Brain changes over our lifetime.

This video from The Economist is one of the best I have seen for a popular audience. Hopefully the basic facts presented are slowly seeping throughout our culture..

Comparing how generative AI and living organisms generate meaning suggests future direction for AI development

I want to pass on this open source opinion article in Trends in Cognitive Sciences by Karl Friston, Andy Clark, and other prominent figures who study generative models of sentient behavior in living organisms.  (They suggest a future direction for AI development that is very similar to the vision described in the previous MindBlog post, which described a recent article by Venkatesh Rao.) Here are the highlights and abstract of the article.

Highlights

• Generative artificial intelligence (AI) systems, such as large language models (LLMs), have achieved remarkable performance in various tasks such as text and image generation.
• We discuss the foundations of generative AI systems by comparing them with our current understanding of living organisms, when seen as active inference systems.
• Both generative AI and active inference are based on generative models, but they acquire and use them in fundamentally different ways.
• Living organisms and active inference agents learn their generative models by engaging in purposive interactions with the environment and by predicting these interactions. This provides them with a core understanding and a sense of mattering, upon which their subsequent knowledge is grounded.
• Future generative AI systems might follow the same (biomimetic) approach – and learn the affordances implicit in embodied engagement with the world before – or instead of – being trained passively.

Abstract

Prominent accounts of sentient behavior depict brains as generative models of organismic interaction with the world, evincing intriguing similarities with current advances in generative artificial intelligence (AI). However, because they contend with the control of purposive, life-sustaining sensorimotor interactions, the generative models of living organisms are inextricably anchored to the body and world. Unlike the passive models learned by generative AI systems, they must capture and control the sensory consequences of action. This allows embodied agents to intervene upon their worlds in ways that constantly put their best models to the test, thus providing a solid bedrock that is – we argue – essential to the development of genuine understanding. We review the resulting implications and consider future directions for generative AI.

Functional human brain tissue produced by layering different neuronal types with 3D bioprinting

A very important advance by Su-Chun Zhang and collaborators at the University of Wisconsin that moves studies of nerve cells connecting in nutrient dishes from two to three dimensions:  

Highlights

• •
  Functional human neural tissues assembled by 3D bioprinting
• •
  Neural circuits formed between defined neural subtypes
• •
  Functional connections established between cortical-striatal tissues
• •
  Printed tissues for modeling neural network impairment

Summary

Probing how human neural networks operate is hindered by the lack of reliable human neural tissues amenable to the dynamic functional assessment of neural circuits. We developed a 3D bioprinting platform to assemble tissues with defined human neural cell types in a desired dimension using a commercial bioprinter. The printed neuronal progenitors differentiate into neurons and form functional neural circuits within and between tissue layers with specificity within weeks, evidenced by the cortical-to-striatal projection, spontaneous synaptic currents, and synaptic response to neuronal excitation. Printed astrocyte progenitors develop into mature astrocytes with elaborated processes and form functional neuron-astrocyte networks, indicated by calcium flux and glutamate uptake in response to neuronal excitation under physiological and pathological conditions. These designed human neural tissues will likely be useful for understanding the wiring of human neural networks, modeling pathological processes, and serving as platforms for drug testing.

 

Graphical abstract

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Mental problems from early life adversity passed down three generations.

Early life adversity can result in emotional and behavioral problems throughout adulthood in both humans and mice. Battaglia et al. show than in mice this effect can persist through three generations. Exposure to the drug amiloride throughout the three generations can reverse this persistence of anxiety and pain sensitivity by inhidibint the increased activity of membrane ion channels that are its apparent cause. Here is their abstract:

Early-life adversities are associated with altered defensive responses. Here, we demonstrate that the repeated cross-fostering (RCF) paradigm of early maternal separation is associated with enhancements of distinct homeostatic reactions: hyperventilation in response to hypercapnia and nociceptive sensitivity, among the first generation of RCF-exposed animals, as well as among two successive generations of their normally reared offspring, through matrilineal transmission. Parallel enhancements of acid-sensing ion channel 1 (ASIC1), ASIC2, and ASIC3 messenger RNA transcripts were detected transgenerationally in central neurons, in the medulla oblongata, and in periaqueductal gray matter of RCF-lineage animals. A single, nebulized dose of the ASIC-antagonist amiloride renormalized respiratory and nociceptive responsiveness across the entire RCF lineage. These findings reveal how, following an early-life adversity, a biological memory reducible to a molecular sensor unfolds, shaping adaptation mechanisms over three generations. Our findings are entwined with multiple correlates of human anxiety and pain conditions and suggest nebulized amiloride as a therapeutic avenue.

