“Now Is the Time of Monsters”

I pass on links to two articles in the same vein, one by Ezra Klein, the other by Ventkatesh Rao, with Klein noting how we are facing four epoch-changing events, any one of which could utterly change the world we have know for the past 70 years.  Both articles cite the writing of the Marxist Italian philosopher Antonio Gramsci, who wrote a well know sentence usually translated as “The old world is dying, and the new world struggles to be born: Now is the time of monsters.”  Rao offers the following graphic of the transition:

 

Klein points to:
1. Authoritarian consolidation across the world and the death of democracies.
2. The poorly understood large language models of AI exponentially approaching problem solving and general intelligence capabilities that may exceed human abilities
3. whose hardware has voracious energy requirements that act against curing the global warming that is irreversibly changing our planet.
4.  Population collapse due to lowering birthrates presenting a larger immediate threat to civilization than global warming.

And Rao dissects the fine structures of the interregnum noted by Gramsci's original phrase "...in this interregnum a great variety of morbid symptoms appear."  Rao notes "an interesting idea that a "monster" is an instance of "morbid symptoms" appearings in either or both of the two building blocks of "world" - systems of rules and special people."

 

Tokens of sanity

I repeat my September 29, 2024 "Tokens of sanity" post with a few edits: 

  

-Being the calm space in which nothing can hurry

-A animal body that can dissociate itself from the word cloud and emotional reactivities of self and other selves.

-A courteous guest in its own body and when with others, owning its own experience and letting others own theirs.

-Favoring reflectivity over reactivity, caressing novelty

-Clinging to nothing, the current self being a passing fantasy

-Letting each moment be what it is, not what it should be

-A blip in the flow of cosmic time

Everything we experience comes from inside

I pass on this cryptic paragraph from my personal journal:

Everything we experience is coming from inside us - our illusion of having a self, our sense of agency. This includes attributing causal agency to others, as in  'they are making me do this,’  This 'error' allows individuals in a kinship group or tribe who share the same error to form an imaginary 'we' hive mind supporting unified action. The higher metacognitive stance is to participate when necessary in the group illusion while maintaining clarity on the fact that the actual agency is within oneself.

 

Regions of our brains making multiple predictions of others' actions.

I want to point to an excellent review and summary by Lin and Wittmann in Trends in Neurosciences of work by Ma et al. in J.Neurosci. (both are open source texts) that deal with the role of evolutionarily younger primate cortical brain regions - such as posterior cingulate cortex and medial preforntal cortex - in social belief inference. Such combined modeling and imaging studies are revealing in greater and greater detail the anatomical correlates of social cognition strategies.  Here is the significance statement from the Ma et al. article:

In daily life, to adjust our decisions, we constantly predict others’ choices, but the inherent uncertainty means we face multiple scenarios for different choices by others. Using computational modeling-based fMRI, we identified a network in three-stage computations for such decision-making. Amygdala signals represent predictions of others’ choices. These signals then interact with the posterior cingulate cortex and dorsolateral prefrontal cortex, representing the decision variables with the prediction of others’ likely and unlikely choices, respectively. Finally, these signals modulate the medial prefrontal cortex, influencing our final choices. These pivotal variables and their corresponding brain signals play a fundamental role in a broad range of social cognitive processes. Our findings shed light on underlying mechanisms for complex social interactions in human behavior.

How much does language shape our thinking?

I want to pass on this link to Manvir Singh's article in The New Yorker which has the title of this post.  I enjoyed reading the article. 

Also, I've been comparing the responses of LLMs  (Chat GPT 4o, Perplexity, Anthropic, Gemini) to the very simple prompt:  "Please summarize the following essay with the title: ......".  I'm frequently finding the Perplexity response most useful. It provides a list of steps it is following and HTML links to the sources it is using.  I estimate it would take me at least 30 min to prepare a summary of similar quality to the following Perplexity summary of the Singh article:

The essay explores the profound question of how language shapes human thought, examining cultural, cognitive, and social dimensions of this relationship.

