Brain regions involved in compensating for lost body parts.

From Striem-Amit et al.:

Significance

What determines the role of brain regions and their plasticity when typical inputs or experience is not provided? To what extent can extreme compensatory use affect brain organization? We tested the reorganization of primary and association sensorimotor cortex hand-selective areas in people born without hands, who use their feet for everyday tasks. We found that their primary sensorimotor hand area is preferentially activated for nearby body parts that cannot serve as effectors. In contrast, foot-selective compensatory plasticity was found in the association cortex, in an area typically involved in manual tool use. This shows limitations of compensatory plasticity and experience in modifying brain organization of early topographical cortex, as compared with association cortices where function-based organization is the driving factor.

Abstract

What forces direct brain organization and its plasticity? When brain regions are deprived of their input, which regions reorganize based on compensation for the disability and experience, and which regions show topographically constrained plasticity? People born without hands activate their primary sensorimotor hand region while moving body parts used to compensate for this disability (e.g., their feet). This was taken to suggest a neural organization based on functions, such as performing manual-like dexterous actions, rather than on body parts, in primary sensorimotor cortex. We tested the selectivity for the compensatory body parts in the primary and association sensorimotor cortex of people born without hands (dysplasic individuals). Despite clear compensatory foot use, the primary sensorimotor hand area in the dysplasic subjects showed preference for adjacent body parts that are not compensatorily used as effectors. This suggests that function-based organization, proposed for congenital blindness and deafness, does not apply to the primary sensorimotor cortex deprivation in dysplasia. These findings stress the roles of neuroanatomical constraints like topographical proximity and connectivity in determining the functional development of primary cortex even in extreme, congenital deprivation. In contrast, increased and selective foot movement preference was found in dysplasics’ association cortex in the inferior parietal lobule. This suggests that the typical motor selectivity of this region for manual actions may correspond to high-level action representations that are effector-invariant. These findings reveal limitations to compensatory plasticity and experience in modifying brain organization of early topographical cortex compared with association cortices driven by function-based organization.

Residential isolation of disadvantaged groups is not mitigated by extensive urban mobility.

Wang et al. offer yet another approach to observing the intractability of racial segregation in large cities:

Significance

Living in disadvantaged neighborhoods is widely assumed to undermine life chances because residents are isolated from neighborhoods with greater resources. Yet, residential isolation may be mitigated by individuals spending much of their everyday lives outside their home neighborhoods, a possibility that has been difficult to assess on a large scale. Using new methods to analyze urban mobility in the 50 largest American cities, we find that residents of primarily black and Hispanic neighborhoods—whether poor or not—are far less exposed to either nonpoor or white middle-class neighborhoods than residents of primarily white neighborhoods. Although residents of disadvantaged neighborhoods regularly travel as far and to as many different neighborhoods as those from advantaged neighborhoods, their relative isolation and segregation persist.

Abstract

Influential research on the negative effects of living in a disadvantaged neighborhood assumes that its residents are socially isolated from nonpoor or “mainstream” neighborhoods, but the extent and nature of such isolation remain in question. We develop a test of neighborhood isolation that improves on static measures derived from commonly used census reports by leveraging fine-grained dynamic data on the everyday movement of residents in America’s 50 largest cities. We analyze 650 million geocoded Twitter messages to estimate the home locations and travel patterns of almost 400,000 residents over 18 mo. We find surprisingly high consistency across neighborhoods of different race and income characteristics in the average travel distance (radius) and number of neighborhoods traveled to (spread) in the metropolitan region; however, we uncover notable differences in the composition of the neighborhoods visited. Residents of primarily black and Hispanic neighborhoods—whether poor or not—are far less exposed to either nonpoor or white middle-class neighborhoods than residents of primarily white neighborhoods. These large racial differences are notable given recent declines in segregation and the increasing diversity of American cities. We also find that white poor neighborhoods are substantially isolated from nonpoor white neighborhoods. The results suggest that even though residents of disadvantaged neighborhoods travel far and wide, their relative isolation and segregation persist.

Chimps can psych out humans

Interesting work from Eckert et al. shows that chimps can use mental state information revealed by experimenters' biases in selecting food items.

Great apes have been shown to be intuitive statisticians: they can use proportional information within a population to make intuitive probability judgments about randomly drawn samples [unpublished data]. Humans, from early infancy onward, functionally integrate intuitive statistics with other cognitive domains to judge the randomness of an event. To date, nothing is known about such cross-domain integration in any nonhuman animal, leaving uncertainty about the origins of human statistical abilities. We investigated whether chimpanzees take into account information about psychological states of experimenters (their biases and visual access) when drawing statistical inferences. We tested 21 sanctuary-living chimpanzees in a previously established paradigm that required subjects to infer which of two mixed populations of preferred and non-preferred food items was more likely to lead to a desired outcome for the subject. In a series of three experiments, we found that chimpanzees chose based on proportional information alone when they had no information about experimenters’ preferences and (to a lesser extent) when experimenters had biases for certain food types but drew blindly. By contrast, when biased experimenters had visual access, subjects ignored statistical information and instead chose based on experimenters’ biases. Lastly, chimpanzees intuitively used a violation of statistical likelihoods as indication for biased sampling. Our results suggest that chimpanzees have a random sampling assumption that can be overridden under the appropriate circumstances and that they are able to use mental state information to judge whether this is necessary. This provides further evidence for a shared statistical inference mechanism in apes and humans.

Enhanced brain activity associated with highly superior memory.

