongdoer, a victim, and a bystander, and we manipulated the minimal-group memberships of the wrongdoer and the victim relative to that of the bystander. When the victim belonged to the bystander’s group, children expected TPP: They detected a violation when the bystander chose to help the wrongdoer. When the victim did not belong to the bystander’s group, however, children no longer expected TPP. Young children thus selectively expect indirect TPP for harm to ingroup members.
Adults and older children are more likely to punish a wrongdoer for a moral transgression when the victim belongs to their group. Building on these results, in violation-of-expectation experiments (n = 198), we examined whether 2.5-year-old toddlers (Exps. 1 and 2) and 1-year-old infants (Exps. 3 and 4) would selectively expect an individual in a minimal group to engage in third-party punishment (TPP) for harm to an ingroup victim. We focused on an indirect form of TPP, the withholding of help. To start, children saw a wrongdoer steal a toy from a victim while a bystander watched. Next, the wrongdoer needed assistance with a task, and the bystander either helped or hindered her. The group memberships of the wrongdoer and the victim were varied relative to that of the bystander and were marked with either novel labels (Exps. 1 and 2) or novel outfits (Exps. 3 and 4). When the victim belonged to the same group as the bystander, children expected TPP: At both ages, they detected a violation when the bystander chose to help the wrongdoer. Across experiments, this effect held whether the wrongdoer belonged to the same group as the bystander and the victim or to a different group; it was eliminated when the victim belonged to a different group than the bystander, when groups were not marked, and when either no theft occurred or the wrongdoer was unaware of the theft. Toddlers and infants thus expect individuals to refrain from helping an ingroup victim’s aggressor, providing further evidence for an early-emerging expectation of ingroup support.

Friday, March 29, 2019

Yet another longevity predictor?

The NYTimes and WaPo must have a substantial number of readers in my 75-80 year old demographic, an age interval during which physical capabilities are rapidly diminishing. Strout offers yet another article pointing to research on physical tests that measure of life expectancy:
The test requires you to lower yourself to the floor, crisscross style, without bracing yourself with your hands, knees, arms, or sides of your legs. If you can stand back up, again without the aid of those body parts, you’ve scored a perfect 10 (five points for sitting, five points for standing). You lose a point every time you support yourself with a forbidden joint or appendage...The researchers tested 2,002 adults 51 to 80 years old, and then followed them until a participant died or until the study concluded, which was a median of 6.3 years. In that time, 159 people died — only two of whom had scored a perfect 10. Those who had the lowest score of zero to three points had a risk of death that was five to six times higher than those who scored eight to 10 points.
...more variables apply to our health (and our longevity) than those this particular test focuses on. It’s important to remember that the study results are most relevant to those the same age as the subjects in the testing group, who were ages 51 and up — a point often lost in discussion. Most of the people who scored the lowest on the test were in the 76-to-80 age range, a group that generally experiences decreased mobility and coordination. The research also didn’t reveal the causes of the 159 deaths during the follow-up period. Should we assume they all died of complications from falling, instead of cardiovascular disease or cancer? We don’t know.
The article points to other work showing correlations between physical performance and health. Men who can complete 40 push-ups over a ten year period have a 96% lower risk of cardiovascular disease. People over 65 who walk one meter per second or faster live longer than those who can't.

Thursday, March 28, 2019

Using artificial intelligence for medical billing scams.

As a 76 year old Medicare beneficiary, I am frequently annoyed by the blatant ploys that medical care providers use to game the 'fee for services' system: notably scheduling unnecessary appointments and procedures. Metz and Smith describe how this behavior could be enhanced by a dark side of the use of A.I. in health care, as A.I. image analysis technology spreads across medicine, and systems are developed that can detect diabetic retinopathy, as well as lung and brain diseases.
Similar forms of artificial intelligence are likely to move beyond hospitals into the computer systems used by health care regulators, billing companies and insurance providers. Just as A.I. will help doctors check your eyes, lungs and other organs, it will help insurance providers determine reimbursement payments and policy fees.
Ideally, such systems would improve the efficiency of the health care system. But they may carry unintended consequences, a group of researchers at Harvard and M.I.T. warns. In a paper published on Thursday in the journal Science, the researchers raise the prospect of “adversarial attacks” — manipulations that can change the behavior of A.I. systems using tiny pieces of digital data. By changing a few pixels on a lung scan, for instance, someone could fool an A.I. system into seeing an illness that is not really there, or not seeing one that is.
...doctors, hospitals and other organizations could manipulate the A.I. in billing or insurance software in an effort to maximize the money coming their way...If an insurance company uses A.I. to evaluate medical scans, for instance, a hospital could manipulate scans in an effort to boost payouts. If regulators build A.I. systems to evaluate new technology, device makers could alter images and other data in an effort to trick the system into granting regulatory approval.
In their paper, the researchers demonstrated that, by changing a small number of pixels in an image of a benign skin lesion, a diagnostic A.I system could be tricked into identifying the lesion as malignant. Simply rotating the image could also have the same effect, they found.
Small changes to written descriptions of a patient’s condition also could alter an A.I. diagnosis: “Alcohol abuse” could produce a different diagnosis than “alcohol dependence,” and “lumbago” could produce a different diagnosis than “back pain."
In turn, changing such diagnoses one way or another could readily benefit the insurers and health care agencies that ultimately profit from them. Once A.I. is deeply rooted in the health care system, the researchers argue, business will gradually adopt behavior that brings in the most money.

Wednesday, March 27, 2019


Leucht and collaborators show that injured bones do not heal as well with age because of the increases in chronic inflammation that occur with aging.