Key Themes and Arguments:

 1. Language as Empowerment: The essay opens with the story of Angrezi Devi, the “Goddess English,” created by Dalit writer Chandra Bhan Prasad in India to symbolize the liberating potential of English for marginalized communities. Prasad argues that English offers Dalits a pathway out of caste oppression, contrasting it with Hindi, which he sees as reinforcing caste biases. 

2. Global Dominance of English: English is highlighted as the world’s dominant lingua franca, used in international institutions and pursued globally for its economic and social opportunities. However, its spread is accompanied by concerns about cultural homogenization and “cognitive hegemony,” where English’s structures might shape thought in ways aligned with Western norms. 

3. Linguistic Relativity and Whorfianism: The essay revisits Benjamin Lee Whorf’s theory that language influences thought, contrasting “strong Whorfianism” (language determines thought) with “weak Whorfianism” (language subtly shapes cognition). Examples include studies showing how Russian speakers distinguish shades of blue more effectively than English speakers due to their language’s lexical distinctions. 

 4. Cultural Variations in Cognition: Research reveals striking differences in how languages shape perceptions of time, space, and sensory experiences. For instance: • Aymara speakers conceptualize time with the past “in front” and the future “behind,” reflecting their linguistic metaphors. • Jahai speakers possess a rich vocabulary for smells, unlike English speakers who struggle to describe odors abstractly. 

5. Critiques and Nuances: While critics like Steven Pinker dismiss extreme Whorfian claims as overblown, recent research supports nuanced effects of language on cognition. Language influences attention, memory, and problem-solving in culturally specific ways but does not wholly dictate thought. 

6. Language Evolution and Adaptation: The essay emphasizes that languages evolve to reflect local contexts. For example, Indian English integrates native linguistic features like honorifics and unique phrases, showing how English adapts to diverse cultural environments rather than imposing uniformity.

Conclusion:
The essay concludes that while language profoundly influences thought, this relationship is dynamic and bidirectional. Languages shape how we perceive the world, but human cognition also transforms languages over time. Linguistic diversity is celebrated as a testament to humanity’s ingenuity and adaptability.

The birth of aspirational multiethnic populism

I have pulled some clips from an excellent substack piece by Yascha Mounk to cement and archive his main points for myself and also pass on to MindBlog readers.  He points out that Trump won a more convincing victory in 2024 than 2016…

…by doing what academics are supposed to be expert in: recognizing that the popular understanding of some concept—in this case, populism—is actually constituted by two elements which are logically separable. In his more recent incarnation, Trump has held on to his disdain for longstanding norms and his populist belief in the unfettered prerogative of the majority. But he has also made more explicit than in the past that his political vision is open to supporters from every ethnic and religious group—and has been very shrewd in courting them with an aspirational vision of America.

Though the term is much-overused and often misapplied, the concept of populism remains the most accurate frame for understanding his actions: He believes that, as the rightful voice of the people, he should not suffer any artificial restrictions on his actions—whether by unwritten norms or by explicit limits on the powers of a president.
 
He took evident pleasure in the fact that he owes his victory in large part to his growing popularity among Hispanics, Asian-Americans and African-Americans. He explicitly thanked those demographic groups for their support. He even invoked Martin Luther King Jr., promising to turn his dream into a reality.

For the most part, the executive orders Trump announced in his Second Inaugural are tailor-made to support this vision. His promise to restore order to American cities will resonate among the poorer and more diverse segments of his electorate who are the prime victims of urban crime. His promise to restore free speech is broadly popular among voters without fancy degrees who feel that elites are using their arbitrary moral codes and linguistic conventions as cudgels to wield against them at will.

Indeed, what is most striking about Trump’s vision is that, for all of its exaggerated laments about the dilapidated state of America, it is profoundly aspirational. His paean to colorblindness and meritocracy resonates among many Hispanic and Asian-American voters who feel much more secure in their membership in the American mainstream than Democratic invocations of the distorting category of “people of color” would suggest. And his promise to plant the American flag on Mars recalls the collective ambition and grandeur of the 1960s space race.

The received wisdom for the last decade has been that Trump has made his political home among the “losers of globalization.” …his voters supposedly felt that they were stuck in a long line that did not budge, with the wrong kinds of people—notably women and ethnic minorities—cutting in line.

