YouTube algorithms do not appear to drive attention to radical content.

From Hosseinmardi et al.;  

Significance

Daily share of news consumption on YouTube, a social media platform with more than 2 billion monthly users, has increased in the last few years. Constructing a large dataset of users’ trajectories across the full political spectrum during 2016–2019, we identify several distinct communities of news consumers, including “far-right” and “anti-woke.” Far right is small and not increasing in size over the observation period, while anti-woke is growing, and both grow in consumption per user. We find little evidence that the YouTube recommendation algorithm is driving attention to this content. Our results indicate that trends in video-based political news consumption are determined by a complicated combination of user preferences, platform features, and the supply-and-demand dynamics of the broader web.

Abstract

Although it is under-studied relative to other social media platforms, YouTube is arguably the largest and most engaging online media consumption platform in the world. Recently, YouTube’s scale has fueled concerns that YouTube users are being radicalized via a combination of biased recommendations and ostensibly apolitical “anti-woke” channels, both of which have been claimed to direct attention to radical political content. Here we test this hypothesis using a representative panel of more than 300,000 Americans and their individual-level browsing behavior, on and off YouTube, from January 2016 through December 2019. Using a labeled set of political news channels, we find that news consumption on YouTube is dominated by mainstream and largely centrist sources. Consumers of far-right content, while more engaged than average, represent a small and stable percentage of news consumers. However, consumption of “anti-woke” content, defined in terms of its opposition to progressive intellectual and political agendas, grew steadily in popularity and is correlated with consumption of far-right content off-platform. We find no evidence that engagement with far-right content is caused by YouTube recommendations systematically, nor do we find clear evidence that anti-woke channels serve as a gateway to the far right. Rather, consumption of political content on YouTube appears to reflect individual preferences that extend across the web as a whole.

Castration delays aging

I pass on this nugget by Beverly Purnell in the Editor's Choice section of this week's Science Magazine noting an interesting paper by Sugrue et al. First her summary, then the abstract of the Sugrue et al. paper.  

The summary:

As we age, our genetic material changes, not only through DNA mutation but also by epigenetic modification. Indeed, chronological age can be estimated based on analysis of DNA methylation. Male and female mammals display different average life spans, and a role for sex hormones is expected in this effect. Sugrue et al. established an epigenetic clock in sheep by examining methylated DNA in samples from blood and ears. They show that castration extends an animal's life span and feminizes the epigenome at specific androgen-regulated loci during aging.

The Abstract:

In mammals, females generally live longer than males. Nevertheless, the mechanisms underpinning sex-dependent longevity are currently unclear. Epigenetic clocks are powerful biological biomarkers capable of precisely estimating chronological age and identifying novel factors influencing the aging rate using only DNA methylation data. In this study, we developed the first epigenetic clock for domesticated sheep (Ovis aries), which can predict chronological age with a median absolute error of 5.1 months. We have discovered that castrated male sheep have a decelerated aging rate compared to intact males, mediated at least in part by the removal of androgens. Furthermore, we identified several androgen-sensitive CpG dinucleotides that become progressively hypomethylated with age in intact males, but remain stable in castrated males and females. Comparable sex-specific methylation differences in MKLN1 also exist in bat skin and a range of mouse tissues that have high androgen receptor expression, indicating that it may drive androgen-dependent hypomethylation in divergent mammalian species. In characterizing these sites, we identify biologically plausible mechanisms explaining how androgens drive male-accelerated aging.

What is our brain's spontaneous activity for?

Continuing in MindBlog's recent thread on the predictive brain (see here and here), I pass on highlights of an opinion piece by Pezzulo et al., who suggest that all that background brain noise has a very specific purpose - figuring out what to expect next:

Spontaneous brain dynamics are manifestations of top-down dynamics of generative models detached from action–perception cycles.

Generative models constantly produce top-down dynamics, but we call them expectations and attention during task engagement and spontaneous activity at rest.

Spontaneous brain dynamics during resting periods optimize generative models for future interactions by maximizing the entropy of explanations in the absence of specific data and reducing model complexity.

Low-frequency brain fluctuations during spontaneous activity reflect transitions between generic priors consisting of low-dimensional representations and connectivity patterns of the most frequent behavioral states.

High-frequency fluctuations during spontaneous activity in the hippocampus and other regions may support generative replay and model learning.

Brains at rest generate dynamical activity that is highly structured in space and time. We suggest that spontaneous activity, as in rest or dreaming, underlies top-down dynamics of generative models. During active tasks, generative models provide top-down predictive signals for perception, cognition, and action. When the brain is at rest and stimuli are weak or absent, top-down dynamics optimize the generative models for future interactions by maximizing the entropy of explanations and minimizing model complexity. Spontaneous fluctuations of correlated activity within and across brain regions may reflect transitions between ‘generic priors’ of the generative model: low dimensional latent variables and connectivity patterns of the most common perceptual, motor, cognitive, and interoceptive states. Even at rest, brains are proactive and predictive.

The connections between two brain regions that are required for consciousness are regulated by dopamine.

Important work from Spindler et al.:  

Significance

Understanding the neural bases of consciousness is of basic scientific and clinical importance. Human neuroimaging has established that a network of interconnected brain regions known as the default mode network disintegrates in anesthesia and after brain damage that causes disorders of consciousness. However, the neurochemical underpinnings of this network change remain largely unknown. Motivated by preclinical animal work and clinical observations, we found that across pharmacological (sedation) and pathological (disorders of consciousness) consciousness perturbation, the dopaminergic source nucleus, the ventral tegmental area, disconnects from the main nodes of the default mode network. As the severity of this dopaminergic disconnection was associated with default mode network disintegration, we propose that dopaminergic modulation may be a central mechanism for consciousness maintenance.

Abstract

Clinical research into consciousness has long focused on cortical macroscopic networks and their disruption in pathological or pharmacological consciousness perturbation. Despite demonstrating diagnostic utility in disorders of consciousness (DoC) and monitoring anesthetic depth, these cortico-centric approaches have been unable to characterize which neurochemical systems may underpin consciousness alterations. Instead, preclinical experiments have long implicated the dopaminergic ventral tegmental area (VTA) in the brainstem. Despite dopaminergic agonist efficacy in DoC patients equally pointing to dopamine, the VTA has not been studied in human perturbed consciousness. To bridge this translational gap between preclinical subcortical and clinical cortico-centric perspectives, we assessed functional connectivity changes of a histologically characterized VTA using functional MRI recordings of pharmacologically (propofol sedation) and pathologically perturbed consciousness (DoC patients). Both cohorts demonstrated VTA disconnection from the precuneus and posterior cingulate (PCu/PCC), a main default mode network node widely implicated in consciousness. Strikingly, the stronger VTA–PCu/PCC connectivity was, the more the PCu/PCC functional connectome resembled its awake configuration, suggesting a possible neuromodulatory relationship. VTA-PCu/PCC connectivity increased toward healthy control levels only in DoC patients who behaviorally improved at follow-up assessment. To test whether VTA–PCu/PCC connectivity can be affected by a dopaminergic agonist, we demonstrated in a separate set of traumatic brain injury patients without DoC that methylphenidate significantly increased this connectivity. Together, our results characterize an in vivo dopaminergic connectivity deficit common to reversible and chronic consciousness perturbation. This noninvasive assessment of the dopaminergic system bridges preclinical and clinical work, associating dopaminergic VTA function with macroscopic network alterations, thereby elucidating a critical aspect of brainstem–cortical interplay for consciousness.

How the insiders win - Philanthropy, advocacy, and profit.

From Bertrand et al., a study showing how U.S. Federal rulemaking based on considering "independent viewpoints" is corrupted:

Information is central to designing effective policy, and policymakers often rely on competing interests to separate useful from biased information. We show how this logic of virtuous competition can break down, using a new and comprehensive dataset on U.S. federal regulatory rulemaking for 2003–2016. For-profit corporations and nonprofit entities are active in the rulemaking process and are arguably expected to provide independent viewpoints. Policymakers, however, may not be fully aware of the financial ties between some firms and nonprofits – grants that are legal and tax-exempt, but hard to trace. We document three patterns which suggest that these grants may distort policy. First, we show that, shortly after a firm donates to a nonprofit, that nonprofit is more likely to comment on rules on which the firm has also commented. Second, when a firm comments on a rule, the comments by nonprofits that recently received grants from the firm’s foundation are systematically closer in content to the firm’s own comments, relative to comments submitted by other nonprofits. Third, the final rule’s discussion by a regulator is more similar to the firm’s comments on that rule when the firm’s recent grantees also commented on it.