Santangelo et al. show that people with superior memory have enhanced connectivity of their prefrontal cortex with their hippocampus and temporoparietal junction:

Significance

Recent research has identified human subjects who have highly superior autobiographical memory (HSAM). Here, we investigated, using fMRI, the neural activation induced by retrieval of autobiographical memories (AMs) and semantic memories (SMs) in subjects with HSAM and control subjects. While their brains were being scanned, subjects had to retrieve AMs as well as SMs (e.g., examples of animals). The subjects with HSAM displayed a superior ability to retrieve details of AMs, supported by enhanced activation of several brain regions, including the medial prefrontal cortex and temporoparietal junction, as well as increased connectivity of the prefrontal cortex with the hippocampus, a region well known to be involved in memory representation. These findings suggest that activation of these systems may play a critical role in enabling HSAM.

Abstract

Brain systems underlying human memory function have been classically investigated studying patients with selective memory impairments. The discovery of rare individuals who have highly superior autobiographical memory (HSAM) provides, instead, an opportunity to investigate the brain systems underlying enhanced memory. Here, we carried out an fMRI investigation of a group of subjects identified as having HSAM. During fMRI scanning, eight subjects with HSAM and 21 control subjects were asked to retrieve autobiographical memories (AMs) as well as non-AMs (e.g., examples of animals). Subjects were instructed to signal the “access” to an AM by a key press and to continue “reliving” it immediately after. Compared with controls, individuals with HSAM provided a richer AM recollection and were faster in accessing AMs. The access to AMs was associated with enhanced prefrontal/hippocampal functional connectivity. AM access also induced increased activity in the left temporoparietal junction and enhanced functional coupling with sensory cortices in subjects with HSAM compared with controls. In contrast, subjects with HSAM did not differ from controls in functional activity during the reliving phase. These findings, based on fMRI assessment, provide evidence of interaction of brain systems engaged in memory retrieval and suggest that enhanced activity of these systems is selectively involved in enabling more efficient access to past experiences in HSAM.

Are things getting better or worse?

In a recent New Yorker article Joshua Rothman discusses debate over assessing the state of the world, with major emphasis on Pinker book "Enlightenment Now", which was the subject of a series of MindBlog posts March 1 - March 12 of this year. Things like "Progressophobia" on the part of intellectuals, people seeing the past through rose colored glasses, and media emphasizing momentary crises over long term trends lead most people to think that the world is getting worse rather than better, which, Pinker says, is "wrong wrong, flat-earth wrong."

Rothman's brief reviews of a number of other books debating progress and optimism versus pessimism about the future make his article well worth reading. I'll pass on the end of the article (note especially the last paragraph), which points to a book by Hans Rosling:

In “Factfulness: Ten Reasons We’re Wrong About the World—and Why Things Are Better Than You Think,” the Swedish global-health statistician Hans Rosling, who wrote the book with his son and daughter-in-law, tries to find such a picture. Most depictions of the world, Rosling thinks, are either too optimistic or too pessimistic; if they don’t succumb to despair, they seem to look too quickly away from suffering. Rosling adopts a mantra—“Bad and better”—to avoid these extremes. “Think of the world as a premature baby in an incubator,” he suggests:

The baby’s health status is extremely bad, and her breathing, heart rate, and other important signs are tracked constantly so that changes for better or worse can quickly be seen. After a week, she is getting a lot better. On all the main measures, she is improving, but she still has to stay in the incubator because her health is still critical. Does it make sense to say that the infant’s situation is improving? Yes. Absolutely. Does it make sense to say it is bad? Yes, absolutely. Does saying “things are improving” imply that everything is fine, and we should all relax and not worry? No, not at all. Is it helpful to have to choose between bad and improving? Definitely not. It’s both. It’s both bad and better. Better, and bad, at the same time. . . . That is how we must think about the current state of the world.

Rosling’s image captures many of the perplexities of our collective situation. We desperately want the baby to survive. We also know that survival doesn’t guarantee happiness. The baby is struggling, and suffering, and will continue to do so; as a result, we’re more likely to be happy for her than she is to be happy for herself. (Pinker, similarly, is happier for us than we are.) It’s possible, moreover, that she’ll be saved only temporarily. No one is ever truly out of the woods.

In the meantime, the baby’s survival depends on the act of diagnosis. Until her ailments are identified, they can’t be cured. Problems and progress are inextricable, and the history of improvement is also the history of problem-discovery. Diagnosis, of course, is an art in itself; it’s possible to misunderstand problems, or to overstate them, and, in doing so, to make them worse. But a world in which no one complained—in which we only celebrated how good we have it—would be a world that never improved. The spirit of progress is also the spirit of discontent.

Piano training enhances speech perception.

Fascinating work from an international collaboration of Desimone at M.I.T., Nan at Beijing Normal Univ., and others:

Significance

Musical training is beneficial to speech processing, but this transfer’s underlying brain mechanisms are unclear. Using pseudorandomized group assignments with 74 4- to 5-year-old Mandarin-speaking children, we showed that, relative to an active control group which underwent reading training and a no-contact control group, piano training uniquely enhanced cortical responses to pitch changes in music and speech (as lexical tones). These neural enhancements further generalized to early literacy skills: Compared with the controls, the piano-training group also improved behaviorally in auditory word discrimination, which was correlated with their enhanced neural sensitivities to musical pitch changes. Piano training thus improves children’s common sound processing, facilitating certain aspects of language development as much as, if not more than, reading instruction.