As we age, our capacity for tissue repair and regeneration in response to injury declines. Accordingly, bone repair is delayed and impaired in older patients. At the cornerstone of bone healing is the skeletal stem/progenitor cell (SSPC), whose function and number diminishes with age. However, the mechanisms driving this decline remain unclear. Here, we identify age-associated inflammation (“inflamm-aging”) as the main culprit of SSPC dysfunction and provide support for a central role of NF-κB as a mediator of inflamm-aging. Our results show that modification of the inflammatory environment may be a translational approach to functionally rejuvenate the aged SSPC, thereby improving the regenerative capacity of the aged skeleton.
Aging is associated with impaired tissue regeneration. Stem cell number and function have been identified as potential culprits. We first demonstrate a direct correlation between stem cell number and time to bone fracture union in a human patient cohort. We then devised an animal model recapitulating this age-associated decline in bone healing and identified increased cellular senescence caused by a systemic and local proinflammatory environment as the major contributor to the decline in skeletal stem/progenitor cell (SSPC) number and function. Decoupling age-associated systemic inflammation from chronological aging by using transgenic Nfkb1KO mice, we determined that the elevated inflammatory environment, and not chronological age, was responsible for the decrease in SSPC number and function. By using a pharmacological approach inhibiting NF-κB activation, we demonstrate a functional rejuvenation of aged SSPCs with decreased senescence, increased SSPC number, and increased osteogenic function. Unbiased, whole-genome RNA sequencing confirmed the reversal of the aging phenotype. Finally, in an ectopic model of bone healing, we demonstrate a functional restoration of regenerative potential in aged SSPCs. These data identify aging-associated inflammation as the cause of SSPC dysfunction and provide mechanistic insights into its reversal.

Tuesday, March 26, 2019

Affect theory and the new age of anxiety.

Hua Hsu, in the March 25, 2019, issue of The New Yorker, does a fascinating presentation of the work and ideas of Lauren Berlant, whose writing is an example of new field of literary criticism, termed "affect theory", that focuses on nonlinguistic feelings and emotions. Here are a few clips from the article:
In October, 2011, the literary scholar and cultural theorist Lauren Berlant published “Cruel Optimism,” a meditation on our attachment to dreams that we know are destined to be dashed...We like to imagine that our life follows some kind of trajectory, like the plot of a novel, and that by recognizing its arc we might, in turn, become its author. But often what we feel instead is a sense of precariousness—a gut-level suspicion that hard work, thrift, and following the rules won’t give us control over the story, much less guarantee a happy ending. For all that, we keep on hoping, and that persuades us to keep on living...The persistence of the American Dream, Berlant suggests, amounts to a cruel optimism, a condition “when something you desire is actually an obstacle to your own flourishing.”
...our Sisyphean pursuit of the good life has high stakes, and its amalgam of fantasy and futility is something that we process as experience before we rationalize it in thought. These feelings, Berlant says, are the “body’s response to the world, something you’re always catching up to.”...We dream of swimming toward a beautiful horizon, but in truth, Berlant evocatively observed, we are constantly “dogpaddling around a space whose contours remain obscure.” What stories do we tell ourselves in order to stay afloat?
“The Hundreds” (Duke), Berlant’s latest book, co-written with Kathleen Stewart, an anthropologist at the University of Texas at Austin, grows out of ... short writing exercises. Each entry is an experiment in “following out the impact of things” in a hundred words, or a multiple of a hundred words...The result is a strange and captivating book.
In Berlant and Stewart’s hands, affect theory provides a way of understanding the sensations and resignations of the present, the normalized exhaustion that comes with life in the new economy. It is a way of framing uniquely modern questions: Where did the seeming surplus of emotionality that we see on the Internet come from, and what might it become? What new political feelings were being produced by the rudderless drift of life in the gig economy? What if millennials were unintelligible to their parents simply because they have resigned themselves to precariousness as life’s defining feature?
Berlant’s work can feel strangely and kindly optimistic...Maybe relinquishing or recalibrating our fantasies of the good life doesn’t lead to absolute darkness. It can simply be a matter of coming to grips with different possibilities of communion, figuring out who benefits from our collective weariness...But attentiveness to affect encourages us to imagine ourselves beyond the present: even if feelings of exhaustion, indifference, or disillusionment may have been naturalized, that doesn’t mean they’re natural...
“No one wants to be a bad or compromised kind of force in the world, but the latter is just inevitable,” Berlant once wrote in a short essay on her personal credos. “The question is how to develop ways to accentuate those contradictions, to interrupt their banality and to move them somewhere.” We can build worlds out of these small ambitions. We continue to write, even if it occasionally feels as though we were spinning our wheels, and we continue to live, even if it means giving up the certainty that our story is going to end the way we want it to. Writing on her blog a few years ago, Berlant issued what she described as her collective’s secret motto: “We refuse to be worn out.”

Monday, March 25, 2019

More green space in childhood, fewer psychiatric disorders in adulthood.

From Engemann et al.:
Urban residence is associated with a higher risk of some psychiatric disorders, but the underlying drivers remain unknown. There is increasing evidence that the level of exposure to natural environments impacts mental health, but few large-scale epidemiological studies have assessed the general existence and importance of such associations. Here, we investigate the prospective association between green space and mental health in the Danish population. Green space presence was assessed at the individual level using high-resolution satellite data to calculate the normalized difference vegetation index within a 210 × 210 m square around each person’s place of residence (∼1 million people) from birth to the age of 10. We show that high levels of green space presence during childhood are associated with lower risk of a wide spectrum of psychiatric disorders later in life. Risk for subsequent mental illness for those who lived with the lowest level of green space during childhood was up to 55% higher across various disorders compared with those who lived with the highest level of green space. The association remained even after adjusting for urbanization, socioeconomic factors, parental history of mental illness, and parental age. Stronger association of cumulative green space presence during childhood compared with single-year green space presence suggests that presence throughout childhood is important. Our results show that green space during childhood is associated with better mental health, supporting efforts to better integrate natural environments into urban planning and childhood life.

Friday, March 22, 2019

Neural signal diversity is increased by psychedelics

From Carhart-Harris and collaborators:
What is the level of consciousness of the psychedelic state? Empirically, measures of neural signal diversity such as entropy and Lempel-Ziv (LZ) complexity score higher for wakeful rest than for states with lower conscious level like propofol-induced anesthesia. Here we compute these measures for spontaneous magnetoencephalographic (MEG) signals from humans during altered states of consciousness induced by three psychedelic substances: psilocybin, ketamine and LSD. For all three, we find reliably higher spontaneous signal diversity, even when controlling for spectral changes. This increase is most pronounced for the single-channel LZ complexity measure, and hence for temporal, as opposed to spatial, signal diversity. We also uncover selective correlations between changes in signal diversity and phenomenological reports of the intensity of psychedelic experience. This is the first time that these measures have been applied to the psychedelic state and, crucially, that they have yielded values exceeding those of normal waking consciousness. These findings suggest that the sustained occurrence of psychedelic phenomenology constitutes an elevated level of consciousness - as measured by neural signal diversity.