Electromagnetic radiation in the wireless signal range increases wakefulness in mice

Liu et al. (open source) find that electromagnetic radiation (EMR) in the wireless signal range used by our cell phones, laptops, and Wi-Fi routers can increase wakefulness in mice, but only if the signal is pulsed and at much higher levels than are present in our homes.  

Significance

The steady increase of electromagnetic radiation (EMR) in the environment, particularly the wireless signal, causes serious public concern over its potential negative impact on health. However, it is challenging to examine such impact on human subjects due to associated complex issues. In this study, we establish an experimental system for the investigation of EMR impact on mice. Using this system, we uncovered a causal relationship between 2.4-GHz EMR modulated by 100-Hz square pulses and increased wakefulness in mice. This result identifies sleep alteration as a potential consequence of exposure to excessive wireless signals.

Abstract

Electromagnetic radiation (EMR) in the environment has increased sharply in recent decades. The effect of environmental EMR on living organisms remains poorly characterized. Here, we report the impact of wireless-range EMR on the sleep architecture of mouse. Prolonged exposure to 2.4-GHz EMR modulated by 100-Hz square pulses at a nonthermal output level results in markedly increased time of wakefulness in mice. These mice display corresponding decreased time of nonrapid eye movement (NREM) and rapid eye movement (REM). In contrast, prolonged exposure to unmodulated 2.4-GHz EMR at the same time-averaged output level has little impact on mouse sleep. These observations identify alteration of sleep architecture in mice as a specific physiological response to prolonged wireless-range EMR exposure.

The final two paragraphs of the paper make clear that the effects on mouse sleep require much higher power densities for the 2.4-GHz EMR signals than are emitted by smartphones, laptops, or Wi-Fi routers.

....the average power density at close proximity is about 0.037 W/m2 for a smartphone, 0.013 W/m2 for a laptop, and 0.13 W/m2 near the Wi-Fi router (1). These values are considerably lower than the time- and whole-body–averaged general public exposure limit of 10 W/m2 or occupational exposure limit of 50 W/m2 for 2–300 GHz suggested by International Commission on Non-Ionizing Radiation Protection (43). In our experiments, the measured spatial averaged power density for Conti8W is 36.80 ± 0.92 W/m2. Pulse64W is expected to have the same power density. Importantly, the effective EMR dose for inducing a biological response in mice is likely to be different from that in humans. Therefore, the relatively high EMR dose of the Pulse64W regimen that causes increased wakefulness in mice could be markedly reduced in humans. An epidemiological survey among those who work under either very high or very low doses of wireless radiation may reveal some clues.

In this study, 2.4-GHz EMR is modulated by 100-Hz square pulses, which have sharp edges and thus might have some unanticipated impact on neural activity in the brain. Additional experiments should be performed to examine whether other modulation functions such as sinusoidal modulation can induce similar increase of wakefulness in mice. In addition, other modulation frequencies such as 10 and 1,000 Hz should be investigated to answer the question of whether increased wakefulness is specific to certain modulation frequencies. Finally, both the intensity and the frequency of the carrier EMR (2.4 GHz in this study) should be scrutinized.

Seeing others react to threats triggers our own internal threat responses.

From Haaker et al. (open source): 

Significance

Social transmission of threat information by observation is effective in humans and other animals. However, it is unknown if such observation of others’ reacting to threats can retrieve memories that have been previously learned through direct, firsthand aversive experiences. Here, we show concordantly in humans and rats that observing a conspecific’s reactions to a threat is sufficient to recover associative memories of direct, firsthand aversive experiences, measured as conditioned threat responses (physiological responses and defensive behavior) in the observer. The reinstatement of threat responses by observation of others is specific to the context that is observed as being dangerous. Our findings provide cross-species evidence that observation of others’ threat reactions can recover associative memories of direct, firsthand aversive experiences.

Abstract

Information about dangers can spread effectively by observation of others’ threat responses. Yet, it is unclear if such observational threat information interacts with associative memories that are shaped by the individual’s direct, firsthand experiences. Here, we show in humans and rats that the mere observation of a conspecific’s threat reactions reinstates previously learned and extinguished threat responses in the observer. In two experiments, human participants displayed elevated physiological responses to threat-conditioned cues after observational reinstatement in a context-specific manner. The elevation of physiological responses (arousal) was further specific to the context that was observed as dangerous. An analogous experiment in rats provided converging results by demonstrating reinstatement of defensive behavior after observing another rat’s threat reactions. Taken together, our findings provide cross-species evidence that observation of others’ threat reactions can recover associations previously shaped by direct, firsthand aversive experiences. Our study offers a perspective on how retrieval of threat memories draws from associative mechanisms that might underlie both observations of others’ and firsthand experiences.

Historical language records reveal societal depression and anxiety in past two decades higher than during 20th century.

Fascinating work from Bollen et al. (open source):  

Significance

Can entire societies become more or less depressed over time? Here, we look for the historical traces of cognitive distortions, thinking patterns that are strongly associated with internalizing disorders such as depression and anxiety, in millions of books published over the course of the last two centuries in English, Spanish, and German. We find a pronounced “hockey stick” pattern: Over the past two decades the textual analogs of cognitive distortions surged well above historical levels, including those of World War I and II, after declining or stabilizing for most of the 20th century. Our results point to the possibility that recent socioeconomic changes, new technology, and social media are associated with a surge of cognitive distortions.

Abstract

Individuals with depression are prone to maladaptive patterns of thinking, known as cognitive distortions, whereby they think about themselves, the world, and the future in overly negative and inaccurate ways. These distortions are associated with marked changes in an individual’s mood, behavior, and language. We hypothesize that societies can undergo similar changes in their collective psychology that are reflected in historical records of language use. Here, we investigate the prevalence of textual markers of cognitive distortions in over 14 million books for the past 125 y and observe a surge of their prevalence since the 1980s, to levels exceeding those of the Great Depression and both World Wars. This pattern does not seem to be driven by changes in word meaning, publishing and writing standards, or the Google Books sample. Our results suggest a recent societal shift toward language associated with cognitive distortions and internalizing disorders.

Our gut microbiome pattern reflects healthy aging and survival

Interesting analysis by Wilmanski et al.:

The gut microbiome has important effects on human health, yet its importance in human ageing remains unclear. In the present study, we demonstrate that, starting in mid-to-late adulthood, gut microbiomes become increasingly unique to individuals with age. We leverage three independent cohorts comprising over 9,000 individuals and find that compositional uniqueness is strongly associated with microbially produced amino acid derivatives circulating in the bloodstream. In older age (over ~80 years), healthy individuals show continued microbial drift towards a unique compositional state, whereas this drift is absent in less healthy individuals. The identified microbiome pattern of healthy ageing is characterized by a depletion of core genera found across most humans, primarily Bacteroides. Retaining a high Bacteroides dominance into older age, or having a low gut microbiome uniqueness measure, predicts decreased survival in a 4-year follow-up. Our analysis identifies increasing compositional uniqueness of the gut microbiome as a component of healthy ageing, which is characterized by distinct microbial metabolic outputs in the blood.

How our brain cortex changes in the transition from childhood to adolescence.

This open source article from Dong et al. has some excellent summary graphics:  

Significance

Here, we describe age-dependent shifts in the macroscale organization of cortex in childhood and adolescence. The characterization of functional connectivity patterns in children revealed an overarching organizational framework anchored within the unimodal cortex, between somatosensory/motor and visual regions. Conversely, in adolescents, we observed a transition into an adult-like gradient, situating the default network at the opposite end of a spectrum from primary somatosensory/motor regions. This spatial framework emerged gradually with age, reaching a sharp inflection point at the transition from childhood to adolescence. These data reveal a developmental change from a functional motif first dominated by the distinction between sensory and motor systems and then balanced through interactions with later-maturing aspects of association cortex that support more abstract cognitive functions.

