Why are some people more anxious than others? Brain correlates of trait anxiety.

Why does trait anxiety (the stable tendency to attend to, experience, and report negative emotions such as fears, worries, and anxiety across many situations) vary between individuals? Berry et al. have measured self-reported trait anxiety in healthy adults, examining its relationships with brain dopamine function (Most anxiolytic drugs target serotonergic and GABAergic neurotransmitter systems) and also examining functional connectivity within circuits implicated in anxiety regulation. This enabled them to probe the neural substrates of individual differences.

  Significance Statement

It is common wisdom that individuals vary in their baseline levels of anxiety. We all have a friend or colleague we know to be more “tightly wound” than others, or, perhaps, we are the ones marveling at others' ability to “just go with the flow.” Although such observations about individual differences within nonclinical populations are commonplace, the neural mechanisms underlying normal variation in trait anxiety have not been established. Using multimodal brain imaging in humans, this study takes initial steps in linking intrinsic measures of neuromodulator release and functional connectivity within regions implicated in anxiety disorders. Our findings suggest that in healthy adults, higher levels of trait anxiety may arise, at least in part, from reduced dopamine neurotransmission.

Abstract

Trait anxiety has been associated with altered activity within corticolimbic pathways connecting the amygdala and rostral anterior cingulate cortex (rACC), which receive rich dopaminergic input. Though the popular culture uses the term “chemical imbalance” to describe the pathophysiology of psychiatric conditions such as anxiety disorders, we know little about how individual differences in human dopamine neurochemistry are related to variation in anxiety and activity within corticolimbic circuits. We addressed this issue by examining interindividual variability in dopamine release at rest using [¹¹C]raclopride positron emission tomography (PET), functional connectivity between amygdala and rACC using resting-state functional magnetic resonance imaging (fMRI), and trait anxiety measures in healthy adult male and female humans. To measure endogenous dopamine release, we collected two [¹¹C]raclopride PET scans per participant. We contrasted baseline [¹¹C]raclopride D2/3 receptor binding and D2/3 receptor binding following oral methylphenidate administration. Methylphenidate blocks the dopamine transporter, which increases extracellular dopamine and leads to reduced [¹¹C]raclopride D2/3 receptor binding via competitive displacement. We found that individuals with higher dopamine release in the amygdala and rACC self-reported lower trait anxiety. Lower trait anxiety was also associated with reduced rACC–amygdala functional connectivity at baseline. Further, functional connectivity showed a modest negative relationship with dopamine release such that reduced rACC–amygdala functional connectivity was accompanied by higher levels of dopamine release in these regions. Together, these findings contribute to hypodopaminergic models of anxiety and support the utility of combining fMRI and PET measures of neurochemical function to advance our understanding of basic affective processes in humans.

[11C]

Is Superintelligence Impossible?

Andy Clarke does an interesting and concise commentary on a discussion between Daniel Dennett and David Chalmers. I pass on the final two paragraphs of Clark's comments and suggest you read the whole piece.

I think we can divide the space of possible AI minds into two reasonably distinct categories. One category comprises the “passive AI minds” that seemed to be the main focus of the Chalmers-Dennett exchange. These are driven by large data sets and optimize their performance relative to some externally imposed choice of “objective function” that specifies what we want them to do—win at GO, or improve paperclip manufacture. And Dennett and Chalmers are right—we do indeed need to be very careful about what we ask them to do, and about how much power they have to implement their own solutions to these pre-set puzzles.

The other category comprises active AIs with broad brush-strokes imperatives. These include Karl Friston’s Active Inference machines. AI’s like these spawn their own goals and sub-goals by environmental immersion and selective action. Such artificial agents will pursue epistemic agendas and have an Umwelt of their own. These are the only kind of AIs that may, I believe, end up being conscious of themselves and their worlds—at least in any way remotely recognizable as such to us humans. They are the AIs who could be our friends, or who could (if that blunt general imperative was played out within certain kinds of environment) become genuine enemies. It is these radicalized embodied AIs I would worry about most. At the same time (and for the same reasons) I’d greatly like to see powerful AIs from that second category emerge. For they would be real explorations within the vast space of possible minds.

Digital addiction and the attention economy.