That was and likely remains Trump’s appeal for one part of his electorate. But another part of his base—just as important—has a very different view of America. Hailing from groups that had once been banished to the fringes of American society or have immigrated more recently, they don’t want to return to a supposedly golden past.

On the contrary, they are optimistic about the future and embrace entrepreneurial values precisely because they feel that their hard work is starting to pay off. They don’t picture themselves as standing in a long, static line to enter a destination they covet; rightly or wrongly, they believe that the doors to it would be wide open if gatekeepers—from journalists to Democrats to elites self-servingly insisting on outdated norms—hadn’t cruelly decided to bar their way.

There are good reasons to remain concerned about this version of populism. Democracies do in fact need rules and norms. When the separation of powers goes out of the window, bad policies and perilous constitutional crises usually follow suit. And, being capable of attracting genuine support among a much broader cross-section of the population than most observers recognized until recently, Trump’s brand of populism is more likely to succeed in transforming the country’s political culture this time around.

…the first step in understanding any political movement lies in taking seriously the sources of its popularity. Trump has forged a brand of populism that has wide appeal and makes big promises about the future. If you want to use a suitably academic term, you might call it aspirational, multiethnic populism. Therein lies the power, the promise and the peril posed by Trump’s second presidency.
 

Poof! I'm 15-20 years younger...

A Wall Street Journal article recently pointed me to two websites using AI to estimate one's biological age. So....I took a selfie of my 82 year old face with my iPhone to get novoslabs.com's and facialage.com's estimates that I am 63 and 67 years old, respectively!  Now, two weeks later, I have asked my stable of bots (GPT 4o, Perplexity, etc) for other vendors providing the same service and found four more sites to try. Here are the reactions of all six sites to a further selfie I just took with my iPhone:

https://novoslabs.com/faceage/#test  reported the same result, facial age 63 years old, , in reaction to the new picture, and also reported Eye Age (54 years), Eye Bags (72/100) and Facial Wrinkles (18/100)

https://www.facialage.com/   reported 66 years old,  close to the 67 years old estimate of the previous selfie

reports from other apps:

https://age.toolpie.com/       66 years old

https://faceagecalculator.com/   51  years old 

https://howolddoyoulook.com/    58 years old

https://www.howolddoilook.io/  29  years old

All of the 60-something estimates feel in the right ball park, but heading below that gets into fantasy territory. 

 

The Neurobiology of Aging

I want to point to the Jan. 8 issue of the journal "Neuron" which is largely devoted to the neuroscience of aging.  A number of its review articles are open source. The writing is mostly gibble-gabble, but many useful references can be extracted, particularly on interactions between the immune and nervous systems relevant to aging. 

The origin of color categories

Garside et al. make observations suggesting that cognitive mechanisms such as language are required for the expression of consensus color categories.

Significance

A hallmark of intelligence is the use of concepts. Are people innately equipped with concepts? Prior research has addressed the question using color, because color is experienced categorically: color categories reflect concepts of color. This study tested for color categories in macaque monkeys, a species with the same visual-encoding systems as humans. If color categories are innate products of vision, monkeys should have them. The data were analyzed with sensitive computational models, which showed that monkeys do not have consensus color categories, unlike humans. One monkey had a private color category, suggesting that the capacity to form color categories is innate. The results imply that cognitive mechanisms such as language are required for the expression of consensus color categories.

Abstract

To what extent does concept formation require language? Here, we exploit color to address this question and ask whether macaque monkeys have color concepts evident as categories. Macaques have similar cone photoreceptors and central visual circuits to humans, yet they lack language. Whether Old World monkeys such as macaques have consensus color categories is unresolved, but if they do, then language cannot be required. If macaques do not have color categories, then color categories in humans are unlikely to derive from innate properties of visual encoding and likely to depend on cognitive abilities such as language that differ between monkeys and humans. We tested macaques by adapting a match-to-sample paradigm used in humans to uncover color categories from errors in matches, and we analyzed the data using computational simulations that assess the possibility of unrecognized distortions in the perceptual uniformity of color space. The results provide evidence that humans have consensus cognitive color categories and macaques do not. One animal showed evidence for a private color category, demonstrating that monkeys have the capacity to form color categories even if they do not form consensus color categories. Taken together, the results imply that consensus color categories in humans, for which there is ample evidence, must depend upon language or other cognitive abilities.