Abstract

The transition from childhood to adolescence is marked by pronounced shifts in brain structure and function that coincide with the development of physical, cognitive, and social abilities. Prior work in adult populations has characterized the topographical organization of the cortex, revealing macroscale functional gradients that extend from unimodal (somatosensory/motor and visual) regions through the cortical association areas that underpin complex cognition in humans. However, the presence of these core functional gradients across development as well as their maturational course have yet to be established. Here, leveraging 378 resting-state functional MRI scans from 190 healthy individuals aged 6 to 17 y old, we demonstrate that the transition from childhood to adolescence is reflected in the gradual maturation of gradient patterns across the cortical sheet. In children, the overarching organizational gradient is anchored within the unimodal cortex, between somatosensory/motor and visual territories. Conversely, in adolescence, the principal gradient of connectivity transitions into an adult-like spatial framework, with the default network at the opposite end of a spectrum from primary sensory and motor regions. The observed gradient transitions are gradually refined with age, reaching a sharp inflection point in 13 and 14 y olds. Functional maturation was nonuniformly distributed across cortical networks. Unimodal networks reached their mature positions early in development, while association regions, in particular the medial prefrontal cortex, reached a later peak during adolescence. These data reveal age-dependent changes in the macroscale organization of the cortex and suggest the scheduled maturation of functional gradient patterns may be critically important for understanding how cognitive and behavioral capabilities are refined across development.

Graphic depictions of an integrative model of mind

To hopefully enhance the chance that you will pay attention to the creative and seminal thinking in the open source Laukkonen and Slagter review article whose abstract I passed on in my July 21 post,  I now pass on their striking concluding statement and then  two graphics whose legends summarize the main ideas presented. I think this work offers a plausible and appealing integration of neuroscience and meditative traditions.  

We have taken on the daunting task of providing a theory for understanding the effects of meditation within the predictive processing framework. Contemplative science is a young field and predictive processing is a new theory, although both have roots going much farther back. All theories are subject to change, but perhaps particularly so for such new domains of enquiry. Nevertheless, we think the conditions are suitable for a more overarching theory that may also thwart further siloing and fragmentation of scientific research, as has been commonplace among the mind-sciences. A strength of our framework is its simplicity: Being in the here and now reduces predictive processing. And yet, this basic idea can explain how each meditation technique uniquely deconstructs the minds tendency to project the past onto the present, how certain insights may arise, the nature of hierarchical self-processing, and the plasticity of the human mind. There is scope here, we think, to eventually reveal what makes a meditator an expert, why meditation has such broad clinical effects, and how we might begin mitigating some of the negative consequences of meditation. Last but not least, our framework seems to bring ancient Eastern and modern scientific ideas closer together, showing how the notion of conditioned experience in Buddhism aligns with the notion of the experience-dependent predictive brain.

Fig. 1. Here we use the Pythagoras Tree to provide an intuitive illustration of how organisms represent the world with increasing counterfactual depth or abstraction. The tree is constructed using squares that are scaled down by the square root of 2 divided by 2 and placed such that the corners of the squares meet and form a triangle between them, recursively. Analogously, the brain constructs experience from temporally precise and unimodal models of present-moment sensory representations and input (e.g., pixels on a screen), into ever more abstract, transmodal, and temporally deep models (e.g., a theory paper). Meditation brings one increasingly into the present moment, thus reducing the tendency to conceptualize away from the here and now, akin to observing the pixels rather than the words. This reduction of conceptualization ought to also have profound effects on the sense of self, which also relies on abstract model building, and ultimately is said to reveal an underlying seemingly “unconditioned” state of consciousness as such (like the white background underlying the pixels).

 

Fig. 2. In this schematic we illustrate two aspects of the many-to-(n)one model. The first and most foundational proposal is that meditation gradually flattens the predictive hierarchy or ‘prunes the counterfactual tree’, by bringing the meditator into the here and now, illustrated in the left figure. Thus, meditative depth is defined by the extent that the organism is not constructing temporally thick predictions. In the right figure, we dissect the predictive hierarchy into three broad levels. We propose that thinking (and therefore the narrative self [NS]) sits at the top of the predictive hierarchy (Carhart-Harris and Friston, 2010, 2019). Sensing and perceiving and therefore the embodied experiencing self [ES] sits below it (Gallagher, 2000; Seth, 2013). Finally, a basal form of self-hood characterized by the subject-object [S/O] duality sits at the earliest level. FA brings the practitioner out of the narrative self and into a more experiencing and embodied mode of being. Then, through dereification from present moment experience (including bodily sensations) OM brings the practitioner more into a state where contents of experience are treated equally, and one is able to experience non-judgmentally (sensing without appraisal), but even in very advanced states, a subject-object duality remains. During OM, certain epistemic discoveries or insights about the nature and behavior of generative models may occur. Finally, through ND practices the subject-object distinction may fall away and the background or “groundless ground” of all experience—awareness itself—can be uncovered. Another way to characterize this process is as follows: FA employs regular (conditional) attention to an object of sensing, OM employs bare (unconditional) attention, and ND practice employs reflexive awareness that permits the non-dual witnessing of the subject-object dichotomy and finally pure or non-dual awareness by releasing attention altogether.

 

 

Stable individual differences in infants’ responses to violations of intuitive physics

Interesting observations by Perez and Feigenson:

Infants look longer at impossible or unlikely events than at possible events. While these responses to expectancy violations have been critical for understanding early cognition, interpreting them is challenging because infants’ responses are highly variable. This variability has been treated as an unavoidable nuisance inherent to infant research. Here we asked whether the variability contains signal in addition to noise: namely, whether some infants show consistently stronger responses to expectancy violations than others. Infants watched two unrelated physical events 6 mo apart; these events culminated in either an impossible or an expected outcome. We found that infants who exhibited the strongest looking response to an impossible event at 11 mo also exhibited the strongest response to an entirely different impossible event at 17 mo. Furthermore, violation-of-expectation responses in infancy predicted children’s explanation-based curiosity at 3 y old. In contrast, there was no longitudinal relation between infants’ responses to events with expected outcomes at 11 and 17 mo, nor any link with later curiosity; hence, infants’ responses do not merely reflect individual differences in attention but are specific to expectancy violations. Some children are better than others at detecting prediction errors—a trait that may be linked to later cognitive abilities.

A place in the brain for the sense of ‘self’

Fascinating observations from Parvizi et al, whose findings provide a causal link between the right anterior and dorsal posteromedial cortex (PMC) and the sense of self and provide unique clues about the pathophysiology of self-dissociation in neuropsychiatric conditions. Their abstract:

The posteromedial cortex (PMC) is known to be a core node of the default mode network. Given its anatomical location and blood supply pattern, the effects of targeted disruption of this part of the brain are largely unknown. Here, we report a rare case of a patient (S19_137) with confirmed seizures originating within the PMC. Intracranial recordings confirmed the onset of seizures in the right dorsal posterior cingulate cortex, adjacent to the marginal sulcus, likely corresponding to Brodmann area 31. Upon the onset of seizures, the patient reported a reproducible sense of self-dissociation—a condition he described as a distorted awareness of the position of his body in space and feeling as if he had temporarily become an outside observer to his own thoughts, his “me” having become a separate entity that was listening to different parts of his brain speak to each other. Importantly, 50-Hz electrical stimulation of the seizure zone and a homotopical region within the contralateral PMC induced a subjectively similar state, reproducibly. We supplement our clinical findings with the definition of the patient’s network anatomy at sites of interest using cortico-cortical–evoked potentials, experimental and resting-state electrophysiological connectivity, and individual-level functional imaging. This rare case of patient S19_137 highlights the potential causal importance of the PMC for integrating self-referential information and provides clues for future mechanistic studies of self-dissociation in neuropsychiatric populations.

From many to (n)one: Meditation and the plasticity of the predictive mind

I had a chat with my former University of Wisconsin colleague Richard Davidson during my visit to Madison, WI last week, and he pointed me to an excellent open source review article by Laukkonen and Slagter, From many to (n)one: Meditation and the plasticity of the predictive mind. They offer an integrated predictive processing account of three main styles of meditation. I just finished reading through their lucid account and plan to carefully re-read it several times. I pass on the summary points and abstract: 

Highlights

• Predictive processing provides a novel theoretical window on meditation. 

• Deconstructive meditations progressively reduce temporally deep processing. 

• Insight experiences arise during meditation due to Bayesian model reduction 

• Meditation deconstructs self models by reducing abstract processing. 

• Non-dual awareness or pure consciousness is the ‘here and now’.

Abstract

How profoundly can humans change their own minds? In this paper we offer a unifying account of deconstructive meditation under the predictive processing view. We start from simple axioms. First, the brain makes predictions based on past experience, both phylogenetic and ontogenetic. Second, deconstructive meditation brings one closer to the here and now by disengaging anticipatory processes. We propose that practicing meditation therefore gradually reduces counterfactual temporally deep cognition, until all conceptual processing falls away, unveiling a state of pure awareness. Our account also places three main styles of meditation (focused attention, open monitoring, and non-dual) on a single continuum, where each technique relinquishes increasingly engrained habits of prediction, including the predicted self. This deconstruction can also permit certain insights by making the above processes available to introspection. Our framework is consistent with the state of empirical and (neuro)phenomenological evidence and illuminates the top-down plasticity of the predictive mind. Experimental rigor, neurophenomenology, and no-report paradigms are needed to further understanding of how meditation affects predictive processing and the self.