18-month old humans discriminate moral violations from disobedient or unexpected events

Fascinating studies from Kassecker et al. (open source) have used multiple methods (eye-tracking, observations of expressive behaviors) to probe the developmental origins of human moral cognition by assessing infants’ ability to differentiate between prototypical harmful (moral) and harmless (conventional) violations:

Humans reason and care about ethical issues, such as avoiding unnecessary harm. But what enables us to develop a moral capacity? This question dates back at least to ancient Greece and typically results in the traditional opposition between sentimentalism (the view that morality is mainly driven by socioaffective processes) and rationalism [the view that morality is mainly driven by (socio)cognitive processes or reason]. Here, we used multiple methods (eye-tracking and observations of expressive behaviors) to assess the role of both cognitive and socioaffective processes in infants’ developing morality. We capitalized on the distinction between moral (e.g., harmful) and conventional (e.g., harmless) transgressions to investigate whether 18-mo-old infants understand actions as distinctively moral as opposed to merely disobedient or unexpected. All infants watched the same social scene, but based on prior verbal interactions, an actor’s tearing apart of a picture (an act not intrinsically harmful) with a tool constituted either a conventional (wrong tool), a moral (producing harm), or no violation (correct tool). Infants’ anticipatory looks differentiated between conventional and no violation conditions, suggesting that they processed the verbal interactions and built corresponding expectations. Importantly, infants showed a larger increase in pupil size (physiological arousal), and more expressions indicating empathic concern, in response to a moral than to a conventional violation. Thus, infants differentiated between harmful and harmless transgressions based solely on prior verbal interactions. Together, these convergent findings suggest that human infants’ moral development is fostered by both sociocognitive (inferring harm) and socioaffective processes (empathic concern for others’ welfare).

What Babies Know from zero to 1 year - core systems of knowledge

The journal Behavioral and Brain Sciences has sent out to reviewers the précis of a book, "What Babies Know" by Elizabeth S. Spelke, Harvard Psychology Dept. The abstract of her précis:

Where does human knowledge begin? Research on human infants, children, adults, and non- human animals, using diverse methods from the cognitive, brain, and computational sciences, provides evidence for six early emerging, domain-specific systems of core knowledge. These automatic, unconscious systems are situated between perceptual systems and systems of explicit concepts and beliefs. They emerge early in infancy, guide children’s learning, and function throughout life.

Spelke lists domain-specific core systems that are ancient, emerge early in life, and are invariant over later development. These deal with vision, objects, places, number, core knowledge, agents, social cognition, and language. Figures in the précis illustrate basic experiments characterizing the core systems. Motivated readers can obtain a PDF of the precis by emailing me.

Gender inequality is associated with differences between the brains of men and women

Sobering but not surprising analysis by Jugman et al.:  

Significance

Gender inequality is associated with worse mental health and academic achievement in women. Using a dataset of 7,876 MRI scans from healthy adults living in 29 different countries, we here show that gender inequality is associated with differences between the brains of men and women: cortical thickness of the right hemisphere, especially in limbic regions such as the right caudal anterior cingulate and right medial orbitofrontal, as well as the left lateral occipital, present thinner cortices in women compared to men only in gender-unequal countries. These results suggest a potential neural mechanism underlying the worse outcome of women in gender-unequal settings, as well as highlight the role of the environment in the brain differences between women and men.