Abstract

Musical training confers advantages in speech-sound processing, which could play an important role in early childhood education. To understand the mechanisms of this effect, we used event-related potential and behavioral measures in a longitudinal design. Seventy-four Mandarin-speaking children aged 4–5 y old were pseudorandomly assigned to piano training, reading training, or a no-contact control group. Six months of piano training improved behavioral auditory word discrimination in general as well as word discrimination based on vowels compared with the controls. The reading group yielded similar trends. However, the piano group demonstrated unique advantages over the reading and control groups in consonant-based word discrimination and in enhanced positive mismatch responses (pMMRs) to lexical tone and musical pitch changes. The improved word discrimination based on consonants correlated with the enhancements in musical pitch pMMRs among the children in the piano group. In contrast, all three groups improved equally on general cognitive measures, including tests of IQ, working memory, and attention. The results suggest strengthened common sound processing across domains as an important mechanism underlying the benefits of musical training on language processing. In addition, although we failed to find far-transfer effects of musical training to general cognition, the near-transfer effects to speech perception establish the potential for musical training to help children improve their language skills. Piano training was not inferior to reading training on direct tests of language function, and it even seemed superior to reading training in enhancing consonant discrimination.

Mechanism of white matter changes induced by meditation?

Posner and collaborators, who previously have shown changes in brain white matter induced by meditation, suggest a possible mechanism, using a mouse model.

Meditation has been shown to modify brain connections. However, the cellular mechanisms by which this occurs are not known. We hypothesized that changes in white matter found following meditation may be due to increased rhythmicity observed in frontal areas in the cortex. The current study in mice tested this directly by rhythmically stimulating cells in the frontal midline. We found that such stimulation caused an increase in connectivity due to changes in the axons in the corpus callosum, which transmit impulses to and from the frontal midline. This work provides a plausible but not proven mechanism through which a mental activity such as meditation can improve brain connectivity.

The neuroscience of mindfulness meditation

I completely missed this review article by Posner and colleagues when it appeared, and am grateful for Bäumli's mention of it in her recent brief essay, which gives this link for downloading it. It has a mind numbing amount of information on research into the brain correlates of meditative practice and competence, summary tables, references, graphics. In this post I'm passing passing on the summary of key points and one graphic:

Key points

It is proposed that the mechanism through which mindfulness meditation exerts its effects is a process of enhanced self-regulation, including attention control, emotion regulation and self-awareness.

Research on mindfulness meditation faces a number of important challenges in study design that limit the interpretation of existing studies.

A number of changes in brain structure have been related to mindfulness meditation.

Mindfulness practice enhances attention. The anterior cingulate cortex is the region associated with attention in which changes in activity and/or structure in response to mindfulness meditation are most consistently reported.

Mindfulness practice improves emotion regulation and reduces stress. Fronto-limbic networks involved in these processes show various patterns of engagement by mindfulness meditation.

Meditation practice has the potential to affect self-referential processing and improve present-moment awareness. The default mode networks — including the midline prefrontal cortex and posterior cingulate cortex, which support self-awareness — could be altered following mindfulness training.

Mindfulness meditation has potential for the treatment of clinical disorders and might facilitate the cultivation of a healthy mind and increased well-being.

Future research into mindfulness meditation should use randomized and actively controlled longitudinal studies with large sample sizes to validate previous findings.

The effects of mindfulness practice on neural structure and function need to be linked to behavioural performance, such as cognitive, affective and social functioning, in future research.

The complex mental state of mindfulness is likely to be supported by the large-scale brain networks; future work should take this into account rather than being restricted to activations in single brain areas.

Legend - Schematic view of some of the brain regions involved in attention control (the anterior cingulate cortex and the striatum), emotion regulation (multiple prefrontal regions, limbic regions and the striatum) and self-awareness (the insula, medial prefrontal cortex and posterior cingulate cortex and precuneus).

When persistence doesn't pay - the sunk cost bias.

Sweis et al. show that sensitivity to time invested in pursuit of a reward occurs similarly in mice, rats, and humans. All three display a resistance to giving up their pursuit of a reward in a foraging context, but only after they have made the decision to pursue the reward. They suggest that there are two independent valuation processes, one assessing whether to accept an offer and the other — the one that is susceptible to sunk costs — assessing whether to continue investing in the choice. Their abstract:

Sunk costs are irrecoverable investments that should not influence decisions, because decisions should be made on the basis of expected future consequences. Both human and nonhuman animals can show sensitivity to sunk costs, but reports from across species are inconsistent. In a temporal context, a sensitivity to sunk costs arises when an individual resists ending an activity, even if it seems unproductive, because of the time already invested. In two parallel foraging tasks that we designed, we found that mice, rats, and humans show similar sensitivities to sunk costs in their decision-making. Unexpectedly, sensitivity to time invested accrued only after an initial decision had been made. These findings suggest that sensitivity to temporal sunk costs lies in a vulnerability distinct from deliberation processes and that this distinction is present across species.

Declining mental health among disadvantaged Americans.

Cherlin summarizes work by Goldman et al. that demonstrates "a troubling portrait of declining psychological health among non-Hispanic whites in mid- and later-life between the mid-1990s and the early 2010s... Equally troubling is the concentration of these declines among individuals with lower SES (socioeconomic status...life satisfaction declined for people at the 10th, 25th, and 50th percentiles of SES, remained constant for people at the 75th percentile, and increased for people at the 90th percentile. To the list of widening inequalities in the United States, which center on economic inequality, we must now add inequality in psychological health.