Psilocybin induces rapid and persistent growth of dendritic spines in frontal cortex in vivo

Interesting results from Shao et al.: 

 Highlights

• Psilocybin ameliorates stress-related behavioral deficit in mice 

• Psilocybin increases spine density and spine size in frontal cortical pyramidal cells 

• Psilocybin-evoked structural remodeling is persistent for at least 1 month 

• The dendritic rewiring is accompanied by elevated excitatory neurotransmission

Summary

Psilocybin is a serotonergic psychedelic with untapped therapeutic potential. There are hints that the use of psychedelics can produce neural adaptations, although the extent and timescale of the impact in a mammalian brain are unknown. In this study, we used chronic two-photon microscopy to image longitudinally the apical dendritic spines of layer 5 pyramidal neurons in the mouse medial frontal cortex. We found that a single dose of psilocybin led to ∼10% increases in spine size and density, driven by an elevated spine formation rate. The structural remodeling occurred quickly within 24 h and was persistent 1 month later. Psilocybin also ameliorated stress-related behavioral deficit and elevated excitatory neurotransmission. Overall, the results demonstrate that psilocybin-evoked synaptic rewiring in the cortex is fast and enduring, potentially providing a structural trace for long-term integration of experiences and lasting beneficial actions.

Graphical Abstract:

Albert Einstein Quotes

I am sending on some juicy Albert Einstein quotes posted by one of the members of the Madison Wisconsin book group that I still belong to...

 

“I didn't arrive at my understanding of the fundamental laws of the universe through my rational mind.”

 

“Concerning matter, we have been all wrong. What we have called matter is energy, whose vibration has been so lowered as to be perceptible to the senses. Matter is spirit reduced to point of visibility. There is no matter.”

 

"Time and space are not conditions in which we live, but modes by which we think. Physical concepts are free creations of the human mind, and are not, however it may seem, determined by the external world."

 

“Time does not exist – we invented it. Time is what the clock says. The distinction between the past, present and future is only a stubbornly persistent illusion.”

 

“I think 99 times and find nothing. I stop thinking, swim in silence, and the truth comes to me."

 

"The intellect has little to do on the road to discovery. There comes a leap in consciousness, call it intuition or what you will, the solution comes to you and you don’t know how or why.”

 

"A human being experiences himself, his thoughts and feelings as something separated from the rest, a kind of optical delusion of consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest to us. Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty."

 

"Our separation from each other is an optical illusion."

 

“When something vibrates, the electrons of the entire universe resonate with it. Everything is connected. The greatest tragedy of human existence is the illusion of separateness.”

 

“Reality is merely an illusion, albeit a very persistent one.”

 

“We are souls dressed up in sacred biochemical garments and our bodies are the instruments through which our souls play their music.”

 

“When you examine the lives of the most influential people who have ever walked among us, you discover one thread that winds through them all. They have been aligned first with their spiritual nature and only then with their physical selves.”

 

“The true value of a human being can be found in the degree to which he has attained liberation from the self.”

 

“The ancients knew something, which we seem to have forgotten.”

 

“The more I learn of physics, the more I am drawn to metaphysics.”

 

“One thing I have learned in a long life: that all our science, measured against reality, is primitive and childlike. We still do not know one thousandth of one percent of what nature has revealed to us. It is entirely possible that behind the perception of our senses, worlds are hidden of which we are unaware.”

 

“I’m not an atheist. The problem involved is too vast for our limited minds. We are in the position of a little child entering a huge library filled with books in many languages. The child knows someone must have written those books.”

 

"The common idea that I am an atheist is based on a big mistake. Anyone who interprets my scientific theories this way, did not understand them."

 

"Everything is determined, every beginning and ending, by forces over which we have no control. It is determined for the insect, as well as for the star. Human beings, vegetables, or cosmic dust, we all dance to a mysterious tune, intoned in the distance by an invisible piper."

 

“The religion of the future will be a cosmic religion. It will transcend a personal God and avoid dogma and theology.”

 

“Energy cannot be created or destroyed, it can only be changed from one form to another.”

 

“Everything is energy and that is all there is to it. Match the frequency of the reality you want and you can not help but get that reality. It can be no other way. This is not philosophy. This is physics.”

 

"I am happy because I want nothing from anyone. I do not care about money. Decorations, titles or distinctions mean nothing to me. I do not crave praise. I claim credit for nothing. A happy man is too satisfied with the present to dwell too much on the future."

 

Evolutionary models of financial markets.

Levin and Lo's introduction of a PNAS special issue on evolutionary models of financial markets is an interesting read. A few clips:

The brilliant evolutionary insights of Darwin and others have revolutionized our understanding of the world. Darwin was impressed by the “tangled bank” of elaborate forms that emerged from the undirected processes of evolution to produce the complexity of the biological world. Through continuous innovation coupled with the deceptively simple filter known as natural selection, the characteristics of species and their interactions change in response to changing environments. However, evolution is not limited only to the biological world. Wherever the evolutionary forces of reproduction, variation, and selection exist—as they do in financial markets—evolutionary consequences will follow. There are of course major differences as well between the nature of the evolutionary process in ecological and economic contexts, largely influenced by the relative importance of top-down control, and the degree to which predictive models and long-term planning can be invoked. These are, however, differences of degree.

There are profound similarities between financial systems and the biosphere. Both are complex adaptive systems in which individual agents act to enhance their own interests and objectives, leading to self-organization and emergent features. In viewing global financial markets as comprising a complex-adaptive biological system, researchers in this area intend to develop more effective models to understand these systems. This is not only of theoretical interest, but also has the practical aim to promote economic growth while maintaining financial stability, with the ultimate goal of allocating resources more efficiently through better financial methods.

Evolution is about short-term, relative optimality with respect to other participants in the system. In the biosphere, natural selection acts to improve reproductive success relative to the benchmark of other genomes, within and across species. Evolutionary change can thus be thought of in terms of differential fitness: that is, small differences in reproductive rates between individuals over time leading to large differences in populations. Even the very mechanisms of evolution—including those that generate new variation—are subject to constant modification. In the financial world, the evolutionary forces of mutation, recombination, reproduction, and selection often work on financial institutions and market participants through direct competition, finance “red in tooth and claw.” Financial concepts and strategies thus reproduce themselves through cultural transmission and adoption based on their success in the marketplace. These strategies undergo variation through financial innovation, analogous to mutation or genetic recombination in a biological system, but take place at the level of information and abstract thought in financial contexts. It is “survival of the richest.”

The evolutionary lens provides a natural way to introduce biological concepts into financial and economic analysis. As the evolutionary biologist Theodosius Dobzhansky said, “Nothing in biology makes sense except in the light of evolution” (5). The same may hold for the financial world. Phenomena that have been difficult to analyze within a traditional economic framework, such as growth, size, scale, self-organization, the lifecycle of products and industries, bull/bear market cycles, and the rate of variation or innovation within a system, are all subject to evolutionary forces, whether they take place in the Petri dish or on the trading floor. Biological experiments thus may be able to directly inform economic insights, and market behavior may be able to shed light on evolutionary mysteries in the biological world.

The A.I. Revolution, Trillionaires and the Future of Political Power.

I want to point to a fascinating Ezra Klein podcast - you can read the transcript here - that is an interview with Sam Altman, the C.E.O. of OpenAI, which is one of the biggest and most interesting of the companies trying to create general purpose artificial intelligence. His recent essay titled "Moore's Law for Everything" has received wide comment, and it's topics are the focus of the interview. Klein notes: "what caught my eye about this essay, “Moore’s Law for Everything,” is Altman’s effort to try and imagine the political consequences of true artificial intelligence and the policies that could decide whether it ushers in utopia or dystopia." I'm going to pass on only clips from Klein's general introductions to give you a taste of the direction of the arguments, and urge you to read both the transcript of the podcast and Altman's essay.

“The technological progress we make in the next 100 years will be far larger than all we’ve made since we first controlled fire and invented the wheel...This revolution will generate enough wealth for everyone to have what they need, if we as a society manage it responsibly.”...Altman's argument is this: Since the 1970s, computers have gotten exponentially better even as they’re gotten cheaper, a phenomenon known as Moore’s Law. Altman believes that A.I. could get us closer to Moore’s Law for everything: it could make everything better even as it makes it cheaper. Housing, health care, education, you name it.