Thursday, March 21, 2019

Knowing your own heart - distinguishing interoceptive accuracy and awareness

Garfinkel et al. categorize three different aspects of the internal bodily sensing (interoception) that informs our interactions with the external world, focusing on heartbeats - whose frequency and intensity vary with the degree of our emotional arousal (calm, anticipating, fearful, excited, etc.).

• Interoception refers to the signalling and perception of internal bodily sensations.
• We validate a three dimensional construct of interoception.
• This comprises: interoceptive accuracy, sensibility and awareness (metacognition).
• These interoceptive dimensions represent dissociable interoceptive processes.
• Interoceptive accuracy serves as the core (central) construct.
Interoception refers to the sensing of internal bodily changes. Interoception interacts with cognition and emotion, making measurement of individual differences in interoceptive ability broadly relevant to neuropsychology. However, inconsistency in how interoception is defined and quantified led to a three-dimensional model. Here, we provide empirical support for dissociation between dimensions of: (1) interoceptive accuracy (performance on objective behavioural tests of heartbeat detection), (2) interoceptive sensibility (self-evaluated assessment of subjective interoception, gauged using interviews/questionnaires) and (3) interoceptive awareness (metacognitive awareness of interoceptive accuracy, e.g. confidence-accuracy correspondence). In a normative sample (N = 80), all three dimensions were distinct and dissociable. Interoceptive accuracy was only partly predicted by interoceptive awareness and interoceptive sensibility. Significant correspondence between dimensions emerged only within the sub-group of individuals with greatest interoceptive accuracy. These findings set the context for defining how the relative balance of accuracy, sensibility and awareness dimensions explain cognitive, emotional and clinical associations of interoceptive ability.

Wednesday, March 20, 2019

Lethal mass partisanship

I think everyone should read this lucid piece by Thomas Edsall, which describes the emerging consensus on the stark biological and evolved psychological roots of the contempt. moral disgust, and aggression that individual members of right and left wing political groups are now directing toward members of the opposing camp, playing out a primitive tribal in-group/out-group dynamic that has ancient evolutionary roots in primate and other social animal behaviors. We seem to be tearing down the fragile political and legal structures, erected by framers of the US constitution, that allowed this country to at least briefly transcend the warring tribes scenario that has prevailed through most of human history.

Some clips of points that I found fascinating:
As partisan hostility deepens, there is one group that might ordinarily be expected to help pull the electorate out of this morass — the most knowledgeable and sophisticated voters... In “Understanding Partisan Cue Receptivity,” Bert N. Bakker and Yphtach Lelkes...find...the most active voters — those notably “high in cognitive resources” — are the most willing to accept policy positions endorsed by their party, and they are doing so not out of principle, but to affirm their identity as a Democrat or Republican. They are expressing “the desire to reach conclusions that are consistent with a valued identity.”
Ironically, reflective citizens, who are sometimes seen as ideal citizens, might be the subset of strong partisan identifiers most likely to fall in line with the party. Since higher levels of cognitive resources and partisan social identity are associated with higher levels of political activism, the effect may be self-reinforcing, wherein political elites polarize the strongly identified and cognitively reflective, who then elect more polarized elites. The democratic dilemma may not be whether low information citizens can learn what they need to know, but whether high information citizens can set aside their partisan predispositions.
And, some quotes from Steven Pinker:
Certainly there is a tribal flavor to political polarization. Men’s testosterone rises or falls on election night, depending on whether their side wins, just as it does on Super Bowl Sunday...the coalitions clustering at the poles are not tribes in the classical anthropological sense. Today’s left- and right-wingers for the most part aren’t inventing myths of shared blood and common ancestry, or binding together in ritual ordeals, or blending in appearance with a common uniform...I think we’re seeing a somewhat different psychological phenomenon: dynamically sorting ourselves into coalitions defined by moralistic condemnation of designated enemies.
From John Hibbing, a political scientist at the University of Nebraska,
...the central political issues of the day revolve around in-group versus out-group, the definition of the in-group, and the unity and security of the in-group...the problem today is that there are so few cross-cutting cleavages. There is only one cleavage and it is the most evolutionarily primal cleavage of them all...people became tribal because the fundamental substantive issues today are about tribe. We are a group-based species.
From Cosmides and Tooby at UC Santa Barbara,
The set of evolved programs that enable and drive warfare and politics strongly overlap with the set of evolved programs that drive human morality. The mapping of these evolved programs and their embedded circuit logic is only in its infancy, and we have only sketched out some of the known or predicted features of our coalitional and moral psychologies. However, progress in this enterprise holds out the possibility of gradually throwing light on some of the darkest areas of human life...everybody benefits from participating in groups of alliances and factions on different scales, and people also benefit by fractionating solidarity in such a way that those on the far side of the boundary seem undesirable, worth spurning, contemptible, deplorable.
And, the most sobering note from NYU psychologist Jonathan Haidt:
I am expecting that America’s political dysfunction and anger will worsen, and will continue to worsen even after Donald Trump leaves the White House....The reasons for my pessimism are that 1) social media gets ever more effective at drowning us in outrage; 2) overall trust in institutions continues to decline, which makes it seem ever more urgent that “our” side take total control; 3) the younger generations have not seen effective political institutions or norms during their lives, and also seem less adept at handling political disagreements; and 4) the norms of campus regarding call-out culture seem to be spreading quickly into business and many other institutions.

Tuesday, March 19, 2019

MRI can detect the content of decisions 11 seconds before they are made.