Abstract

Gender inequality across the world has been associated with a higher risk to mental health problems and lower academic achievement in women compared to men. We also know that the brain is shaped by nurturing and adverse socio-environmental experiences. Therefore, unequal exposure to harsher conditions for women compared to men in gender-unequal countries might be reflected in differences in their brain structure, and this could be the neural mechanism partly explaining women’s worse outcomes in gender-unequal countries. We examined this through a random-effects meta-analysis on cortical thickness and surface area differences between adult healthy men and women, including a meta-regression in which country-level gender inequality acted as an explanatory variable for the observed differences. A total of 139 samples from 29 different countries, totaling 7,876 MRI scans, were included. Thickness of the right hemisphere, and particularly the right caudal anterior cingulate, right medial orbitofrontal, and left lateral occipital cortex, presented no differences or even thicker regional cortices in women compared to men in gender-equal countries, reversing to thinner cortices in countries with greater gender inequality. These results point to the potentially hazardous effect of gender inequality on women’s brains and provide initial evidence for neuroscience-informed policies for gender equality.

Multigenerational Impacts of Childhood Access to the Safety Net.

In an open source article in the January issue of the American Economic Review East et al. show that early life exposure to Medicaid enhances the next generation's health.

We examine multigenerational impacts of positive in utero health interventions using a new research design that exploits sharp increases in prenatal Medicaid eligibility that occurred in some states. Our analyses are based on US Vital Statistics natality files, which enables linkages between individuals' early life Medicaid exposure and the next generation's health at birth. We find evidence that the health benefits associated with treated generations' early life program exposure extend to later offspring. Our results suggest that the returns on early life health investments may be substantively underestimated.

How modern human brains are different from those of other hominids and chimps.

Work pointed to in the previous post continues to add to the list of behaviors once presumed to be unique to humans that have now been found in other animals (morality, having a ‘self’, etc.) Previous MindBlog posts (list, von Economo neurons etc. do search..) have noted emerging evidence for brain features unique to - or much more pronounced in - humans than other primates. Now Pinson et al. have found that a single amino acid change in the transketolase-like 1 (TKTL1) protein on production of basal radial glia, the workhorses that generate much of the neocortex, appears that the modern human has more neocortex to work with than the ancient Neanderthal did. Here is their abstract:

Neanderthal brains were similar in size to those of modern humans. We sought to investigate potential differences in neurogenesis during neocortex development. Modern human transketolase-like 1 (TKTL1) differs from Neanderthal TKTL1 by a lysine-to-arginine amino acid substitution. Using overexpression in developing mouse and ferret neocortex, knockout in fetal human neocortical tissue, and genome-edited cerebral organoids, we found that the modern human variant, hTKTL1, but not the Neanderthal variant, increases the abundance of basal radial glia (bRG) but not that of intermediate progenitors (bIPs). bRG generate more neocortical neurons than bIPs. The hTKTL1 effect requires the pentose phosphate pathway and fatty acid synthesis. Inhibition of these metabolic pathways reduces bRG abundance in fetal human neocortical tissue. Our data suggest that neocortical neurogenesis in modern humans differs from that in Neanderthals.

Intuitive physics learning in a deep-learning A.I. model

A fascinating open source article from Piloto et al. in Nature Human Behaviour that addresses a major shortcoming of current artifician intelligence systems:

‘Intuitive physics’ enables our pragmatic engagement with the physical world and forms a key component of ‘common sense’ aspects of thought. Current artificial intelligence systems pale in their understanding of intuitive physics, in comparison to even very young children. Here we address this gap between humans and machines by drawing on the field of developmental psychology. First, we introduce and open-source a machine-learning dataset designed to evaluate conceptual understanding of intuitive physics, adopting the violation-of-expectation (VoE) paradigm from developmental psychology. Second, we build a deep-learning system that learns intuitive physics directly from visual data, inspired by studies of visual cognition in children. We demonstrate that our model can learn a diverse set of physical concepts, which depends critically on object-level representations, consistent with findings from developmental psychology. We consider the implications of these results both for AI and for research on human cognition.

Molecular markers of eventual chronic diseases of aging are higher in young adults of lower socioeconomic status.