A.I. will create phenomenal wealth, but it will do so by driving the price of a lot of labor to basically zero. That is how everything gets cheaper. It’s also how a lot of people lose their jobs...To make that world a good world for people, to make that a utopia rather than a dystopia, it requires really radical policy change to make sure the wealth A.I. creates is distributed broadly. But if we can do that, he says, well, then we can improve the standard of living for people more than we ever have before in less time. So Altman’s got some proposals here for how we can do that. They’re largely proposals to tax wealth and land. And I push on them here.

This is a conversation, then, about the political economy of the next technological age. Some of it is speculative, of course, but some of it isn’t. That shift of power and wealth is already underway. Altman is proposing an answer: a move toward taxing land and wealth, and distributing it to all. We talk about that idea, but also the political economy behind it: Are the people gaining all this power and wealth really going to offer themselves up for more taxation? Or will they fight it tooth-and-nail?

We also discuss who is funding the A.I. revolution, the business models these systems will use (and the dangers of those business models), how A.I. would change the geopolitical balance of power, whether we should allow trillionaires, why the political debate over A.I. is stuck, why a pro-technology progressivism would also need to be committed to a radical politics of equality, what global governance of A.I. could look like, whether I’m just “energy flowing through a neural network,” and much more.

(You can also listen to the whole conversation by following “The Ezra Klein Show” on Apple, Spotify, Google or wherever you get your podcasts.)

Watching a brain encode present, past, and future….

We all exist as an ongoing simulation of past, present, and future in our brains, with the hallucination we take to be reality being perturbed only when our brains’ expectations are not met. Dotson and Yartsev do experiments in flying bats (of a sort not permitted in humans) that record from the hippocampus showing patterns of neuron activity of the sort needed to support this process. They find that this activity not only encodes the bat’s present location but also signals its positions in the past and future. The technology involved in doing the brain implants that record and wirelessly transmit the neuronal activity, as well as the sophisticated data analysis, is truly awesome (One has to download a massive technical supplement, much too large to include in the article, to get the details.) Here I pass on only the editor’s summary and the abstract for the article:  

Representing space in past and future

As an organism moves through space, its brain has to remember its most recent location and anticipate its future position, not just its current place in the world. Earlier studies reported so-called retrospective and prospective place coding in rats while they were running along linear tracks. However, it would be advantageous to study an animal that rapidly moves through three-dimensional space with high precision. Dotson and Yartsev recorded from flying bats to investigate whether place cell activity in hippocampus area CA1 represents local (current) or nonlocal positions. They discovered that the hippocampus not only encodes the bat's present location but also signals its positions in the past and future.

Abstract

Navigation occurs through a continuum of space and time. The hippocampus is known to encode the immediate position of moving animals. However, active navigation, especially at high speeds, may require representing navigational information beyond the present moment. Using wireless electrophysiological recordings in freely flying bats, we demonstrate that neural activity in area CA1 predominantly encodes nonlocal spatial information up to meters away from the bat’s present position. This spatiotemporal representation extends both forward and backward in time, with an emphasis on future locations, and is found during both random exploration and goal-directed navigation. The representation of position thus extends along a continuum, with each moment containing information about past, present, and future, and may provide a key mechanism for navigating along self-selected and remembered paths.

Sullivan on what has happened to the belief system of the American elites.

In a strident essay Andrew Sullivan pushes back against his critics who troll him as being a far rightist. He deflects the critique by charging that the belief system of the Democratic progressive American elites has moved much farther to the left than the Republicans have moved to the right. Some clips:

Take a big step back. Observe what has happened in our discourse since around 2015...What is it? It is, I’d argue, the sudden, rapid, stunning shift in the belief system of the American elites. It has sent the whole society into a profound cultural dislocation. It is, in essence, an ongoing moral panic against the specter of “white supremacy,” which is now bizarrely regarded as an accurate description of the largest, freest, most successful multiracial democracy in human history...The elites, increasingly sequestered within one political party and one media monoculture, educated by colleges and private schools that have become hermetically sealed against any non-left dissent, have had a “social justice reckoning” these past few years.

..the core point of that movement, its essential point, is that liberalism is no longer enough. Not just not enough, but itself a means to perpetuate “white supremacy,” designed to oppress, harm and terrorize minorities and women, and in dire need of dismantling. That’s a huge deal. And it explains a lot.

The reason “critical race theory” is a decent approximation for this new orthodoxy is that it was precisely this exasperation with liberalism’s seeming inability to end racial inequality in a generation that prompted Derrick Bell et al. to come up with the term in the first place, and Kimberlé Crenshaw to subsequently universalize it beyond race to every other possible dimension of human identity (“intersectionality”)...A specter of invisible and unfalsifiable “systems” and “structures” and “internal biases” arrived to hover over the world. Some of this critique was specific and helpful: the legacy of redlining, the depth of the wealth gap. But much was tendentious post-modern theorizing.

The movement is much broader than race — as anyone who is dealing with matters of sex and gender will tell you. The best moniker I’ve read to describe this mishmash of postmodern thought and therapy culture ascendant among liberal white elites is Wesley Yang’s coinage: “the successor ideology.”...to describe a hegemony that is saturated with “anti-Blackness,” misogyny, and transphobia, in a miasma of social “cis-heteronormative patriarchal white supremacy.” And the term “successor ideology” works because it centers the fact that this ideology wishes, first and foremost, to repeal and succeed a liberal society and democracy...Liberalism leaves you alone. The successor ideology will never let go of you. Liberalism is only concerned with your actions. The successor ideology is concerned with your mind, your psyche, and the deepest recesses of your soul. Liberalism will let you do your job, and let you keep your politics private. S.I. will force you into a struggle session as a condition for employment.

A plank of successor ideology, for example, is that the only and exclusive reason for racial inequality is “white supremacy.” Culture, economics, poverty, criminality, family structure: all are irrelevant, unless seen as mere emanations of white control. Even discussing these complicated factors is racist...The proponents of the successor ideology are] not trying to be malicious, but they are trying to basically annihilate a lot of the foundational processes that we depend upon and then remake them anew. You operate from the starting point that all the previous ideologies, methods, and processes are untrustworthy, because they produced this outcome previously, so we’ve got to remake all of them. Precisely. This is a revolution against liberalism commanded from above.

Due process? If you’re a male on campus, gone. Privacy? Stripped away — by anonymous rape accusations, exposure of private emails, violence against people’s private homes, screaming at folks in restaurants, sordid exposés of sexual encounters, eagerly published by woke mags. Non-violence? Exceptions are available if you want to “punch a fascist.” Free speech? Only if you don’t mind being fired and ostracized as a righteous consequence. Free association? You’ve got to be kidding. Religious freedom? Illegitimate bigotry. Equality? Only group equity counts now, and individuals of the wrong identity can and must be discriminated against. Color-blindness? Another word for racism. Mercy? Not for oppressors. Intent? Irrelevant. Objectivity? A racist lie. Science? A manifestation of white supremacy. Biological sex? Replaced by socially constructed gender so that women have penises and men have periods. The rule of law? Not for migrants or looters. Borders? Racist. Viewpoint diversity? A form of violence against the oppressed.

...check out Kevin Drum’s analysis of asymmetric polarization these past few decades. He shows relentlessly that over the past few decades, it’s Democrats who have veered most decisively to the extremes on policy on cultural issues since the 1990s. Not Republicans. Democrats.On immigration, Republicans have moved around five points to the right; the Democrats 35 points to the left. On abortion, Republicans who advocate a total ban have increased their numbers a couple of points since 1994; Democrats who favor legality in every instance has risen 20 points. On guns, the GOP has moved ten points right; Dems 20 points left.

It is also no accident that, as Drum notes and as David Shor has shown: “white academic theories of racism — and probably the whole woke movement in general —have turned off many moderate Black and Hispanic voters.” This is why even a huge economic boom may not be enough to keep the Democrats in power next year.

Does that mean we should support an increasingly nihilist cult on the right among the GOP? Of course not. Does it mean we should ignore its increasingly menacing contempt for electoral integrity and a stable democracy? Absolutely not. But one reason to fight for liberalism against the successor ideology is that its extremes are quite obviously fomenting and facilitating and inspiring ever-rising fanaticism in response. I fear the successor ideology’s Kulturkampf is already making the 2022 midterms a landslide for a cultish, unmoored GOP. In fighting S.I., we are also fighting Trump.