The Goldman et al. Abstract:

Significance

In the past few years, references to the opioid epidemic, drug poisonings, and associated feelings of despair among Americans, primarily working-class whites, have flooded the media, and related patterns of mortality have been of increasing interest to social scientists. Yet, despite recurring references to distress or despair in journalistic accounts and academic studies, there has been little analysis of whether psychological health among American adults has worsened over the past two decades. Here, we use data from national samples of adults in the mid-1990s and early 2010s to demonstrate increasing distress and declining well-being that was concentrated among low-socioeconomic-status individuals but spanned the age range from young to older adults.

Abstract

Although there is little dispute about the impact of the US opioid epidemic on recent mortality, there is less consensus about whether trends reflect increasing despair among American adults. The issue is complicated by the absence of established scales or definitions of despair as well as a paucity of studies examining changes in psychological health, especially well-being, since the 1990s. We contribute evidence using two cross-sectional waves of the Midlife in the United States (MIDUS) study to assess changes in measures of psychological distress and well-being. These measures capture negative emotions such as sadness, hopelessness, and worthlessness, and positive emotions such as happiness, fulfillment, and life satisfaction. Most of the measures reveal increasing distress and decreasing well-being across the age span for those of low relative socioeconomic position, in contrast to little decline or modest improvement for persons of high relative position.

Therapy for NYTAD - read about citrus micro-jets!

What is NYTAD? My just made up acronym for “New York Times Anxiety Disorder” - what I have to resist during my daily glance through the endless list of NYT and WaPo articles on the awful human being who serves as our president. And then, unexpectedly, a point of light. A neat article about something else: the microjets of citrus oil you see when you squeeze the skin of an orange or lemon. It turns out that the layered construction of the citrus exocarp allows for the buildup of fluid pressure in citrus oil gland reservoirs and their subsequent explosive rupture . I'll pass on the abstract of the PNAS article to which it refers, which gives the interesting details, along with a video.

Significance

Here we show a unique, natural method for microscale jetting of fluid made possible by the tuning of material properties from which the jets emanate. The composite, layered construction of the citrus exocarp allows for the buildup of fluid pressure in citrus oil gland reservoirs and their subsequent explosive rupture. Citrus jetting has not been documented in literature, and its purpose is unknown. This method for microscale fluid dispersal requires no auxiliary equipment and may open avenues for new methods of medicine and chemical delivery. We show how jet kinematics are related to substrate properties and reservoir shape.

Abstract

The rupture of oil gland reservoirs housed near the outer surface of the citrus exocarp is a common experience to the discerning citrus consumer and bartenders the world over. These reservoirs often rupture outwardly in response to bending the peel, which compresses the soft material surrounding the reservoirs, the albedo, increasing fluid pressure in the reservoir. Ultimately, fluid pressure exceeds the failure strength of the outermost membrane, the flavedo. The ensuing high-velocity discharge of oil and exhaustive emptying of oil gland reservoirs creates a method for jetting small quantities of the aromatic oil. We compare this jetting behavior across five citrus hybrids through high-speed videography. The jetting oil undergoes an extreme acceleration to reach velocities in excess of 10 m/s. Through material characterization and finite element simulations, we rationalize the combination of tuned material properties and geometries enabling the internal reservoir pressures that produce explosive dispersal, finding the composite structure of the citrus peel is critical for microjet production.

Crows make mental templates.

Weintraub points to further studies from the University of Aukland School of Psychology on the extraordinary New Caledonian crows that have been shown to learn tool use. They also appear to use “mental template matching” - forming an image in their heads of tools they have seen used by others, and then copying them.

 

Perceptual and judgement creep.

Fascinating work by Gilbert and colleagues:

Why do some social problems seem so intractable? In a series of experiments, we show that people often respond to decreases in the prevalence of a stimulus by expanding their concept of it. When blue dots became rare, participants began to see purple dots as blue; when threatening faces became rare, participants began to see neutral faces as threatening; and when unethical requests became rare, participants began to see innocuous requests as unethical. This “prevalence-induced concept change” occurred even when participants were forewarned about it and even when they were instructed and paid to resist it. Social problems may seem intractable in part because reductions in their prevalence lead people to see more of them.

Authentic lies.

Hahl et al. suggest how a blatantly lying demagogue (guess who?) can be perceived as authentic:

We develop and test a theory to address a puzzling pattern that has been discussed widely since the 2016 U.S. presidential election and reproduced here in a post-election survey: how can a constituency of voters find a candidate “authentically appealing” (i.e., view him positively as authentic) even though he is a “lying demagogue” (someone who deliberately tells lies and appeals to non-normative private prejudices)? Key to the theory are two points: (1) “common-knowledge” lies may be understood as flagrant violations of the norm of truth-telling; and (2) when a political system is suffering from a “crisis of legitimacy” with respect to at least one political constituency, members of that constituency will be motivated to see a flagrant violator of established norms as an authentic champion of its interests. Two online vignette experiments on a simulated college election support our theory. These results demonstrate that mere partisanship is insufficient to explain sharp differences in how lying demagoguery is perceived, and that several oft-discussed factors—information access, culture, language, and gender—are not necessary for explaining such differences. Rather, for the lying demagogue to have authentic appeal, it is sufficient that one side of a social divide regards the political system as flawed or illegitimate.

Social media and the emergence of violence during protests.

The social media, and especially Twitter, are now integral to modern political behavior, with events online both reflecting and influencing actions offline. Mooijman et al. have used geolocated Twitter data to argue that moralization of protests leads to violent protests and increased support for violence.