Goldhill points to and summarizes work of Koening-Rober and Pearson. Their abstract:
Is it possible to predict the freely chosen content of voluntary imagery from prior neural signals? Here we show that the content and strength of future voluntary imagery can be decoded from activity patterns in visual and frontal areas well before participants engage in voluntary imagery. Participants freely chose which of two images to imagine. Using functional magnetic resonance (fMRI) and multi-voxel pattern analysis, we decoded imagery content as far as 11 seconds before the voluntary decision, in visual, frontal and subcortical areas. Decoding in visual areas in addition to perception-imagery generalization suggested that predictive patterns correspond to visual representations. Importantly, activity patterns in the primary visual cortex (V1) from before the decision, predicted future imagery vividness. Our results suggest that the contents and strength of mental imagery are influenced by sensory-like neural representations that emerge spontaneously before volition.

Monday, March 18, 2019

Why science needs philosophy

I have always been in awe of the clarity and precision of the thinking of one of my Univ. of Wisconsin colleagues, philosopher Elliott Sober. He is one of the coauthors of a fascinating article on the uses science has for the tools of philosophers (for example, to clean up their fuzzy thinking.) The article might be a bit intense for many readers, but I recommend reading through it. Just a few clips:
...philosophy’s contribution can take at least four forms: the clarification of scientific concepts, the critical assessment of scientific assumptions or methods, the formulation of new concepts and theories, and the fostering of dialogue between different sciences, as well as between science and society.
An example of conceptual clarification:
The definition of stem cells is a prime example. Philosophy has a long tradition of investigating properties, and the tools in use in this tradition have recently been applied to describe “stemness,” the property that defines stem cells. One of us has shown that four different kinds of properties exist under the guise of stemness in current scientific knowledge (1). Depending on the type of tissue, stemness can be a categorical property (an intrinsic property of the stem cell, independent of its environment), a dispositional property (an intrinsic property of the stem cell that is controlled by the microenvironment), a relational property (an extrinsic property that can be conferred to non–stem cells by the microenvironment), or a systemic property (a property that is maintained and controlled at the level of the entire cell population).

Friday, March 15, 2019

Spinning drops!

Here is a really neat, gee whiz kind of study:

To make the water droplets spin, researchers first had to make sure they didn’t wet the surface they fell on—otherwise, they’d just splash. The researchers did this by coating alumina plates with a fluorinated nonstick coating, similar to those found in nonstick cooking pans. Next, they masked some regions of the surface and shone ultraviolet (UV) light on the entire plate. The regions exposed to the UV became highly “wettable,” meaning water touching those regions spread out immediately rather than bouncing back up. The team created several designs of the wettable regions, including one with spiral arms radiating out from a center, much like a pinwheel.
As the droplet bounds up from the patterned surface, the portions encountering the wettable spirals stick to the surface, whereas the parts of the droplet in contact with the water-repelling surface rebound immediately. This creates a set of unbalanced forces, pulling on the droplet more in some parts than in others, twisting it.

Thursday, March 14, 2019

Psychological underpinnings of politics

I want to point to a number of commentaries on psychological determinants of political behavior that have been languishing in my queue of potential posts...

How brain science could determine the election. A review of differences between liberals and conservatives in brain processes - with a strong genetic component - hat regulate risk tolerance, openness to novelty, fearfulness, etc.

Why Trump will win a second term. Amy Chozick discusses Trump's uncanny grasp, deriving from his experience as a reality show host, of how to keep people's attention by creating an unscripted drama that fills living rooms everywhere, providing entertainment value in the chaos.

The end of the two-party system. David Brooks describes the dissolution of political parties into warring clans competing for declining resources.

Our Culture of Contempt.  Arthur Brooks notes that the problem in America today is not incivility or intolerance, it is contempt for those with opposing views. This is based on motive attribution asymmetry, which leads one side to consider itself driven by benevolence while thinking the other side is motivated by evil and hatred.

Is there such a thing as an authoritarian voter?  Molly Worthen review work studying the psychological traits of voters who are attracted to authoritarian personalities. 

Wednesday, March 13, 2019

Why is it so hard for democracy to deal with inequality? The Brahmins vs the Merchants

I want to pass on an article that I wish I had made the subject of a longer post when it first appeared.

Thomas Edsall, in "Why is it so hard for democracy to deal with inequality" points to a Power Point presentation by Thomas Piketty, "Brahmin Left vs Merchant Right," that notes a straightforward answer:
Traditional parties of the left no longer represent the working and lower middle classes...the domination of the Democratic Party here (and of socialist parties in France) by voters without college or university degrees came to an end over the period from 1948 to 2017. Both parties are now led by highly educated voters whose interests are markedly different from those in the working class...The result, Piketty argues, is a political system that pits two top-down coalitions against each other...high-education elites vote for the left, while high-income/high-wealth elites for the right, i.e., intellectual elite (Brahmin Left) vs business elite (Merchant Right).

Tuesday, March 12, 2019

Social threat learning transfers to our decision making.

Lindström et al. (open source) demonstrate that threat associations acquired both by social observation (e.g., through video) and by instruction (e.g., through spoken language) strongly transfer to decision making. This transfer leads to maladaptive decisions when socially acquired associations are outdated rather than valid. The full text describes the three different experimental paradigms noted in the abstract below:

In today’s world, indirect exposure to threatening situations is more common than ever, as illustrated by footage of terror and disaster in social media. How do such social threat learning experiences shape our decisions? We found that learning about threats from both observation and verbal information strongly influenced decision making. As with learning from our own experience, this influence could be either adaptive or maladaptive depending on whether the social information provided accurate expectations about the environment. Our findings can help explain both adaptive and pathological behaviors resulting from the indirect exposure to threatening events.
In today’s world, mass-media and online social networks present us with unprecedented exposure to second-hand, vicarious experiences and thereby the chance of forming associations between previously innocuous events (e.g., being in a subway station) and aversive outcomes (e.g., footage or verbal reports from a violent terrorist attack) without direct experience. Such social threat, or fear, learning can have dramatic consequences, as manifested in acute stress symptoms and maladaptive fears. However, most research has so far focused on socially acquired threat responses that are expressed as increased arousal rather than active behavior. In three experiments (n = 120), we examined the effect of indirect experiences on behaviors by establishing a link between social threat learning and instrumental decision making. We contrasted learning from direct experience (i.e., Pavlovian conditioning) (experiment 1) against two common forms of social threat learning—social observation (experiment 2) and verbal instruction (experiment 3)—and how this learning transferred to subsequent instrumental decision making using behavioral experiments and computational modeling. We found that both types of social threat learning transfer to decision making in a strong and surprisingly inflexible manner. Notably, computational modeling indicated that the transfer of observational and instructed threat learning involved different computational mechanisms. Our results demonstrate the strong influence of others’ expressions of fear on one’s own decisions and have important implications for understanding both healthy and pathological human behaviors resulting from the indirect exposure to threatening events.