But I am not making a tactical argument here. I’m making a deeper moral argument. We can and must still fight and argue for what we believe in: a liberal democracy in a liberal society. This fight will not end if we just ignore it or allow ourselves to be intimidated by it, or join the tribal pile-ons. And I will not apologize for confronting this, however unpopular it might make me, just as I won’t apologize for confronting the poison and nihilism on the right. And if you really want to be on “the right side of liberalism,” you will join me.

Coffee is good for you, mostly....

I am dysfunctional on waking every morning until I have had a strong cup of coffee, a personal experience that makes me want to pass on Jane Brody's nice review of studies showing that drinking coffee reduces risk of all kinds of ailments, including Parkinson’s disease, melanoma, prostate cancer, even suicide.

...in numerous studies conducted throughout the world, consuming four or five eight-ounce cups of coffee (or about 400 milligrams of caffeine) a day has been associated with reduced death rates.

But,

..coffee doesn't warrant a totally clean bill of health...The most common ill effect associated with caffeinated coffee is sleep disturbance...People vary widely in how rapidly they metabolize caffeine, enabling some to sleep soundly after drinking caffeinated coffee at dinner while others have trouble sleeping if they have coffee at lunch. But even if you can fall asleep readily after an evening coffee, it may disrupt your ability to get adequate deep sleep, Mr. Pollan states in his forthcoming book, “This Is Your Mind on Plants.”

Caffeine is one of more than a thousand chemicals in coffee, not all of which are beneficial. Among others with positive effects are polyphenols and antioxidants. Polyphenols can inhibit the growth of cancer cells and lower the risk of Type 2 diabetes; antioxidants, which have anti-inflammatory effects, can counter both heart disease and cancer, the nation’s leading killers.

Some people have no "Minds Eye"

Carl Zimmer does a nice piece on the tens of millions of people who don't experience a mental camera. The condition has been named aphantasia, and millions more experience extraordinarily strong mental imagery, called hyperphantasia. British neurologist Adam Zeman estimates that 2.6 percent of people have hyperphantasia and that 0.7 percent have aphantasia...a website called the Aphantasia Network has grown into a hub for people with the condition and for researchers studying them.

The vast majority of people who report a lack of a mind’s eye have no memory of ever having had one, suggesting that they had been born without it. Yet...they had little trouble recalling things they had seen. When asked whether grass or pine tree needles are a darker shade of green, for example, they correctly answered that the needles are.

Researchers are .. starting to use brain scans to find the circuitry that gives rise to aphantasia and hyperphantasia. So far, that work suggests that mental imagery emerges from a network of brain regions that talk to each other...Decision-making regions at the front of the brain send signals to regions at the back, which normally make sense of information from the eyes. Those top-down signals can cause the visual regions to produce images that aren’t there.

In a study published in May, Dr. Zeman and his colleagues scanned the brains of 24 people with aphantasia, 25 people with hyperphantasia and 20 people with neither condition...The people with hyperphantasia had stronger activity in regions linking the front and back of the brain. They may be able to send more potent signals from decision-making regions of the front of the brain to the visual centers at the back.

Human behavior and the brain's white matter

I pass on a few edited clips from Filley's perspective piece in Science and the Editor's introduction describing work of Zhao et al.

...our cerebral cortex is only a few millimeters thick (the relative neglect of the rest of the brain below the cortex has prompted the term “corticocentric myopia”). Other regions relevant to behavior include the deep gray matter of the basal ganglia and thalamus, the brainstem and cerebellum, and the white matter that interconnects all of these structures. The white matter is composed of axonal tracts connecting different brain regions, and plays key roles in both normal brain function and a variety of neurological disorders. Zhao et al. have combined detailed magnetic resonance imaging–based assessment of brain structures with genetic data on nearly 44,000 individuals... On the basis of this comprehensive analysis, the authors have identified structural and genetic abnormalities associated with neurological and psychiatric disorders, as well as some nondisease traits, and have created a valuable resource providing some insights into the underlying neurobiology.

Here is the Zhao et al. abstract, followed by a graphic from Filley's review.

Brain regions communicate with each other through tracts of myelinated axons, commonly referred to as white matter. We identified common genetic variants influencing white matter microstructure using diffusion magnetic resonance imaging of 43,802 individuals. Genome-wide association analysis identified 109 associated loci, 30 of which were detected by tract-specific functional principal components analysis. A number of loci colocalized with brain diseases, such as glioma and stroke. Genetic correlations were observed between white matter microstructure and 57 complex traits and diseases. Common variants associated with white matter microstructure altered the function of regulatory elements in glial cells, particularly oligodendrocytes. This large-scale tract-specific study advances the understanding of the genetic architecture of white matter and its genetic links to a wide spectrum of clinical outcomes.

 

Out-group animosity drives engagement on social media

A disheartening analysis by Rathje et al.:  

Significance

Almost four billion people around the world now use social media platforms such as Facebook and Twitter, and social media is one of the primary ways people access news or receive communications from politicians. However, social media may be creating perverse incentives for divisive content because this content is particularly likely to go “viral.” We report evidence that posts about political opponents are substantially more likely to be shared on social media and that this out-group effect is much stronger than other established predictors of social media sharing, such as emotional language. These findings contribute to scholarly debates about the role of social media in political polarization and can inform solutions for creating healthier social media environments.

Abstract

There has been growing concern about the role social media plays in political polarization. We investigated whether out-group animosity was particularly successful at generating engagement on two of the largest social media platforms: Facebook and Twitter. Analyzing posts from news media accounts and US congressional members (n = 2,730,215), we found that posts about the political out-group were shared or retweeted about twice as often as posts about the in-group. Each individual term referring to the political out-group increased the odds of a social media post being shared by 67%. Out-group language consistently emerged as the strongest predictor of shares and retweets: the average effect size of out-group language was about 4.8 times as strong as that of negative affect language and about 6.7 times as strong as that of moral-emotional language—both established predictors of social media engagement. Language about the out-group was a very strong predictor of “angry” reactions (the most popular reactions across all datasets), and language about the in-group was a strong predictor of “love” reactions, reflecting in-group favoritism and out-group derogation. This out-group effect was not moderated by political orientation or social media platform, but stronger effects were found among political leaders than among news media accounts. In sum, out-group language is the strongest predictor of social media engagement across all relevant predictors measured, suggesting that social media may be creating perverse incentives for content expressing out-group animosity.

Seven nuggets on how we confuse ourselves about our brains and our world.

In a series of posts starting on Nov. 27, 2020 I attempted to abstract and condense the ideas in Lisa Feldman Barrett’s 2017 book “How Emotions Are Made: The Secret Life of the Brain”. That book is a hard slog, as was my series of posts on its contents. Barrett also did her own condensation in her followup book, “Seven and a Half Lessons About the Brain,” that appeared in late 2020 at the same time as my posts, and I’ve finally gotten around to scanning through it. I want to pass on her brief epilogue that extracts a few crisp nuggets from her lessons:

ONCE UPON A TIME, you were a little stomach on a stick, floating in the sea. Little by little, you evolved. You grew sensory systems and learned that you were part of a bigger world. You grew bodily systems to navigate that world efficiently. And you grew a brain that ran a budget for your body. You learned to live in groups with all the other little brains-in-bodies. You crawled out of the water and onto land. And across the expanse of evolutionary time - with the innovation that comes from trial and error and the deaths of trillions of animals - you ended up with a human brain. A brain that can do so many impressive things but at the same time severely misunderstands itself.

-A brain that constructs such rich mental experiences that we feel like emotion and reason wrestle inside us 

-A brain that’s so complex that we describe it by metaphors and mistake them for knowledge 

-A brain that’s so skilled at rewiring itself that we think we’re born with all sorts of things that we actually learn 

-A brain that’s so effective at hallucinating that we believe we see the world objectively, and so fast at predicting that we mistake our movements for reactions 

-A brain that regulates other brains so invisibly that we presume we’re independent of each other 

-A brain that creates so many kinds of minds that we assume there’s a single human nature to explain them all 

-A brain that’s so good at believing its own inventions that we mistake social reality for the natural world

We know much about the brain today, but there are still so many more lessons to learn. For now, at least, we’ve learned enough to sketch our brain’s fantastical evolutionary journey and consider the implications for some of the most central and challenging aspects of our lives.

Our kind of brain isn’t the biggest in the animal kingdom, and it’s not the best in any objective sense. But it’s ours. It’s the source of our strengths and our foibles. It gives us our capacity to build civilizations and our capacity to tear down each other. It makes us simply, imperfectly, gloriously human.