In recent years, protesters in the United States have clashed violently with police and counter-protesters on numerous occasions. Despite widespread media attention, little scientific research has been devoted to understanding this rise in the number of violent protests. We propose that this phenomenon can be understood as a function of an individual’s moralization of a cause and the degree to which they believe others in their social network moralize that cause. Using data from the 2015 Baltimore protests, we show that not only did the degree of moral rhetoric used on social media increase on days with violent protests but also that the hourly frequency of morally relevant tweets predicted the future counts of arrest during protests, suggesting an association between moralization and protest violence. To better understand the structure of this association, we ran a series of controlled behavioural experiments demonstrating that people are more likely to endorse a violent protest for a given issue when they moralize the issue; however, this effect is moderated by the degree to which people believe others share their values. We discuss how online social networks may contribute to inflations of protest violence.

What is consciousness, and could machines have it?

I want to point to a lucid article by Dehaene, Lau, and Koulder that gives the most clear review I have seen of our current state of knowledge on the nature of human consciousness, which we need to define if we wish to consider the question of machines being conscious like us.   Here is the abstract, followed by a few edited clips that attempt to communicate the core points (motivated readers can obtain the whole text by emailing me):

The controversial question of whether machines may ever be conscious must be based on a careful consideration of how consciousness arises in the only physical system that undoubtedly possesses it: the human brain. We suggest that the word “consciousness” conflates two different types of information-processing computations in the brain: the selection of information for global broadcasting, thus making it flexibly available for computation and report (C1, consciousness in the first sense), and the self-monitoring of those computations, leading to a subjective sense of certainty or error (C2, consciousness in the second sense). We argue that despite their recent successes, current machines are still mostly implementing computations that reflect unconscious processing (C0) in the human brain. We review the psychological and neural science of unconscious (C0) and conscious computations (C1 and C2) and outline how they may inspire novel machine architectures.

C1: Global availability

This corresponds to the transitive meaning of consciousness (as in “The driver is conscious of the light”)... We can recall it, act upon it, and speak about it. This sense is synonymous with “having the information in mind”; among the vast repertoire of thoughts that can become conscious at a given time, only that which is globally available constitutes the content of C1 consciousness.

C2: Self-monitoring

Another meaning of consciousness is reflexive. It refers to a self-referential relationship in which the cognitive system is able to monitor its own processing and obtain information about itself..This sense of consciousness corresponds to what is commonly called introspection, or what psychologists call “meta-cognition”—the ability to conceive and make use of internal representations of one’s own knowledge and abilities.

CO: Unconscious processing: Where most of our intelligence lies

...many computations involve neither C1 nor C2 and therefore are properly called “unconscious” ...Cognitive neuroscience confirms that complex computations such as face or speech recognition, chess-game evaluation, sentence parsing, and meaning extraction occur unconsciously in the human brain—under conditions that yield neither global reportability nor self-monitoring. The brain appears to operate, in part, as a juxtaposition of specialized processors or “modules” that operate nonconsciously and, we argue, correspond tightly to the operation of current feedforward deep-learning networks.

The phenomenon of priming illustrates the remarkable depth of unconscious processing...Subliminal digits, words, faces, or objects can be invariantly recognized and influence motor, semantic, and decision levels of processing. Neuroimaging methods reveal that the vast majority of brain areas can be activated nonconsciously...Subliminal priming generalizes across visual-auditory modalities...Even the semantic meaning of sensory input can be processed without awareness by the human brain.

...subliminal primes can influence prefrontal mechanisms of cognitive control involved in the selection of a task...Neural mechanisms of decision-making involve accumulating sensory evidence that affects the probability of the various choices until a threshold is attained. This accumulation of probabilistic knowledge continues to happen even with subliminal stimuli. Bayesian inference and evidence accumulation, which are cornerstone computations for AI, are basic unconscious mechanisms for humans.

Reinforcement learning algorithms, which capture how humans and animals shape their future actions on the basis of history of past rewards, have excelled in attaining supra-human AI performance in several applications, such as playing Go. Remarkably, in humans, such learning appears to proceed even when the cues, reward, or motivation signals are presented below the consciousness threshold.

What additional computations are required for conscious processing?

C1: Global availability of relevant information

The need for integration and coordination. Integrating all of the available evidence to converge toward a single decision is a computational requirement that, we contend, must be faced by any animal or autonomous AI system and corresponds to our first functional definition of consciousness: global availability (C1)...Such decision-making requires a sophisticated architecture for (i) efficiently pooling over all available sources of information, including multisensory and memory cues; (ii) considering the available options and selecting the best one on the basis of this large information pool; (iii) sticking to this choice over time; and (iv) coordinating all internal and external processes toward the achievement of that goal.

Consciousness as access to an internal global workspace. We hypothesize that...On top of a deep hierarchy of specialized modules, a “global neuronal workspace,” with limited capacity, evolved to select a piece of information, hold it over time, and share it across modules. We call “conscious” whichever representation, at a given time, wins the competition for access to this mental arena and gets selected for global sharing and decision-making.

Relation between consciousness and attention. William James described attention as “the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought”. This definition is close to what we mean by C1: the selection of a single piece of information for entry into the global workspace. There is, however, a clear-cut distinction between this final step, which corresponds to conscious access, and the previous stages of attentional selection, which can operate unconsciously...What we call attention is a hierarchical system of sieves that operate unconsciously. Such unconscious systems compute with probability distributions, but only a single sample, drawn from this probabilistic distribution, becomes conscious at a given time. We may become aware of several alternative interpretations, but only by sampling their unconscious distributions over time.