 

Is critical race theory an inversion of history?

John Ellis, who says yes, is a professor emeritus of German literature at the University of California, Santa Cruz (and author of “A Short History of Relations Between Peoples: How the World Began to Move Beyond Tribalism.” )

I've decided to share his recent WSJ essay to archive them for myself and interested MindBlog readers, even though it is overly simplistic in its emphasis on the virtues of the Anglosphere versus its vices. His basic argument is that so-called "White Privilege" of the Anglosphere is what originally freed us from a universal tribalism in which everyone, by today's standards, was racist. It did this by developing the idea of a common humanity.  Here is the text: 

It’s a tribute of sorts to critical race theory’s success that the Trump administration will make its eradication a priority. The Biden administration had quietly implemented policies throughout the federal government based on this theory, and it is being taught in colleges and schools throughout the country. It has overrun much of the corporate world, and it has even secured a place in the training of many professions. The accusations made in closed training sessions are astonishingly venomous: Arrogant white supremacy is ubiquitous; white rage results when that supremacy is challenged; whites hold money and power because they stole it from other races; systemic racism and capitalism keep the injustices going.

All of this is based on categorically false assumptions about the past. We need only look at how the modern idea of our common humanity originated and developed to see that critical race theory has everything backward. A realistic history tells us that the thinkers and engineers of the Anglosphere, principally England and the U.S., are the heroes, not the villains, of this story, while the rest were laggards, not leaders.

For most of recorded history, neighboring peoples regarded each other with apprehension if not outright fear and loathing. Tribal and racial attitudes were universal. That’s a long way from the orthodoxy of our own time, which holds that we are all one human family. Before that consensus arose, a charge of racism made no sense. By today’s standards, everyone was racist.

It’s not hard to understand why tribalism once reigned everywhere. Without modern transportation and communication, most people knew nothing about other societies. What contact there was between different peoples often involved warfare, and that made everyone fear strangers. The insecurity of life in earlier times added to this anxiety. Protections we now enjoy didn’t exist: policing, banking, competent medical care, social safety nets. The supply of food was uncertain before trucks and refrigeration. In a dangerous world people clung to their own kind for safety, and that was a natural and even necessary attitude.

How did we get from this mindset to the idea of a common humanity? The practical impediments to the world’s peoples getting to know and eventually respect each other were largely removed by British and American engineers. They invented the steam engine, then used it to develop the first railways. They followed this by inventing and massproducing cars, trucks and finally airplanes. They pioneered radio, television, films, newspapers and the internet. The result was that ignorance of other peoples was turned around.

But in the 18th century the British did something even more important: They began to develop our modern outlook on race.

Why Britain? Liberalizing political developments beginning with the Magna Carta and the first representative Parliament, called by Simon de Montfort, fostered greater liberty for the British subject. Liberty led to increasing prosperity, and prosperity to a rapid increase in literacy. Widespread literacy created the first large reading public: By the beginning of the 18th century, dozens of newspapers and periodicals were being published in Britain. An extensive reading public allowed public opinion to become a powerful force, and that set the stage for manifestos and petitions, even campaigns about matters that offended the public’s conscience.

A series of British writers began to promote ideas about the conduct of life and the role of government. Among the most important was John Locke, who argued that every human life had its own rationale, none being created for the use of another. Another was David Hume, who wrote that all men are nearly equal “in their mental power and faculties, till cultivated by education.” These and many others were launching what would become the modern consensus that we are all one human family. The idea gained ground so quickly that in Britain, and there alone, a powerful campaign to abolish slavery arose. By the end of the 18th century that campaign was leading to prohibitions in many parts of the Anglosphere, while Africa and Asia remained as tribalist and racist as ever.