In our brains everything changes

Sometimes learning the hard neuroscience of how our brains work leaves me feeling a bit queasy. The first time this happened was when I learned about the Libet experiments that showed that cells in our motor cortex start a movement well before we ‘decide’ to initiate it. “We” think we are initiating a movement when in fact “it” (those brain cells) are already well on their way to doing it. So what happened to my ‘free will’? Well...there is a work around for that problem that I explain in my “I Illusion” and subsequent web lectures. 

 A further uncomfortable jolt comes on seeing evidence the brain cells that become active during a familiar experience can change over time. Each instance of the recall of an important event can recruit a different group of nerve cells, because each time the memory is fetched from the neuronal ‘library’ it gets put back, sometimes slightly altered, in different nerve cell collections and connections. A very striking example of this has been provided by Schoonover et al. Who show that the network of nerve cells active when a particular smell triggers a specific behavior changes over time, moving to different brain areas. This is an example of ‘representational plasticity’ which is discussed in a review article by Rule et al. 

This conflicts with our common sense view of how our minds should work. If you have an experience and then later remember it, you must have put it somewhere in your brain’s library of nerve cell connections, like a book on a library shelf, so that all you have to do to remember something is go fetch it. If the experience is an emotional one it couples with a hard wired circuit for that emotion. This essentialist view of how our minds work is being thoroughly displaced as experimental evidence continues to accumulate showing that in each moment we are constructing our experience anew - reminding of the Buddhist saying that the river you view flowing past is never the same twice. The series of MindBlog posts (starting here) on the work and ideas of Barrett covers this material. 

It is from constant change and flux in our evolved neuroendocrine circuitry that we generate the illusion of certainty or constancy - expectations of selves, rules, objects, and emotions that stay in place. We model the world we expect to see before each moment we are about to enter. If our expectations are not met, then our brains perk up to adjust them appropriately.  

 

Lack of mathematical education impacts brain development and future attainment

From Zacharopoulos et al.:  

 Significance

Our knowledge of the effect of a specific lack of education on the brain and cognitive development is currently poor but is highly relevant given differences between countries in their educational curricula and the differences in opportunities to access education. We show that within the same society, adolescent students who specifically lack mathematical education exhibited reduced brain inhibition levels in a key brain area involved in reasoning and cognitive learning. Importantly, these brain inhibition levels predicted mathematical attainment ∼19 mo later, suggesting they play a role in neuroplasticity. Our study provides biological understanding of the impact of the lack of mathematical education on the developing brain and the mutual play between biology and education.

Abstract

Formal education has a long-term impact on an individual’s life. However, our knowledge of the effect of a specific lack of education, such as in mathematics, is currently poor but is highly relevant given the extant differences between countries in their educational curricula and the differences in opportunities to access education. Here we examined whether neurotransmitter concentrations in the adolescent brain could classify whether a student is lacking mathematical education. Decreased γ-aminobutyric acid (GABA) concentration within the middle frontal gyrus (MFG) successfully classified whether an adolescent studies math and was negatively associated with frontoparietal connectivity. In a second experiment, we uncovered that our findings were not due to preexisting differences before a mathematical education ceased. Furthermore, we showed that MFG GABA not only classifies whether an adolescent is studying math or not, but it also predicts the changes in mathematical reasoning ∼19 mo later. The present results extend previous work in animals that has emphasized the role of GABA neurotransmission in synaptic and network plasticity and highlight the effect of a specific lack of education on MFG GABA concentration and learning-dependent plasticity. Our findings reveal the reciprocal effect between brain development and education and demonstrate the negative consequences of a specific lack of education during adolescence on brain plasticity and cognitive functions.

Decision-making ability, psychopathology, and brain connectivity

An open access review offered by Dolan and his colleagues continues the story of correlating our human competencies with our brain structures. They describe

...a new cognitive construct—decision acuity—that captures global decision-making ability. High decision acuity prominently reflected low decision variability. Decision acuity showed acceptable reliability, increased with age, and was associated with mental health symptoms independently of intelligence. Crucially, it was associated with distinctive resting-state networks, in particular in brain regions typically engaged by decision-making tasks. The association between decision acuity and functional connectivity was temporally stable and distinct from that of IQ.

Highlights

• Young people have a general decision-making ability, which we call “decision acuity” 

• Decision acuity is reflected in how strongly connected certain brain networks are 

• Low decision acuity is associated with general social function psychopathology

Summary

Decision-making is a cognitive process of central importance for the quality of our lives. Here, we ask whether a common factor underpins our diverse decision-making abilities. We obtained 32 decision-making measures from 830 young people and identified a common factor that we call “decision acuity,” which was distinct from IQ and reflected a generic decision-making ability. Decision acuity was decreased in those with aberrant thinking and low general social functioning. Crucially, decision acuity and IQ had dissociable brain signatures, in terms of their associated neural networks of resting-state functional connectivity. Decision acuity was reliably measured, and its relationship with functional connectivity was also stable when measured in the same individuals 18 months later. Thus, our behavioral and brain data identify a new cognitive construct that underpins decision-making ability across multiple domains. This construct may be important for understanding mental health, particularly regarding poor social function and aberrant thought patterns.

Giving help to others may increase your life span.

An interesting analysis from Chen et al.: 

Significance

Social support is a key contributor to mortality risk, with effects comparable in magnitude (though opposite in direction) to smoking and obesity. Research has largely focused on either support received or support given; yet, everyday social relationships typically involve interchanges of support rather than only giving or only receiving. Using a longitudinal US national sample, this article elucidates how the balance of social support (amount of giving one does on a monthly basis relative to receiving support) relates to all-cause mortality over a 23-y follow-up period. Although correlational, one possible implication of the findings is that encouraging individuals to give support (e.g., helping others with errands) in moderation, while also being willing to accept support, may have longevity benefits.

Abstract

While numerous studies exist on the benefits of social support (both receiving and giving), little research exists on how the balance between the support that individuals regularly give versus that which they receive from others relates to physical health. In a US national sample of 6,325 adults from the National Survey of Midlife Development in the United States, participants were assessed at baseline on hours of social support given and received on a monthly basis, with all-cause mortality data collected from the National Death Index over a 23-y follow-up period. Participants who were relatively balanced in the support they gave compared to what they received had a lower risk of all-cause mortality than those who either disproportionately received support from others (e.g., received more hours of support than they gave each month) or disproportionately gave support to others (e.g., gave many more hours of support a month than they received). These findings applied to instrumental social support (e.g., help with transportation, childcare). Additionally, participants who gave a moderate amount of instrumental social support had a lower risk of all-cause mortality than those who either gave very little support or those who gave a lot of support to others. Associations were evident over and above demographic, medical, mental health, and health behavior covariates. Although results are correlational, one interpretation is that promoting a balance, in terms of the support that individuals regularly give relative to what they receive in their social relationships, may not only help to strengthen the social fabric of society but may also have potential physical health benefits.

Our 'Self' extends vastly beyond our brain.

I want to pass on two interesting articles that review how the self we usually take to be largely inside our heads (somewhere behind the eyes) in fact has meaning only in contexts that extend vastly beyond the little grey cells in our cranium. Annie Murphy Paul notes four basic extensions that let our brains be less workhorse, and more orchestra conductor.

...the first and most obvious being our tools. Technology is designed to fulfill just this function — who remembers telephone numbers anymore, now that our smartphones can supply them?

Our external memory stores have evolved from marks on clay tablets through printed books to bytes stored in the cloud. 

A second resource is our bodies:

The burgeoning field of embodied cognition has demonstrated that the body — its sensations, gestures and movements — plays an integral role in the thought processes that we usually locate above the neck. The body is especially adept at alerting us to patterns of events and experience, patterns that are too complex to be held in the conscious mind. When a scenario we encountered before crops up again, the body gives us a nudge: communicating with a shiver or a sigh, a quickening of the breath or a tensing of the muscles. Those who are attuned to such cues can use them to make more-informed decisions. A study led by a team of economists and neuroscientists in Britain, for instance, reported that financial traders who were better at detecting their heartbeats — a standard test of what is known as interoception, or the ability to perceive internal signals — made more profitable investments and lasted longer in that notoriously volatile profession.

This second extension is the subject of the other article I want to mention, in which Emily Underwood does a review of communication between the brain and other organs, mediated by the vagus nerve, that shapes how we think, remember, and feel (not open source, but motivated readers can obtain a copy by emailing me).