Evidence for all-or-none selection in a capacity-limited system. The primate brain comprises a conscious bottleneck and can only consciously access a single item at a time. For instance, rivaling pictures or ambiguous words are perceived in an all-or-none manner; at any given time, we subjectively perceive only a single interpretation out of many possible ones [even though the others continue to be processed unconsciously]...Brain imaging in humans and neuronal recordings in monkeys indicate that the conscious bottleneck is implemented by a network of neurons that is distributed through the cortex, but with a stronger emphasis on high-level associative areas. ... Single-cell recordings indicate that each specific conscious percept, such as a person’s face, is encoded by the all-or-none firing of a subset of neurons in high-level temporal and prefrontal cortices, whereas others remain silent...the stable, reproducible representation of high-quality information by a distributed activity pattern in higher cortical areas is a feature of conscious processing. Such transient “meta-stability” seems to be necessary for the nervous system to integrate information from a variety of modules and then broadcast it back to them, achieving flexible cross-module routing.

C1 consciousness in human and nonhuman animals. C1 consciousness is an elementary property that is present in human infants as well as in animals. Nonhuman primates exhibit similar visual illusions, attentional blink, and central capacity limits as human subjects.

C2: Self-monitoring

Whereas C1 consciousness reflects the capacity to access external information, consciousness in the second sense (C2) is characterized by the ability to reflexively represent oneself ("metacognition")

A probabilistic sense of confidence. Confidence can be assessed nonverbally, either retrospectively, by measuring whether humans persist in their initial choice, or prospectively, by allowing them to opt out from a task without even attempting it. Both measures have been used in nonhuman animals to show that they too possess metacognitive abilities. By contrast, most current neural networks lack them: Although they can learn, they generally lack meta-knowledge of the reliability and limits of what has been learned...Magnetic resonance imaging (MRI) studies in humans and physiological recordings in primates and even in rats have specifically linked such confidence processing to the prefrontal cortex. Inactivation of the prefrontal cortex can induce a specific deficit in second-order (metacognitive) judgements while sparing performance on the first-order task. Thus, circuits in the prefrontal cortex may have evolved to monitor the performance of other brain processes.

Error detection: Reflecting on one’s own mistakes ...just after responding, we sometimes realize that we made an error and change our mind. Error detection is reflected by two components of electroencephalography (EEG) activity: the error-relativity negativity (ERN) and the positivity upon error (Pe), which emerge in cingulate and medial prefrontal cortex just after a wrong response but before any feedback is received...A possibility compatible with the remarkable speed of error detection is that two parallel circuits, a low-level sensory-motor circuit and a higher-level intention circuit, operate on the same sensory data and signal an error whenever their conclusions diverge. Self-monitoring is such a basic ability that it is already present during infancy. The ERN, indicating error monitoring, is observed when 1-year-old infants make a wrong choice in a perceptual decision task.

Meta-memory The term “meta-memory” was coined to capture the fact that humans report feelings of knowing, confidence, and doubts on their memories. ...Meta-memory is associated with prefrontal structures whose pharmacological inactivation leads to a metacognitive impairment while sparing memory performance itself. Metamemory is crucial to human learning and education by allowing learners to develop strategies such as increasing the amount of study or adapting the time allocated to memory encoding and rehearsal.

Reality monitoring. In addition to monitoring the quality of sensory and memory representations, the human brain must also distinguish self-generated versus externally driven representations - we can perceive things, but we also conjure them from imagination or memory...Neuroimaging studies have linked this kind of reality monitoring to the anterior prefrontal cortex

Dissociations between C1 and C2

According to our analysis, C1 and C2 are largely orthogonal and complementary dimensions of what we call consciousness. On one side of this double dissociation, self-monitoring can exist for unreportable stimuli (C2 without C1). Automatic typing provides a good example: Subjects slow down after a typing mistake, even when they fail to consciously notice the error. Similarly, at the neural level, an ERN can occur for subjectively undetected errors. On the other side of this dissociation, consciously reportable contents sometimes fail to be accompanied with an adequate sense of confidence (C1 without C2). For instance, when we retrieve a memory, it pops into consciousness (C1) but sometimes without any accurate evaluation of its confidence (C2), leading to false memories.

Synergies between C1 and C2 consciousness

Because C1 and C2 are orthogonal, their joint possession may have synergistic benefits to organisms. In one direction, bringing probabilistic metacognitive information (C2) into the global workspace (C1) allows it to be held over time, integrated into explicit long-term reflection, and shared with others...In the converse direction, the possession of an explicit repertoire of one’s own abilities (C2) improves the efficiency with which C1 information is processed. During mental arithmetic, children can perform a C2-level evaluation of their available competences (for example, counting, adding, multiplying, or memory retrieval) and use this information to evaluate how to best face a given arithmetic problem.

Endowing machines with C1 and C2

[Note: I am not abstracting this section as I did the above descriptions of consciousness. It describes numerous approaches rising above the level of most present day machines to making machines able to perform C1 and C2 operations.]

Most present-day machine-learning systems are devoid of any self-monitoring; they compute (C0) without representing the extent and limits of their knowledge or the fact that others may have a different viewpoint than their own. There are a few exceptions: Bayesian networks or programs compute with probability distributions and therefore keep track of how likely they are to be correct. Even when the primary computation is performed by a classical CNN, and is therefore opaque to introspection, it is possible to train a second, hierarchically higher neural network to predict the first one’s performance.