Monday, March 11, 2019

How sleep aids recovery from infection, may protect brain from Alzheimer's disease

Dimitrov et al. show how a good night's sleep accelerates recovering from an infection. Glue like proteins (integrins) used by immune system T cells to attach to virus particles and mark them for destruction are produced at greater levels during sleep. In the awake state, signaling molecules like adrenaline are produced at greater levels and inhibit integrin production, reducing the ability of T cells to attach to invading microbes. Here is their technical abstract:

Efficient T cell responses require the firm adhesion of T cells to their targets, e.g., virus-infected cells, which depends on T cell receptor (TCR)–mediated activation of β2-integrins. Gαs-coupled receptor agonists are known to have immunosuppressive effects, but their impact on TCR-mediated integrin activation is unknown. Using multimers of peptide major histocompatibility complex molecules (pMHC) and of ICAM-1—the ligand of β2-integrins—we show that the Gαs-coupled receptor agonists isoproterenol, epinephrine, norepinephrine, prostaglandin (PG) E2, PGD2, and adenosine strongly inhibit integrin activation on human CMV- and EBV-specific CD8+ T cells in a dose-dependent manner. In contrast, sleep, a natural condition of low levels of Gαs-coupled receptor agonists, up-regulates integrin activation compared with nocturnal wakefulness, a mechanism possibly underlying some of the immune-supportive effects of sleep. The findings are also relevant for several pathologies associated with increased levels of Gαs-coupled receptor agonists (e.g., tumor growth, malaria, hypoxia, stress, and sleep disturbances).

Also, Holth et al. show that sleep appears to have a direct protective effect on a key protein that drives AD pathology. They provide direct evidence that disrupting sleep, or stimulating excitatory neurons in brain nuclei that control wakefulness and arousal, promotes the release and spread of damaging tau aggregates across the brains of mice, and that sleep deprivation leads to increased extracellular Aβ and tau in people.
The sleep-wake cycle regulates interstitial fluid (ISF) and cerebrospinal fluid (CSF) levels of β-amyloid (Aβ) that accumulates in Alzheimer’s disease (AD). Furthermore, chronic sleep deprivation (SD) increases Aβ plaques. However, tau, not Aβ, accumulation appears to drive AD neurodegeneration. We tested whether ISF/CSF tau and tau seeding and spreading were influenced by the sleep-wake cycle and SD. Mouse ISF tau was increased ~90% during normal wakefulness versus sleep and ~100% during SD. Human CSF tau also increased more than 50% during SD. In a tau seeding-and-spreading model, chronic SD increased tau pathology spreading. Chemogenetically driven wakefulness in mice also significantly increased both ISF Aβ and tau. Thus, the sleep-wake cycle regulates ISF tau, and SD increases ISF and CSF tau as well as tau pathology spreading.

Friday, March 08, 2019

How many push-ups can you do? Predicting heart health...

Gretchen Reynolds points to work showing that men who could get through 40 or more push-ups had 96 percent less risk of heart problems in the next 10 years than those who quit at 10 or fewer.

Importance - Cardiovascular disease (CVD) remains the leading cause of mortality worldwide. Robust evidence indicates an association of increased physical fitness with a lower risk of CVD events and improved longevity; however, few have studied simple, low-cost measures of functional status.
Objective - To evaluate the association between push-up capacity and subsequent CVD event incidence in a cohort of active adult men.
Design, Setting, and Participants - Retrospective longitudinal cohort study conducted between January 1, 2000, and December 31, 2010, in 1 outpatient clinics in Indiana of male firefighters aged 18 years or older. Baseline and periodic physical examinations, including tests of push-up capacity and exercise tolerance, were performed between February 2, 2000, and November 12, 2007. Participants were stratified into 5 groups based on number of push-ups completed and were followed up for 10 years. Final statistical analyses were completed on August 11, 2018.
Main Outcomes and Measures - Cardiovascular disease–related outcomes through 2010 included incident diagnoses of coronary artery disease and other major CVD events. Incidence rate ratios (IRRs) were computed, and logistic regression models were used to model the time to each outcome from baseline, adjusting for age and body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared). Kaplan-Meier estimates for cumulative risk were computed for the push-up categories.
Results - A total of 1562 participants underwent baseline examination, and 1104 with available push-up data were included in the final analyses. Mean (SD) age of the cohort at baseline was 39.6 (9.2) years, and mean (SD) BMI was 28.7 (4.3). During the 10-year follow up, 37 CVD-related outcomes (8601 person-years) were reported in participants with available push-up data. Significant negative associations were found between increasing push-up capacity and CVD events. Participants able to complete more than 40 push-ups were associated with a significantly lower risk of incident CVD event risk compared with those completing fewer than 10 push-ups (IRR, 0.04; 95% CI, 0.01-0.36).
Conclusions and Relevance - The findings suggest that higher baseline push-up capacity is associated with a lower incidence of CVD events. Although larger studies in more diverse cohorts are needed, push-up capacity may be a simple, no-cost measure to estimate functional status.

Thursday, March 07, 2019

Control of OCD behavior by amygdala to prefrontal input.

Sun et al. find a brain circuit in mice regulating OCD behavior that in humans might be susceptible to non drug manipulations such as transcranial magnetic stimulation.