Jia Tolentino's "What It Takes to Put Your Phone Away" is a broad essay on our digital addictions that focuses on two recent books: Cal Newport's “Digital Minimalism: Choosing a Focused Life in a Noisy World” and Jenny Odell's “How to Do Nothing: Resisting the Attention Economy." I strongly recommend that you read it. I am going to resist the impulse to pass on many choice clips of text, limiting myself to two:

Odell elegantly aligns the crisis in our natural world and the crisis in our minds: what has happened to the natural world is happening to us, she contends, and it’s happening on the same soon-to-be-irreparable scale. She sees “little difference between habitat restoration in the traditional sense and restoring habitats for human thought”; both are endangered by “the logic of capitalist productivity.” She believes that, by constantly disclosing our needs and desires to tech companies that sift through our selfhood in search of profit opportunities, we are neglecting, even losing, our mysterious, murky depths—the parts of us that don’t serve an ulterior purpose but exist merely to exist. The “best, most alive parts” of ourselves are being “paved over by a ruthless logic of use.”

On the monetization of attention:

Legislators might succeed in granting citizens more control over the data that they generate by using the Internet, but social-media companies will, presumably, continue to treat their users like little countries that can be strip-mined to make other people rich...We remain attached to these technologies in a way that is clearly affecting the health of the body politic. Newport insists that our Internet-fuelled lack of mental peace and quiet is a better explanation for the current wave of American anxiety than “the latest crisis—be it the recession of 2009 or the contentious election of 2016.”

A bit of digital detox - rehearsing a Mendelssohn Piano Trio

I have been fortunate to find in Austin TX two accomplished string players, violinist Andrea Gore and cellist Karen Foster Cason, who join me in sight reading interesting piano trios. We have decided to work up a few of the pieces we like to do for a house concert in late May, - a musical/social occasion of the sort I used to do in the 1860 stone schoolhouse that was the living room of my Twin Valley Road residence in Madison Wisconsin. I thought I would pass on to MindBlog readers a bit of our rehearsal this past Thursday, working on a Mendelssohn piano trio.

The "digital detox" phrase in this post's title is a clip from Jia Tolentino's recent New Yorker Article "What It Takes to Put Your Phone Away." I'm very much in the mood these days to get away from the "invasion of your cognitive landscape" that it describes and that I have permitted by being open to so many digital input streams as I spend a large fraction of my days hovering over screen and keyboard.

I find that the exercise of playing music is an antidote to this malaise, and I want to spend more time doing it. Don't be surprised if MindBlog posts become less frequent. Anyway, here is the 1st movement of the Mendelssohn Piano Trio No. 2 in C Minor, in a video recording done with my iPhone XS Max with a Shure condenser microphone plugged into its USB port:

Bringing dead brains back to life.

Work by Vrselja et al. on restoring brain function in pigs four hours after death has been extensively covered by the popular press. I want to pass on the abstract to their paper, and then one clip that shows how far away the recovery observed is from actually restoring brain function.

The brains of humans and other mammals are highly vulnerable to interruptions in blood flow and decreases in oxygen levels. Here we describe the restoration and maintenance of microcirculation and molecular and cellular functions of the intact pig brain under ex vivo normothermic conditions up to four hours post-mortem. We have developed an extracorporeal pulsatile-perfusion system and a haemoglobin-based, acellular, non-coagulative, echogenic, and cytoprotective perfusate that promotes recovery from anoxia, reduces reperfusion injury, prevents oedema, and metabolically supports the energy requirements of the brain. With this system, we observed preservation of cytoarchitecture; attenuation of cell death; and restoration of vascular dilatory and glial inflammatory responses, spontaneous synaptic activity, and active cerebral metabolism in the absence of global electrocorticographic activity. These findings demonstrate that under appropriate conditions the isolated, intact large mammalian brain possesses an underappreciated capacity for restoration of microcirculation and molecular and cellular activity after a prolonged post-mortem interval.

This beautiful work shows that the brain has a much greater capacity for restoration that had been realized. The authors were able to obtain intracellular recordings from hippocampus pyramidal cells. However:

Monitoring of electrical activity from the dorsal surface of the brain using clinical-grade surface grid electrodes and electrocorticography (ECoG; also known as intracranial electroencephalography, EEG) revealed that spontaneous global activity did not reemerge and that ECoG activity was isoelectric throughout BEx perfusion. This indicates that the organization and/or summation of synaptic activity of individual neurons was inadequate to elicit detectable network activity as assessed by ECoG.