Sobering work from Shanahan et al.:  

Significance

The analysis of gene expression in peripheral whole blood of US young adults in their late 30s revealed socioeconomic status-based inequalities in the molecular underpinnings of the most common chronic conditions of aging. Associations involved immune, inflammatory, ribosomal, and metabolic pathways, and extra- and intra-cellular signaling. Body mass index was a plausible, sizable mediator of many associations. Results point to new ways of thinking about how social inequalities “get under the skin” and also call for renewed efforts to prevent chronic conditions of aging decades before diagnoses.

Abstract

Many common chronic diseases of aging are negatively associated with socioeconomic status (SES). This study examines whether inequalities can already be observed in the molecular underpinnings of such diseases in the 30s, before many of them become prevalent. Data come from the National Longitudinal Study of Adolescent to Adult Health (Add Health), a large, nationally representative sample of US subjects who were followed for over two decades beginning in adolescence. We now have transcriptomic data (mRNA-seq) from a random subset of 4,543 of these young adults. SES in the household-of-origin and in young adulthood were examined as covariates of a priori-defined mRNA-based disease signatures and of specific gene transcripts identified de novo. An SES composite from young adulthood predicted many disease signatures, as did income and subjective status. Analyses highlighted SES-based inequalities in immune, inflammatory, ribosomal, and metabolic pathways, several of which play central roles in senescence. Many genes are also involved in transcription, translation, and diverse signaling mechanisms. Average causal-mediated effect models suggest that body mass index plays a key role in accounting for these relationships. Overall, the results reveal inequalities in molecular risk factors for chronic diseases often decades before diagnoses and suggest future directions for social signal transduction models that trace how social circumstances regulate the human genome.

Third-party punishment by preverbal infants

From Kanakogi et al.:

Third-party punishment of antisocial others is unique to humans and seems to be universal across cultures. However, its emergence in ontogeny remains unknown. We developed a participatory cognitive paradigm using gaze-contingency techniques, in which infants can use their gaze to affect agents displayed on a monitor. In this paradigm, fixation on an agent triggers the event of a stone crushing the agent. Throughout five experiments (total N = 120), we show that eight-month-old infants punished antisocial others. Specifically, infants increased their selective looks at the aggressor after watching aggressive interactions. Additionally, three control experiments excluded alternative interpretations of their selective gaze, suggesting that punishment-related decision-making influenced looking behaviour. These findings indicate that a disposition for third-party punishment of antisocial others emerges in early infancy and emphasize the importance of third-party punishment for human cooperation. This behavioural tendency may be a human trait acquired over the course of evolution.

Testerone production in adult men is regulated by an adolescent period sensitive to family experiences.

 From Gettler et al.:

Significance

Testosterone influences how animals devote energy and time toward reproduction, including opposing demands of mating and competition versus parenting. Reflecting this, testosterone often declines in new fathers and lower testosterone is linked to greater caregiving. Given these roles, there is strong interest in factors that affect testosterone, including early-life experiences. In this multidecade study, Filipino sons whose fathers were present and involved with raising them when they were adolescents had lower testosterone when they later became fathers, compared to sons whose fathers were present but uninvolved or were not coresident. Sons’ own parenting behaviors did not explain these patterns. These results connect key social experiences during adolescence to adult testosterone, and point to possible intergenerational effects of parenting style.

Abstract

Across vertebrates, testosterone is an important mediator of reproductive trade-offs, shaping how energy and time are devoted to parenting versus mating/competition. Based on early environments, organisms often calibrate adult hormone production to adjust reproductive strategies. For example, favorable early nutrition predicts higher adult male testosterone in humans, and animal models show that developmental social environments can affect adult testosterone. In humans, fathers’ testosterone often declines with caregiving, yet these patterns vary within and across populations. This may partially trace to early social environments, including caregiving styles and family relationships, which could have formative effects on testosterone production and parenting behaviors. Using data from a multidecade study in the Philippines (n = 966), we tested whether sons’ developmental experiences with their fathers predicted their adult testosterone profiles, including after they became fathers themselves. Sons had lower testosterone as parents if their own fathers lived with them and were involved in childcare during adolescence. We also found a contributing role for adolescent father–son relationships: sons had lower waking testosterone, before and after becoming fathers, if they credited their own fathers with their upbringing and resided with them as adolescents. These findings were not accounted for by the sons’ own parenting and partnering behaviors, which could influence their testosterone. These effects were limited to adolescence: sons’ infancy or childhood experiences did not predict their testosterone as fathers. Our findings link adolescent family experiences to adult testosterone, pointing to a potential pathway related to the intergenerational transmission of biological and behavioral components of reproductive strategies.