The pathophysiology underlying obsessive-compulsive disorder (OCD) remains unclear, leading to major challenges in the treatment of OCD patients. Here, we defined a projection from the basolateral amygdala glutamate neurons to the medial prefrontal cortex glutamate and GABA neurons and described the putative importance of this circuit in manifesting the checking symptoms of OCD in mice. In addition, the above major findings were further verified in an fMRI mouse study. These findings raise the possibility of developing optimal treatments for OCD that involve the use of nondrug approaches, such as transcranial magnetic stimulation, that target the converging pathways.
Obsessive-compulsive disorder (OCD) affects ∼1 to 3% of the world’s population. However, the neural mechanisms underlying the excessive checking symptoms in OCD are not fully understood. Using viral neuronal tracing in mice, we found that glutamatergic neurons from the basolateral amygdala (BLAGlu) project onto both medial prefrontal cortex glutamate (mPFCGlu) and GABA (mPFCGABA) neurons that locally innervate mPFCGlu neurons. Next, we developed an OCD checking mouse model with quinpirole-induced repetitive checking behaviors. This model demonstrated decreased glutamatergic mPFC microcircuit activity regulated by enhanced BLAGlu inputs. Optical or chemogenetic manipulations of this maladaptive circuitry restored the behavioral response. These findings were verified in a mouse functional magnetic resonance imaging (fMRI) study, in which the BLA–mPFC functional connectivity was increased in OCD mice. Together, these findings define a unique BLAGlu→mPFCGABA→Glu circuit that controls the checking symptoms of OCD.

Wednesday, March 06, 2019

Long term trends in politics - Trump is not an outlier

A sobering analysis from Jordan et al.:

Donald Trump and a small group of emerging leaders around the world have been labeled as outliers in the ways that they think and communicate with others. Are they really anomalies, or do they fit into larger political trends? This study adds to existing scholarship by analyzing two important psychological dimensions, analytic thinking and confidence, in 12 large corpora of political texts representing political leaders of various levels in both the United States and other countries as well as 4 corpora of cultural texts. Rather than being anomalous, linguistic analyses find that, over the last century, there have been consistent declines in analytic thinking and rises in confidence in the ways that political leaders communicate with the public.

From many perspectives, the election of Donald Trump was seen as a departure from long-standing political norms. An analysis of Trump’s word use in the presidential debates and speeches indicated that he was exceptionally informal but at the same time, spoke with a sense of certainty. Indeed, he is lower in analytic thinking and higher in confidence than almost any previous American president. Closer analyses of linguistic trends of presidential language indicate that Trump’s language is consistent with long-term linear trends, demonstrating that he is not as much an outlier as he initially seems. Across multiple corpora from the American presidents, non-US leaders, and legislative bodies spanning decades, there has been a general decline in analytic thinking and a rise in confidence in most political contexts, with the largest and most consistent changes found in the American presidency. The results suggest that certain aspects of the language style of Donald Trump and other recent leaders reflect long-evolving political trends. Implications of the changing nature of popular elections and the role of media are discussed.

Tuesday, March 05, 2019

Even 10 minutes of low intensity physical activity enhances executive function in older adults

Petrella et al. (open source) find that executive function in older adults is boosted almost immediately by low intensity exercise as brief as 10 minutes. When a group of 17 older adults with average age of 73 engaged moderate, heavy and very heavy levels of brief exercise, the authors found that the magnitude of the post-exercise executive function benefit did not vary that much with intensity. They evaluated executive function with a pre- and post-exercise antisaccade task. Antisaccades require that an individual look (i.e., saccade) mirror-symmetrical to a visual stimulus and result in longer reaction times, increased directional errors, and less accurate and more variable endpoints than their prosaccade (i.e., saccade to a target’s veridical location) counterparts. Here is the detailed abstract:

•Antisaccades assess executive function.
•Older adults show decreased antisaccade reaction times following exercise.
•The executive benefit is observed across moderate to very-heavy exercise intensities.
•Older adults demonstrate subtle executive-related aerobic exercise effects.
Ten minutes of aerobic or resistance training can ‘boost’ executive function in older adults. Here, we examined whether the magnitude of the exercise benefit is influenced by exercise intensity. Older adults (N = 17: mean age = 73 years) completed a volitional test to exhaustion (VO2peak) via treadmill to determine participant-specific moderate (80% of lactate threshold (LT)), heavy (15% of the difference between LT and VO2peak) and very-heavy (50% of the difference between LT and VO2peak) exercise intensities. Subsequently, in separate sessions all participants completed 10-min constant load single-bouts of exercise at each intensity. Pre- and post-exercise executive function were examined via the antisaccade task. Antisaccades require a saccade mirror-symmetrical to a target and extensive evidence has shown that antisaccades are supported via frontoparietal networks that demonstrate task-dependent changes following single-bout and chronic exercise. We also included a non-executive task (saccade to veridical target location; i.e., prosaccade) to determine whether a putative post-exercise benefit is specific to executive-related oculomotor control. Results showed that VO2 and psychological ratings of perceived exertion concurrently increased with increasing exercise intensity. As well, antisaccade reaction times showed a 24 ms (i.e., 8%) reduction from pre- to post-exercise assessments (p less than .001), whereas prosaccade values did not (p = .19). Most notably, the post-exercise change in antisaccade RTs did not reliably vary with exercise intensity. Further, for each exercise intensity participants’ cardiorespiratory fitness level was unrelated to the magnitude of the post-exercise executive benefit (ps greater than .13). Accordingly, an exercise duration as brief as 10-min provides a selective benefit to executive function in older adults across the continuum of moderate to very-heavy intensities.

Monday, March 04, 2019

Our emotional reward from music is modulated by dopamine.