As this idea took hold it made the British see their empire differently. Like other European countries, Britain had initially sought empire to strengthen its position in the world—others would add territory if Britain didn’t, and Britain would be weakened. But if the peoples of the British Empire were one human family, how could some be subordinate to others? The British began to consider themselves responsible for the welfare and development of their subject peoples, and for giving them competent administration before they had learned to provide it themselves. That change inevitably led to the dissolution of empire, and to a consensus that the time for empires (of which there had been hundreds) was over. The world’s most influential anti-imperialists were British. The idea of a common humanity spread across the globe as the power and influence of the Anglosphere grew.

First, this new ideology spread throughout the quarter of the globe’s peoples that were in the British Empire, where different races were learning to live and work together. Next, the Anglosphere’s cultural influence went worldwide as Britain’s industrial revolution set off a culture of innovation that resulted in a universal civilization— that is, modernity. As that way of life spread throughout the world, it carried with it the idea of a common humanity. There’s a simple explanation for what critical race theory calls “white privilege.” Because the Anglosphere developed prosperous modernity and gave it to the world, English-speakers were naturally the first to enjoy it. People initially outside that culture of innovation are still catching up. Asians and Asian-Americans have done this with great success, but critical race theory impedes the progress of other groups by persuading them to demonize the people who created the modern values they have adopted. It betrays those values by stoking racial hatred. Critical race theory tells us that all was racial harmony until racist Europeans disturbed it, but the truth is rather that all was tribal hostility until the Anglosphere rescued us.

Breathing during sleep orchestrates hippocampal nested sleep oscillations underlying memory consolidation

A fascinating correlation is found by Sheriff et al.  Their abstract:

Nested sleep oscillations, emerging from asynchronous states in coordinated bursts, are critical for memory consolidation. Whether these bursts emerge intrinsically or from an underlying rhythm is unknown. Here, we show a previously undescribed respiratory-driven oscillation in the human hippocampus that couples with cardinal sleep oscillations. Further, breathing promotes nesting of ripples in slow oscillations, together suggesting that respiration acts as an intrinsic rhythm to coordinate synchronization of sleep oscillations, providing a unique framework to characterize sleep-related respiratory and memory processes.

Predictive coding for social perception

Rittershofer et al. introduce a special issue of Neuroscience and Biobehavioral Reviews titled "Neurobiology of Social Interactions Across Species."  Here is the first part of that introduction:

Perception cannot rely solely on bottom-up processes, whereby patterns of receptor stimulation are passed up the hierarchy to generate a corresponding awareness. Such bottom-up processes would always generate experiences that are out-of-date and saturated by noise. Predictive processes are thought to play a key role in overcoming these problems, allowing us to generate best guesses concerning the likely sensorium, and highlighting quickly when the world is not as we expect. Action provides a crucial predictive source and a mechanism for us to resolve uncertainty and surprise, but further complicates our understanding due to further predictive cues and continuous change of sensory input. Another agent who can also change the world and who we seek to understand adds another layer of complexity yet. How can we understand the predictive mechanisms supporting social interaction and understanding, with such a multitude of moving and interacting components? In this special issue, Keysers et al. (2024) outline how predictive coding can be applied to understanding the actions and emotions of others, with Mayo and Shamay-Tsoory (2024) discussing how these mutual predictions might shape social learning. They suggest that such social learning might be supported by interbrain synchronization and Antonelli et al. (2024) discuss the critical role of emotion in shaping these multibrain dynamics.

 

While it is clearly crucial that we understand the nature of the mechanisms underlying social interactions, we wish to highlight the challenges of this complexity for scientific progress. Particularly, how to find ways to properly test, refute, and improve our models, when the assumed supporting mechanisms are so complex.