Concluding remarks

Our stance is based on a simple hypothesis: What we call “consciousness” results from specific types of information-processing computations, physically realized by the hardware of the brain. It differs from other theories in being resolutely computational; we surmise that mere information-theoretic quantities do not suffice to define consciousness unless one also considers the nature and depth of the information being processed.

We contend that a machine endowed with C1 and C2 would behave as though it were conscious; for instance, it would know that it is seeing something, would express confidence in it, would report it to others, could suffer hallucinations when its monitoring mechanisms break down, and may even experience the same perceptual illusions as humans. Still, such a purely functional definition of consciousness may leave some readers unsatisfied. Are we “over-intellectualizing” consciousness, by assuming that some high-level cognitive functions are necessarily tied to consciousness? Are we leaving aside the experiential component (“what it is like” to be conscious)? Does subjective experience escape a computational definition?

Although those philosophical questions lie beyond the scope of the present paper, we close by noting that empirically, in humans the loss of C1 and C2 computations covaries with a loss of subjective experience. For example, in humans, damage to the primary visual cortex may lead to a neurological condition called “blindsight,” in which the patients report being blind in the affected visual field. Remarkably, those patients can localize visual stimuli in their blind field but cannot report them (C1), nor can they effectively assess their likelihood of success (C2)—they believe that they are merely “guessing.” In this example, at least, subjective experience appears to cohere with possession of C1 and C2. Although centuries of philosophical dualism have led us to consider consciousness as unreducible to physical interactions, the empirical evidence is compatible with the possibility that consciousness arises from nothing more than specific computations.

Playing with proteins in virtual reality.

Much of my mental effort while I was doing laboratory research on the mechanisms of visual transduction (changing light into a nerve signal in our retinal rod and cone photoreceptor cells) was devoted to trying to visualize how proteins might interact with each other. I spent many hours using molecular model kits of color-coded plastic atoms one could plug together with flexible joints, like the Tinkertoys of my childhood. If I had only had the system now described by O'Connor et al! Have a look at the video below showing manipulating molecular dynamics in a VR environment,  and here is their abstract:

We describe a framework for interactive molecular dynamics in a multiuser virtual reality (VR) environment, combining rigorous cloud-mounted atomistic physics simulations with commodity VR hardware, which we have made accessible to readers (see isci.itch.io/nsb-imd). It allows users to visualize and sample, with atomic-level precision, the structures and dynamics of complex molecular structures “on the fly” and to interact with other users in the same virtual environment. A series of controlled studies, in which participants were tasked with a range of molecular manipulation goals (threading methane through a nanotube, changing helical screw sense, and tying a protein knot), quantitatively demonstrate that users within the interactive VR environment can complete sophisticated molecular modeling tasks more quickly than they can using conventional interfaces, especially for molecular pathways and structural transitions whose conformational choreographies are intrinsically three-dimensional. This framework should accelerate progress in nanoscale molecular engineering areas including conformational mapping, drug development, synthetic biology, and catalyst design. More broadly, our findings highlight the potential of VR in scientific domains where three-dimensional dynamics matter, spanning research and education.

Sampling molecular conformational dynamics in virtual reality from david glowacki on Vimeo.

Increasing despair among poor Americans.

A survey by Goldman et al. of more than 4,600 American adults conducted in 1995-1996 and in 2011-2014 suggests that among individuals of low socioeconomic status, negative affect increased significantly between the two survey waves, and life satisfaction and psychological well-being decreased:

Significance

In the past few years, references to the opioid epidemic, drug poisonings, and associated feelings of despair among Americans, primarily working-class whites, have flooded the media, and related patterns of mortality have been of increasing interest to social scientists. Yet, despite recurring references to distress or despair in journalistic accounts and academic studies, there has been little analysis of whether psychological health among American adults has worsened over the past two decades. Here, we use data from national samples of adults in the mid-1990s and early 2010s to demonstrate increasing distress and declining well-being that was concentrated among low-socioeconomic-status individuals but spanned the age range from young to older adults.

Abstract

Although there is little dispute about the impact of the US opioid epidemic on recent mortality, there is less consensus about whether trends reflect increasing despair among American adults. The issue is complicated by the absence of established scales or definitions of despair as well as a paucity of studies examining changes in psychological health, especially well-being, since the 1990s. We contribute evidence using two cross-sectional waves of the Midlife in the United States (MIDUS) study to assess changes in measures of psychological distress and well-being. These measures capture negative emotions such as sadness, hopelessness, and worthlessness, and positive emotions such as happiness, fulfillment, and life satisfaction. Most of the measures reveal increasing distress and decreasing well-being across the age span for those of low relative socioeconomic position, in contrast to little decline or modest improvement for persons of high relative position.

A fundamental advance in brain imaging techniques.

I want to pass on the abstract, along with a bit of text and two figures, from an article by Coalson, Van Essen, and Glasser that argues for a fundamental change is how functional cortical areas of the brain are recorded and reported.  They demonstrate that surface based parcellation is 3-fold more accurate than traditional volume based parcellations.:

Significance

Most human brain-imaging studies have traditionally used low-resolution images, inaccurate methods of cross-subject alignment, and extensive blurring. Recently, a high-resolution approach with more accurate alignment and minimized blurring was used by the Human Connectome Project to generate a multimodal map of human cortical areas in hundreds of individuals. Starting from these data, we systematically compared these two approaches, showing that the traditional approach is nearly three times worse than the Human Connectome Project’s improved approach in two objective measures of spatial localization of cortical areas. Furthermore, we demonstrate considerable challenges in comparing data across the two approaches and, as a result, argue that there is an urgent need for the field to adopt more accurate methods of data acquisition and analysis.