Ferreri et al. present evidence that enhancing or inhibiting dopamine signaling using levodopa or risperidone modulates the pleasure experienced while listening to music:

In everyday life humans regularly seek participation in highly complex and pleasurable experiences such as music listening, singing, or playing, that do not seem to have any specific survival advantage. The question addressed here is to what extent dopaminergic transmission plays a direct role in the reward experience (both motivational and hedonic) induced by music. We report that pharmacological manipulation of dopamine modulates musical responses in both positive and negative directions, thus showing that dopamine causally mediates musical reward experience.
Understanding how the brain translates a structured sequence of sounds, such as music, into a pleasant and rewarding experience is a fascinating question which may be crucial to better understand the processing of abstract rewards in humans. Previous neuroimaging findings point to a challenging role of the dopaminergic system in music-evoked pleasure. However, there is a lack of direct evidence showing that dopamine function is causally related to the pleasure we experience from music. We addressed this problem through a double blind within-subject pharmacological design in which we directly manipulated dopaminergic synaptic availability while healthy participants (n = 27) were engaged in music listening. We orally administrated to each participant a dopamine precursor (levodopa), a dopamine antagonist (risperidone), and a placebo (lactose) in three different sessions. We demonstrate that levodopa and risperidone led to opposite effects in measures of musical pleasure and motivation: while the dopamine precursor levodopa, compared with placebo, increased the hedonic experience and music-related motivational responses, risperidone led to a reduction of both. This study shows a causal role of dopamine in musical pleasure and indicates that dopaminergic transmission might play different or additive roles than the ones postulated in affective processing so far, particularly in abstract cognitive activities.
From a review piece by Goupil and Aucouturier in the same PNAS issue:
This result is the latest development in an already remarkable series of studies by the groups of Robert Zatorre and Antoni Rodriguez-Fornells on the implication of the reward system in musical emotions. In their seminal 2001 study, Blood and Zatorre used the PET imaging technique to show that episodes of peak emotional responses to music (or musical “chills”) were associated with increased blood flow in the ventral striatum, the amygdala, and other brain regions associated with emotion and reward. In a 2011 follow-up study, Salimpoor et al. then relied on [11C]raclopride PET—a technique that allows estimating dopamine release in cerebral tissue—to show that peak emotional arousal during music listening is associated with the simultaneous release of dopamine in the bilateral dorsal and ventral striatum. With the increasing spatial resolution of fMRI techniques, in 2013 the same team was able to narrow in on a specific dopaminoceptive subregion of the ventral striatum, the nucleus accumbens (NAcc). Specifically, they found that NAcc activity during music listening is associated with how much money participants are subsequently willing to pay for the songs that they found pleasurable. In a final salvo to establish not only the correlational but also the causal implication of dopamine in musical pleasure, the authors have turned to directly manipulating dopaminergic signaling in the striatum, first by applying excitatory and inhibitory transcranial magnetic stimulation over their participants’ left dorsolateral prefrontal cortex, a region known to modulate striatal function, and finally, in the current study, by administrating pharmaceutical agents able to alter dopamine synaptic availability, both of which influenced perceived pleasure, physiological measures of arousal, and the monetary value assigned to music in the predicted direction.
The finding that music constitutes a privileged stimulus able to activate phylogenetically ancient systems involved in valuation and motivation may very well be interpreted as an indication that the human brain contains an adaptive neural specialization for processing music as a rewarding stimulus. As such, one might wonder whether the crucial question for future research is not so much whether music is rewarding, but rather why.

Friday, March 01, 2019

Mindfulness + acceptance training - randomized controlled trial shows prosocial effects, less loneliness

From Lindsay et al.:

Loneliness (i.e., feeling alone) and social isolation (i.e., being alone) are among the most robust known risk factors for poor health and accelerated mortality. Yet mitigating these social risk factors is challenging, as few interventions have been effective for both reducing loneliness and increasing social contact. Mindfulness interventions, which train skills in monitoring present-moment experiences with an orientation of acceptance, have shown promise for improving social-relationship processes. This study demonstrates the efficacy of a 2-wk smartphone-based mindfulness training for reducing loneliness and increasing social contact in daily life. Importantly, this study shows that developing an orientation of acceptance toward present-moment experiences is a critical mechanism for mitigating these social risk factors.
Loneliness and social isolation are a growing public health concern, yet there are few evidence-based interventions for mitigating these social risk factors. Accumulating evidence suggests that mindfulness interventions can improve social-relationship processes. However, the active ingredients of mindfulness training underlying these improvements are unclear. Developing mindfulness-specific skills—namely, (i) monitoring present-moment experiences with (ii) an orientation of acceptance—may change the way people perceive and relate toward others. We predicted that developing openness and acceptance toward present experiences is critical for reducing loneliness and increasing social contact and that removing acceptance-skills training from a mindfulness intervention would eliminate these benefits. In this dismantling trial, 153 community adults were randomly assigned to a 14-lesson smartphone-based intervention: (i) training in both monitoring and acceptance (Monitor+Accept), (ii) training in monitoring only (Monitor Only), or (iii) active control training. For 3 d before and after the intervention, ambulatory assessments were used to measure loneliness and social contact in daily life. Consistent with predictions, Monitor+Accept training reduced daily-life loneliness by 22% (d = 0.44, P = 0.0001) and increased social contact by two more interactions each day (d = 0.47, P = 0.001) and one more person each day (d = 0.39, P = 0.004), compared with both Monitor Only and control trainings. These findings describe a behavioral therapeutic target for improving social-relationship functioning; by fostering equanimity with feelings of loneliness and social disconnect, acceptance-skills training may allow loneliness to dissipate and encourage greater engagement with others in daily life.

Thursday, February 28, 2019

A ketamine inspired nasal spray for depression.

I pass on this New Atlas article link on a nasal spray based on ketamine (the party drug PCP or 'angel dust') that is likely to receive FDA approval soon. From the article (which has a link to a series on that site called Psychedelic medicine 101, describing formerly taboo substances now being found useful, cf. Michael Pollan's recent book "Changing your Mind"):
Originally developed decades ago as a novel anesthetic, ketamine has been undergoing a renaissance in recent years... Of course in the world of Big Pharma there is no money to be made investing in clinical trials for a decades-old drug past its patent. So in comes esketamine, a chemical cousin of ketamine with many similar pharmacological actions. Esketamine is roughly twice as strong as ketamine, eliminated by the body faster, and allegedly presents less negative dissociative symptoms when compared to its relative. For the most part, esketamine acts on the brain in similar ways to ketamine, except it doesn't influence a few key neurological receptors.
Johnson & Johnson has been developing an esketamine-based nasal spray to treat depression for several years. The treatment's development process has been undeniably rocky with two major clinical trials failing to prove the drug is more effective than placebo and some experts questioning its ultimate efficacy.
Ahead of a final FDA decision, expected by early March, an independent advisory committee was recently established to offer a recommendation on the treatment's efficacy. After evaluating a multitude of research submitted by the pharmaceutical company, the committee overwhelmingly voted 14-to-2 in favor of recommending the treatment.