Factfulness - Rosling's instinctual mental errors - Destiny, Single Perspective, Blame, Urgency

This is the final installment of several posts for my own benefit - making brief clips from the Rosling "Factfullness" book to encapsulate what he calls our 10 'basic instincts' - instinctual mental errors that we make - hoping this exercise will imprint them in my feeble memory and make me less likely to perform some of the mental errors he describes.

The Destiny Instinct (Chapter 7) - Many things (including people, countries, religions, and cultures) appear to be constant just because the change is happening slowly. Remember that even small, slow changes gradually add up to big changes. To control the destiny instinct, remember slow change is still change. Keep track of gradual improvements. A small change every year can translate to a huge change over decades. Update your knowledge. Some knowledge goes out of date quickly. Technology, countries, societies, cultures, and religions are constantly changing. Talk to Grandpa. If you want to be reminded of how values have changed, think about your grandparents’ values and how they differ from yours. Collect examples of cultural change. Challenge the idea that today’s culture must also have been yesterday’s, and will also be tomorrow’s.

The Single Perspective Instinct (Chapter 8) - Recognize that a single perspective can limit your imagination, and remember that it is better to look at problems from many angles to get a more accurate understanding and find practical solutions. To control the single perspective instinct, get a toolbox, not a hammer. Test your ideas. Don’t only collect examples that show how excellent your favorite ideas are. Have people who disagree with you test your ideas and find their weaknesses. Don’t claim expertise beyond your field: be humble about what you don’t know. Be aware too of the limits of the expertise of others. If you are good with a tool, you may want to use it too often. If your favorite idea is a hammer, look for colleagues with screwdrivers, wrenches, and tape measures. Be open to ideas from other fields. The world cannot be understood without numbers, and it cannot be understood with numbers alone. Love numbers for what they tell you about real lives. Beware of simple ideas and simple solutions. History is full of visionaries who used simple utopian visions to justify terrible actions. Welcome complexity. Combine ideas. Compromise. Solve problems on a case-by-case basis.

The Blame Instinct (Chapter 9) - Recognize when a scapegoat is being used and remember that blaming an individual often steals the focus from other possible explanations and blocks our ability to prevent similar problems in the future. To control the blame instinct, resist finding a scapegoat. Look for causes, not villains. When something goes wrong don’t look for an individual or a group to blame. Accept that bad things can happen without anyone intending them to. Instead spend your energy on understanding the multiple interacting causes, or system, that created the situation. Look for systems, not heroes. When someone claims to have caused something good, ask whether the outcome might have happened anyway, even if that individual had done nothing. Give the system some credit.

The Urgency Instanct (Chapter 10) - Recognize when a situation feels urgent and remember that it rarely is. To control the urgency instinct, take small steps. Take a breath. When your urgency instinct is triggered, your other instincts kick in and your analysis shuts down. Ask for more time and more information. It’s rarely now or never and it’s rarely either/or. Insist on the data. If something is urgent and important, it should be measured. Beware of data that is relevant but inaccurate, or accurate but irrelevant. Only relevant and accurate data is useful. Beware of fortune-tellers. Any prediction about the future is uncertain. Be wary of predictions that fail to acknowledge that. Insist on a full range of scenarios, never just the best or worst case. Ask how often such predictions have been right before. Be wary of drastic action. Ask what the side effects will be. Ask how the idea has been tested. Step-by-step practical improvements, and evaluation of their impact, are less dramatic but usually more effective.

Factfulness - Rosling's instinctual mental errors - Fear, Size, Generalization

I'm continuing posts for my own benefit - making brief clips from the Rosling "Factfullness" book to encapsulate what he calls our 10 'basic instincts' - instinctual mental errors that we make - hoping this exercise will imprint them in my feeble memory and make me less likely to perform some of the mental errors he describes. The next post in this series is here.

The Fear Instinct (Chapter 4) - Frightening things get our attention, but remember that these are not necessarily the most risky. Our natural fears of violence, captivity, and contamination make us systematically overestimate these risks. To control the fear instinct, calculate the risks. The world seems scarier than it is because what you hear about it has been selected—by your own attention filter or by the media—precisely because it is scary. The risk something poses to you depends not on how scared it makes you feel, but on a combination of two things. How dangerous is it? And how much are you exposed to it? Get calm before you carry on. When you are afraid, you see the world differently. Make as few decisions as possible until the panic has subsided.