Abstract

Localizing human brain functions is a long-standing goal in systems neuroscience. Toward this goal, neuroimaging studies have traditionally used volume-based smoothing, registered data to volume-based standard spaces, and reported results relative to volume-based parcellations. A novel 360-area surface-based cortical parcellation was recently generated using multimodal data from the Human Connectome Project, and a volume-based version of this parcellation has frequently been requested for use with traditional volume-based analyses. However, given the major methodological differences between traditional volumetric and Human Connectome Project-style processing, the utility and interpretability of such an altered parcellation must first be established. By starting from automatically generated individual-subject parcellations and processing them with different methodological approaches, we show that traditional processing steps, especially volume-based smoothing and registration, substantially degrade cortical area localization compared with surface-based approaches. We also show that surface-based registration using features closely tied to cortical areas, rather than to folding patterns alone, improves the alignment of areas, and that the benefits of high-resolution acquisitions are largely unexploited by traditional volume-based methods. Quantitatively, we show that the most common version of the traditional approach has spatial localization that is only 35% as good as the best surface-based method as assessed using two objective measures (peak areal probabilities and “captured area fraction” for maximum probability maps). Finally, we demonstrate that substantial challenges exist when attempting to accurately represent volume-based group analysis results on the surface, which has important implications for the interpretability of studies, both past and future, that use these volume-based methods.

Some context from their introduction:

The recently reported HCP-MMP1.0 multimodal cortical parcellation (https://balsa.wustl.edu/study/RVVG, see the graphic below) contains 180 distinct areas per hemisphere and was generated from hundreds of healthy young adult subjects from the Human Connectome Project (HCP) using data precisely aligned with the HCP’s surface-based neuroimaging analysis approach. Each cortical area is defined by multiple features, such as those representing architecture, function, connectivity, or topographic maps of visual space. This multimodal parcellation has generated widespread interest, with many investigators asking how to relate its cortical areas to data processed using the traditional neuroimaging approach. Because volume-registered analysis of the cortex in MNI space is still widely used, this has often translated into concrete requests, such as: “Please provide the HCP-MMP1.0 parcellation in standard MNI volume space.” Here, we investigate quantitatively the drawbacks of traditional volume-based analyses and document that much of the HCP-MMP1.0 parcellation cannot be faithfully represented when mapped to a traditional volume-based atlas.

Here is a graphic from the parcellation analysis

And here is Figure 1 and its explanation from the Coalson et al. paper.

The figure shows a probabilistic maps of five exemplar areas spanning a range of peak probabilities. Each area is shown as localized by areal-feature–based surface registration (Lower, Center), and as localized by volume-based methods. One area (3b in Fig. 1) has a peak probability of 0.92 in the volume (orange, red), whereas the other four have volumetric peak probabilities in the range of 0.35–0.7 (blue, yellow). Notably, the peak probabilities of these five areas are all higher on the surface (Figure, Lower, Center) (range 0.90–1) than in the volume, indicating that MSMAll nonlinear surface-based registration provides substantially better functional alignment across subjects than does nonlinear volume-based registration.

Mindfulness training increases strength of right insula connections.

Sharp et al.(open source) suggest that:

The endeavor to understand how mindfulness works will likely be advanced by using recently developed tools and theory within the nascent field of brain connectomics. The connectomic framework conceives of the brain’s functional and structural architecture as a complex, dynamic network. This network view of brain function partly arose from the lack of support for highly selective, modular regions instantiating specialized functions. That is, large meta-analyses consisting mostly of univariate fMRI analyses disconfirm that, for example, the amygdala is exclusively selective for fear processing. Indeed, more fruitful mechanistic knowledge of how neural systems function may emerge from delineating how different regions communicate functionally across a range of environments, and by identifying the underlying structural connections that constrain such functional dynamics.

Their abstract, and a summary figure:

Although mindfulness meditation is known to provide a wealth of psychological benefits, the neural mechanisms involved in these effects remain to be well characterized. A central question is whether the observed benefits of mindfulness training derive from specific changes in the structural brain connectome that do not result from alternative forms of experimental intervention. Measures of whole-brain and node-level structural connectome changes induced by mindfulness training were compared with those induced by cognitive and physical fitness training within a large, multi-group intervention protocol (n = 86). Whole-brain analyses examined global graph-theoretical changes in structural network topology. A hypothesis-driven approach was taken to investigate connectivity changes within the insula, which was predicted here to mediate interoceptive awareness skills that have been shown to improve through mindfulness training. No global changes were observed in whole-brain network topology. However, node-level results confirmed a priori hypotheses, demonstrating significant increases in mean connection strength in right insula across all of its connections. Present findings suggest that mindfulness strengthens interoception, operationalized here as the mean insula connection strength within the overall connectome. This finding further elucidates the neural mechanisms of mindfulness meditation and motivates new perspectives about the unique benefits of mindfulness training compared to contemporary cognitive and physical fitness interventions.

Legend - Anatomical representation of tractography pathways between right insula and highly connected regions. Connections displayed (only corticocortical, here) comprised the top 80% connection strengths across all insula pathways. (A) Displays pre-training connections in right insula, which showed the greatest structural reorganization across mindfulness training. (B) Represents the same image as in (A) except at post-training.