Wednesday, February 27, 2019

New form of neural communication at a distance.

The branch of parapsychology that claims subtle sensing and psychological action at a distance might be heartened that they are finding a shred of supportive data in recent bizarre findings suggesting a new form of neural communication. It turns out that two pieces of brain tissue in close proximity can still communicate with each other even though they have been completely severed, leaving a gap between them. From Dickson's summary of work by Chiang et al.:
Chiang et al. show that slow periodic activity in a horizontal hippocampal slice preparation occurs through dendritic NMDA receptor‐dependent Ca2+ spiking, which is itself self‐generating and self‐propagating, via ephaptic interactions across neurons. Consistent with purely ephaptic transmission, this activity and its active propagation across the slice were resistant to pharmacological blockers of fast ionotropic chemical neurotransmission, as well as pharmacological blockade of electrical transmission via gap junctions. What is particularly compelling is that the activity could be not only modulated, but also eliminated or even regenerated by imposed electrical fields. Most shockingly, this activity could be transmitted from one side of a surgically severed slice to the other when the two cut edges were simply placed in close proximity. These surprising findings were further supported by a computer model of hippocampal circuitry.
Here are the key points listed in the Chiang et al. (open source) article:
Slow periodic activity can propagate with speeds around 0.1 m s−1 and be modulated by weak electric fields.
Slow periodic activity in the longitudinal hippocampal slice can propagate without chemical synaptic transmission or gap junctions, but can generate electric fields which in turn activate neighbouring cells.
Applying local extracellular electric fields with amplitude in the range of endogenous fields is sufficient to modulate or block the propagation of this activity both in the in silico and in the in vitro models.
Results support the hypothesis that endogenous electric fields, previously thought to be too small to trigger neural activity, play a significant role in the self‐propagation of slow periodic activity in the hippocampus.
Experiments indicate that a neural network can give rise to sustained self‐propagating waves by ephaptic coupling, suggesting a novel propagation mechanism for neural activity under normal physiological conditions.

Tuesday, February 26, 2019

The Neuroscience of ‘Rock-a-Bye Baby’

I've always wondered why I sleep like a baby when on a boat being slowly rocked by waves, so was intrigued by Friedman's recent piece pointing to work by Perrault et al. showing that a slow rocking motion not only improves sleep but also can help people consolidate memories overnight. This is because continuous rocking stimulation strengthens deep sleep via the neural entrainment of intrinsic sleep oscillations. The Perrault et al. summary:

•Rocking boosts deep sleep, sleep maintenance, and memory in healthy sleepers
•Fast spindles increase during rocking and synchronize with the slow oscillation up-state
• Rocking-induced overnight memory improvement relates to increased sigma activity
• Continuous rocking stimulation actively entrains intrinsic sleep oscillations
Sensory processing continues during sleep and can influence brain oscillations. We previously showed that a gentle rocking stimulation (0.25 Hz), during an afternoon nap, facilitates wake-sleep transition and boosts endogenous brain oscillations (i.e., EEG spindles and slow oscillations [SOs]). Here, we tested the hypothesis that the rhythmic rocking stimulation synchronizes sleep oscillations, a neurophysiological mechanism referred to as “neural entrainment.” We analyzed EEG brain responses related to the stimulation recorded from 18 participants while they had a full night of sleep on a rocking bed. Moreover, because sleep oscillations are considered of critical relevance for memory processes, we also investigated whether rocking influences overnight declarative memory consolidation. We first show that, compared to a stationary night, continuous rocking shortened the latency to non-REM (NREM) sleep and strengthened sleep maintenance, as indexed by increased NREM stage 3 (N3) duration and fewer arousals. These beneficial effects were paralleled by an increase in SOs and in slow and fast spindles during N3, without affecting the physiological SO-spindle phase coupling. We then confirm that, during the rocking night, overnight memory consolidation was enhanced and also correlated with the increase in fast spindles, whose co-occurrence with the SO up-state is considered to foster cortical synaptic plasticity. Finally, supporting the hypothesis that a rhythmic stimulation entrains sleep oscillations, we report a temporal clustering of spindles and SOs relative to the rocking cycle. Altogether, these findings demonstrate that a continuous rocking stimulation strengthens deep sleep via the neural entrainment of intrinsic sleep oscillations.

Monday, February 25, 2019

Female brains are younger than male brains.

Fascinating, from Goyal et al. (open source article):

Prior work has identified many sex differences in the brain, including during brain aging and in neurodegenerative diseases. Notably, many of these studies are performed by comparing age-matched females and males. Evolutionary theorists have predicted that females might have more youthful brains (neoteny) as compared with males, but until now findings in support of this theory have been limited to postmortem transcriptional analysis, some of which is contradictory. To test this hypothesis in vivo, we analyzed sex differences in a unique brain PET dataset in over 200 normal human adults across the adult life span. We find that in terms of brain metabolism, the adult female brain is on average a few years younger than the male brain.
Sex differences influence brain morphology and physiology during both development and aging. Here we apply a machine learning algorithm to a multiparametric brain PET imaging dataset acquired in a cohort of 20- to 82-year-old, cognitively normal adults (n = 205) to define their metabolic brain age. We find that throughout the adult life span the female brain has a persistently lower metabolic brain age—relative to their chronological age—compared with the male brain. The persistence of relatively younger metabolic brain age in females throughout adulthood suggests that development might in part influence sex differences in brain aging. Our results also demonstrate that trajectories of natural brain aging vary significantly among individuals and provide a method to measure this.