The Size Instinct (Chapter 5) - When a lonely number seems impressive (small or large), remember that you could get the opposite impression if it were compared with or divided by some other relevant number. To control the size instinct, get things in proportion. Single numbers on their own are misleading and should make you suspicious. Always look for comparisons. Ideally, divide by something. The 80/20 rule. Have you been given a long list? Look for the few largest items and deal with those first. They are quite likely more important than all the others put together. Divide: Amounts and rates can tell very different stories. Rates are more meaningful, especially when comparing between different-sized groups. In particular, look for rates per person when comparing between countries or regions.

Remember that categories can be misleading. We can’t stop generalization and we shouldn’t even try. What we should try to do is to avoid generalizing incorrectly. To control the generalization instinct, question your categories. Look for differences within groups. Especially when the groups are large, look for ways to split them into smaller, more precise categories. And, look for similarities across groups. If you find striking similarities between different groups, consider whether your categories are relevant. But also, look for differences across groups. Do not assume that what applies for one group (e.g., you and other people living on income Level 4 or unconscious soldiers) applies for another (e.g., people not living on income Level 4 or sleeping babies). Beware of “the majority.” The majority just means more than half. Ask whether it means 51 percent, 99 percent, or something in between. Beware of vivid examples. Vivid images are easier to recall but they might be the exception rather than the rule. Assume people are not idiots. When something looks strange, be curious and humble, and think, In what way is this a smart solution?

Factfulness - Rosling's instinctual mental errors - Gap, Negativity, Straight Line

I'm doing this and a few subsequent posts for my own benefit - making brief clips from the Rosling "Factfullness" book described in the previous post to encapsulate what he calls our 10 'basic instincts' - instinctual mental errors that we make - hoping this exercise will imprint them in my feeble memory and make me less likely to perform some of the errors he describes. The next post in this series is here.

The Gap Instinct (Chapter 1) - the irresistible temptation we have to divide all kinds of things into two distinct and often conflicting groups, with an imagined gap—a huge chasm of injustice—in between (as in rich vs. poor, us vs. them). The reality is often not polarized at all. Usually the majority is right there in the middle, where the gap is supposed to be. To control the gap instinct, look for the majority.

The Negativity Instinct (Chapter 2) - ...information about bad events is much more likely to reach us. When things are getting better we often don’t hear about them, gradual improvement is not news. This gives us a systematically too-negative impression of the world around us, which is very stressful. To control the negativity instinct, expect bad news. More bad news is sometimes due to better surveillance of suffering, not a worsening world. Beware of rosy pasts. People often glorify their early experiences, and nations often glorify their histories.

The Straight Line Instinct (Chapter 3) - ..straight lines are rare in reality, remember that curves come in different shapes, many trends do not follow straight lines but are S-bends, slides, humps, or doubling lines. Not child ever kept up the rate of growth it achieved in its first six months, and no parents would expect it to. World population will be stabilizing in the next 50-100 years as birth and death rates become equal. 

Factfulness - Hans Rosling - Introduction

I have just had a read through the book “Factfulness” written by Hans Rosling together with his son and daughter, published in early 2018, very much in the vein of Pinker’s “Enlightenment Now” published at roughly the same time. Both books provided detailed data showing that things in this world are not as bad as we commonly suppose. I abstracted portions of Pinker's book in a series of MindBlog posts beginning on 3/1/18,  and in a series of subsequent posts  I want  to pass on my thumbnail sketches, taken from the text, of the main points of the "Factfulness" book. They are descriptions of 10 human "instincts", evolved psychological short cuts that blind us to obvious facts that are revealed by just paying attention to the numbers. The next post in this series is here.

To begin, however, this post points to a marvellous video that serves as an introduction  - Hans Rosling's 200 Countries, 200 Years, 4 Minutes - The Joy of Stats - from BBC 4:

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).

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.

Highlights

•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

Summary

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.

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 stress...it 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.

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.

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.:

Significance

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.

Abstract

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.

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.

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.

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.

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).

"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.

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.