Scientists are unraveling how our organs talk to the brain and how the brain talks back. That two-way communication, known as interoception, encompasses a complex system of nerves and hormones, including the vagus nerve, a massive network of fibers that travel from nearly every internal organ to the base of the brain and back again. Scientist have long known the vagus nerve carries signals between the organs and the brainstem. But new studies show signals carried by the vagus climb beyond the brainstem and into brain regions involved in memory, emotion, and decision-making. The research is challenging traditional distinctions between disorders of the brain and body, and may even hold clues to the nature of consciousness.

Now, back to Paul's article, and her third extension of our brain:

Another extraneural resource available for our use is physical space. Moving mental contents out of our heads and onto the space of a sketch pad or whiteboard allows us to inspect it with our senses, a cognitive bonus that the psychologist Daniel Reisberg calls “the detachment gain.”...Three-dimensional space offers additional opportunities for offloading mental work and enhancing the brain’s powers. When we turn a problem to be solved into a physical object that we can interact with, we activate the robust spatial abilities that allow us to navigate through real-world landscapes. This suite of human strengths, honed over eons of evolution, is wasted when we sit still and think.

A fourth extension of our minds...

...can be found in other people’s minds. We are fundamentally social creatures, oriented toward thinking with others. Problems arise when we do our thinking alone — for example, the well-documented phenomenon of confirmation bias, which leads us to preferentially attend to information that supports the beliefs we already hold. According to the argumentative theory of reasoning, advanced by the cognitive scientists Hugo Mercier and Dan Sperber, this bias is accentuated when we reason in solitude. Humans’ evolved faculty for reasoning is not aimed at arriving at objective truth, Mercier and Sperber point out; it is aimed at defending our arguments and scrutinizing others’. It makes sense, they write, “for a cognitive mechanism aimed at justifying oneself and convincing others to be biased and lazy. The failures of the solitary reasoner follow from the use of reason in an ‘abnormal’ context’” — that is, a nonsocial one.

All four of these extraneural resources — technology, the body, physical space, social interaction — can be understood as mental extensions that allow the brain to accomplish far more than it could on its own. This is the theory of the extended mind, introduced more than two decades ago by the philosophers Andy Clark and David Chalmers. A 1998 article of theirs published in the journal Analysis began by posing a question that would seem to have an obvious answer: “Where does the mind stop and the rest of the world begin?” They went on to offer an unconventional response. The mind does not stop at the usual “boundaries of skin and skull,” they maintained. Rather, the mind extends into the world and augments the capacities of the biological brain with outside-the-brain resources.

Compared to the attention we lavish on the brain, we expend relatively little effort on cultivating our ability to think outside the brain...The limits of this approach have become painfully evident. The days when we could do it all in our heads are over. Our knowledge is too abundant, our expertise too specialized, our challenges too enormous. The best chance we have to thrive in the extraordinarily complex world we’ve created is to allow that world to assume some of our mental labor. Our brains can’t do it alone.

A.I. should be afraid of us.

Alan Burdick does a nice summary of some recent work on interactions between humans and artificial intelligence algorithms designed to appear empathetic:

Numerous studies have found that when people are placed in a situation where they can cooperate with a benevolent A.I., they are less likely to do so than if the bot were an actual person...We basically treat a perfect stranger better than A.I.

A study by Deroy and colleagues found

...that people were less likely to cooperate with a bot even when the bot was keen to cooperate. It’s not that we don’t trust the bot, it’s that we do: The bot is guaranteed benevolent, a capital-S sucker, so we exploit it.

That conclusion was borne out by reports afterward from the study’s participants. “Not only did they tend to not reciprocate the cooperative intentions of the artificial agents,” Dr. Deroy said, “but when they basically betrayed the trust of the bot, they didn’t report guilt, whereas with humans they did.” She added, “You can just ignore the bot and there is no feeling that you have broken any mutual obligation.”

This could have real-world implications. When we think about A.I., we tend to think about the Alexas and Siris of our future world, with whom we might form some sort of faux-intimate relationship. But most of our interactions will be one-time, often wordless encounters. Imagine driving on the highway, and a car wants to merge in front of you. If you notice that the car is driverless, you’ll be far less likely to let it in. And if the A.I. doesn’t account for your bad behavior, an accident could ensue.

“What sustains cooperation in society at any scale is the establishment of certain norms,” Dr. Deroy said. “The social function of guilt is exactly to make people follow social norms that lead them to make compromises, to cooperate with others. And we have not evolved to have social or moral norms for non-sentient creatures and bots...what guarantees that the behavior that gets repeated, and where you show less politeness, less moral obligation, less cooperativeness, will not color and contaminate the rest of your behavior when you interact with another human?"

There are similar consequences for A.I., too. “If people treat them badly, they’re programed to learn from what they experience,” she said. “An A.I. that was put on the road and programmed to be benevolent should start to be not that kind to humans, because otherwise it will be stuck in traffic forever...

There we have it: The true Turing test is road rage. When a self-driving car starts honking wildly from behind because you cut it off, you’ll know that humanity has reached the pinnacle of achievement. By then, hopefully, A.I therapy will be sophisticated enough to help driverless cars solve their anger-management issues.

Your blood proteins can tell you the best kind of exercise for your body

Since I am heading into my 80th year, and realizing that any further years must be regarded as a gift from nature, I'm attentive to anything that NYTimes "Phys Ed" columnist Gretchen Reynolds (who is no spring chicken) writes about exercise and aerobic fittness (both of which are strongly linked to longevity.) Most recently, she describes work by Robbins et al. that finds a correlation between the levels of different blood proteins and how individual respond to exercise.

If we all begin the same exercise routine tomorrow, some of us will become much fitter, others will get a little more in shape, and a few of us may actually lose fitness. Individual responses to exercise can vary that wildly and, until now, unpredictably. But a fascinating new study of more than 650 men and women suggests that the levels of certain proteins in our bloodstreams might foretell whether and how we will respond to various exercise regimens.

Using state-of-the-art molecular tools, the scientists began enumerating the numbers and types of thousands of proteins in each of the 654 people’s bloodstreams. Then they tabulated those figures with data about everyone’s aerobic fitness before and after their five months of exercise...The levels of 147 proteins were strongly associated with people’s baseline fitness, the researchers found. If some of those protein numbers were high and others low, the resulting molecular profiles indicated how fit someone was.

More intriguing, a separate set of 102 proteins tended to predict people’s physical responses to exercise. Higher and lower levels of these molecules — few of which overlapped with the proteins related to people’s baseline fitness — prophesied the extent to which someone’s aerobic capacity would increase, if at all, with exercise...Finally, because aerobic fitness is so strongly linked to longevity, the scientists crosschecked levels of the various fitness-related proteins in the blood of people enrolled in a separate health study that included mortality records, and found that protein signatures implying lower or greater fitness response likewise signified shorter or longer lives.

Taken as a whole, the new study’s results suggest that “molecular profiling tools might help to tailor” exercise plans. Someone whose bloodstream protein signature suggests he or she might gain little fitness from a standard, moderate walking, cycling or swimming routine, for instance, might be nudged toward higher-intensity workouts or resistance training.

Equality and Equity in the Life Sciences

After yesterday's heavy post describing 'Four Americas.' - with the last listed being 'Justice America' - rising out of the age of the Millenials and addressing the systemic racism that has permeated American life and politics since the 1700's - I decided to take a brief rest by going back to my reviewing of the tables of contents of various life science journals, a respite, I thought, of looking at politically neutral basic science. No such luck...nothing is politically neutral in these times...virtually all of the journals I look at are attempting to examine and atone for their past inattention to issues of equality and equity. From the tables of contents of the first four journals in my queue of Journals to have a look at:

From Cell: Affirming NIH’s commitment to addressing structural racism in the biomedical research enterprise

NIH has acknowledged and committed to ending structural racism. The framework for NIH’s approach, summarized here, includes understanding barriers; developing robust health disparities/equity research; improving its internal culture; being transparent and accountable; and changing the extramural ecosystem so that diversity, equity, and inclusion are reflected in funded research and the biomedical workforce.

From Current Biology: Trends Voices: On inclusion and diversity

Meet with us to share personal stories of your experience as a scientist, as well as accounts of what you’re doing to redress existing bias in scientific inquiry, for the benefit of science and society. Book a meeting.

From Proceedings of the National Academy of Sciences:

News Feature: Keeping Black students in STEM

From Social Cognitive and Affective Neuroscience:

The neural underpinnings of making racial distinctions.