 

How predictions shape neural processing is thought to differ across space and time, even for processing of the simplest (non-social; static) elements of our environment. Keysers et al. (2024) highlight the assumed neural interactions across cortical layers, such that predictions are passed down the hierarchy to hypothesis units in deep (and perhaps superficial) cortical layers, input arrives in middle layers, and error signals are calculated and represented in superficial layers. This idea is supported by recent 7 T MRI work from our lab demonstrating increased decoding of predicted Gabor orientations in deep layers of primary visual cortex, with an advantage for unpredicted orientations in superficial layers (Thomas et al., 2024). Recent evidence suggests opposing influences at the temporal level as well (McDermott et al., 2024). This electroencephalography (EEG) study found that early perceptual processing is biased towards what we expect (< 200 ms; optimizing veridicality) with the advantage flipping in later timeranges (> 200 ms; optimizing informativeness – in line with the opposing process account proposed in Press et al., 2020). Building testable mechanistic accounts of these interactions across time and space – even for the simple perception of deterministic sequences of Gabor patches – represents a continued puzzle for future work.

 

In the social domain, the stimuli are by their nature highly complex and dynamic (Keysers et al., 2024). Therefore, these above interactions across space and time must be continuously updated. Despite this complexity, there is some evidence cited by Keysers et al. (2024) inline with the above laminar conclusions in simpler environments. Specifically, there is increased deep-layer information about observed actions in parietal cortex when presented in a predictable order, mediated via feedback connections (from premotor cortex). Social domains also yield multiple sources of prediction about the self and other (Mayo and Shamay-Tsoory, 2024) and we must determine how we weight the precision, or reliability, of these different sources, as well as how we render information about the self and other separable. Is this achieved by different cell populations coding information about the self and other (Mayo and Shamay-Tsoory, 2024)? Or could mechanisms similar to those proposed to distinguish products of imagination from reality (similarly internal vs external sources), also help in determining the information source in social situations?

 

Social predictions might be supported by interbrain synchronization (measured via hyperscanning), as discussed by Mayo and Shamay-Tsoory (2024); focus on social learning) and Antonelli et al. (2024); focus on emotion). We propose that one key challenge for this approach is determining the role played by different event-related inputs and responses in the effects: Interpretation of hyperscanning data is plagued by the problem that brains will be “in synch” if two individuals are either perceiving the same events or producing the same behaviour. The brain’s responses to moving our arm or looking at a face are remarkably similar across individuals, such that if two of us perceive or produce the same event our neural response will be matched. Fluctuations in synchronisation according to, e.g., dominance of individuals or levels of excitement on stage, could be determined by fluctuations in whether we attend to, or produce, the same events. It is crucial to understand the fascinating influence of these effects on synchronisation.

 

 

Romantic Relationships Matter More to Men than to Women

I pass on the abstract of an interesting manuscript that has been accepted by Behavioral and Brain Science, by Wahring et al. :

Women are often viewed as more romantic than men, and romantic relationships are assumed to be more central to the lives of women than to those of men. Despite the prevalence of these beliefs, some recent research paints a different picture. Using principles and insights based on the interdisciplinary literature on mixed-gender relationships, we advance a set of four propositions relevant to differences between men and women and their romantic relationships. We propose that relative to women: (a) men expect to obtain greater benefits from relationship formation and thus strive more strongly for a romantic partner, (b) men benefit more from romantic relationship involvement in terms of their mental and physical health, (c) men are less likely to initiate breakups, and (d) men suffer more from relationship dissolution. We offer theoretical explanations based on differences between men and women in the availability of social networks that provide intimacy and emotional support. We discuss implications for friendships in general and friendships between men and women in particular.

Children as agents of cultural adaption

When I scroll through some of the social medial sites (Instagram, Tik-Tok, X, YouTube, etc.) used by today's teenagers and their influencers I feel I am visiting another planet whose denizens have brains that process reality in an entirely different way from my 82 year old model. They have much shorter attention spans that remain focused on one context for only a few seconds  before flitting on. What kind of culture does this peer group inhabit?  This issue is addressed in a manuscript  by Levy and Amir accepted by Behavioral and Brain Science that one can download and read through.   Here is their abstract:

The human capacity for culture is a key determinant of our success as a species. While much work has examined adults’ abilities to create and transmit cultural knowledge, relatively less work has focused on the role of children (approx. 3-17 years) in this important process. In the cases where children are acknowledged, they are largely portrayed as acquirers of cultural knowledge from adults, rather than cultural producers in their own right. In this paper, we bring attention to the important role that children play in cultural adaptation by highlighting the structure, function, and ubiquity of the large body of knowledge produced and transmitted by children, known as peer culture. Supported by evidence from diverse disciplines, we argue that children are independent producers and maintainers of these autonomous cultures, which exist with regularity across diverse societies, and persist despite compounding threats. Critically, we argue peer cultures are a source of community knowledge diversity, encompassing both material and immaterial knowledge related to geography, ecology, subsistence, norms, and language. Through a number of case studies, we further argue that peer culture products and associated practices — including exploration, learning, and the retention of abandoned adult cultural traits — may help populations adapt to changing ecological and social conditions, contribute to community resilience, and even produce new cultural communities. We end by highlighting the pressing need for research to more carefully investigate children's roles as active agents in cultural adaptation.

How our brain networks are reconfigured by a cortisol increase 30-45 min after our waking.

 Zeng et al.  offer a fascinating account of how the rise in our body cortisol levels 30-45 min after waking orchestrates a reconfiguration of brain networks underlying working memory, emotional reguation and executive functioning.  I pass on the introductory paragraph of the article, followed by the article's abstract. (Motivated readers can obtain a PDF of the entire paper with graphics by emailing me.)

The introductory paragraph: 

For centuries, scientists have sought to unravel how the brain and endocrinal signals work in concert to support ever-changing cognitive and environmental demands. In theory, to sustain a dynamic equilibrium between internal milieu and external challenges, the brain and endocrinal signals actively engage in allocation of neural resources to prepare for the upcoming challenges (1, 2). Such active process has been conceptualized as “allostasis” and is believed to serve as one key principle of how neural and endocrinal signals interplay to support nuanced emotional and executive functions, though the underlying mechanisms remain largely elusive. Among endocrinal signals, the stress hormone cortisol plays a critical role in mobilizing energy supply for brain, cognition, and emotion (1, 3, 4). The cortisol awakening response (CAR), in particular, as a natural rise of cortisol through activation of the hypothalamus–pituitary–adrenal (HPA) axis within 30 to 45 min after morning awakening, is superimposed upon the circadian rhythm of cortisol secretion and is more than the mere release of cortisol (5–7). The CAR has been thought to support anticipation of a day’s most reliable stressor—waking up, mobilizing the energy to daily activities (8–10) and proactively modulates human emotion and cognition (11–13). Such proactive effects are reminiscent of a potential mediator of allostasis (1, 14). Although the CAR proactive effects are well documented at a behavioral level, our understanding of the underlying neurobiological mechanisms still remains in its infancy.

The article's abstract:

Emotion and cognition involve an intricate crosstalk of neural and endocrine systems that support dynamic reallocation of neural resources and optimal adaptation for upcoming challenges, an active process analogous to allostasis. As a hallmark of human endocrine activity, the cortisol awakening response (CAR) is recognized to play a critical role in proactively modulating emotional and executive functions. Yet, the underlying mechanisms of such proactive effects remain elusive. By leveraging pharmacological neuroimaging and hidden Markov modeling of brain state dynamics, we show that the CAR proactively modulates rapid spatiotemporal reconfigurations (state) of large-scale brain networks involved in emotional and executive functions. Behaviorally, suppression of CAR proactively impaired performance of emotional discrimination but not working memory (WM), while individuals with higher CAR exhibited better performance for both emotional and WM tasks. Neuronally, suppression of CAR led to a decrease in fractional occupancy and mean lifetime of task-related brain states dominant to emotional and WM processing. Further information-theoretic analyses on sequence complexity of state transitions revealed that a suppressed or lower CAR led to higher transition complexity among states primarily anchored in visual-sensory and salience networks during emotional task. Conversely, an opposite pattern of transition complexity was observed among states anchored in executive control and visuospatial networks during WM, indicating that CAR distinctly modulates neural resources allocated to emotional and WM processing. Our findings establish a causal link of CAR with brain network dynamics across emotional and executive functions, suggesting a neuroendocrine account for CAR proactive effects on human emotion and cognition.