Beginnings

The title of this post is the title of one of the mini-essays in a piece on my website, written 20 years ago, called "MINDSTUFF: BONBONS FOR THE CURIOUS USER." I re-discovered it while working on a lecture I'm giving this fall, and find the writing much more engaging than what I am currently generating!

 

BEGINNINGS

We are forever barred from recalling the buzzing cacophony that greeted our entry into this world. Our remembering brains had not formed, they had not begun to construct a world for themselves outside the womb. And yet, they had a very ancient kind of knowledge formed over millions of years. They knew to look for a face, they knew to direct muscles of the mouth to draw milk from a mother's breast. From a very rudimentary beginning repertoire they began fashioning a network of sensing and acting to finally generate the extraordinary machines that can read a page like this one.

In both the womb and with the growing baby, the story is a record of sensuality, of kinesthetic, visual, auditory, tasting and smelling histories that form themselves into a predictable order. A sense of past and of anticipation of the predictable future form a base non verbal imaged story line on which the layers of human language begin to build themselves. A smooth continuity informs the transformation of communication from gestures and simple sounds to strings of words with subjects, objects and verbs that form into stories about why, what, how, where. This transformation does not occur in feral children raised by surrogate animal parents, they appear to remain locked in the more present centered mental space of animals - a space that gives no flicker of reflectivity. The requirement is for not only our distinctively human genes but also a cultural context of human communication through gesture and language kept alive, altered, and transmitted by successive generations. We are tools of our our tools.

The programming of our brain regions central to social interactions is just as biological as the workings of a liver or kidney. It involves involuntary linkages of our primitive mammalian or limbic brain and its neuroendocrinology to status, sex, affiliation, power - mechanisms whose fundamental aspects we share with prairie voles and cichlid fish. Unique to humans is the self conscious confabulator or self-constructor that provides a new level of nudging, specification, control over these processes. It is this confabulator that generates what we take to be the world, what we take to be social sources of validation. All are in fact internal self creations that are assayed by their utility.

The human fear paradox: Affective origins of cooperative care

On the same morning last week that I read a NYTimes essay by Thomas Edsall "The Politics of Fear Show No Sign of Abating" I received an email from the journal Behavioral and Brain Science soliciting reviews on an upcoming article by Tobias Grossmann with an interesting hypothesis on why we humans are so fearful: "The human fear paradox: Affective origins of cooperative care." His 'fearful ape hypothesis' proposes that, in the context of the strong interdependence reflected in cooperative caregiving and provisioning unique to human great ape group life, heightened fearfulness was adaptive. Here I pass on the abstract of Grossmann's piece, and motivated readers can obtain the whole text from me.

Already as infants humans are more fearful than our closest living primate relatives, the chimpanzees. Yet heightened fearfulness is mostly considered maladaptive, as it is thought to increase the risk of developing anxiety and depression. How can this human fear paradox be explained? The fearful ape hypothesis presented herein stipulates that, in the context of cooperative caregiving and provisioning unique to human great ape group life, heightened fearfulness was adaptive. This is because from early in ontogeny fearfulness expressed and perceived enhanced care-based responding and provisioning from, while concurrently increasing cooperation with, mothers and others. This explanation is based on a synthesis of existing research with human infants and children, demonstrating a link between fearfulness, greater sensitivity to and accuracy in detecting fear in others, and enhanced levels of cooperative behaviors. These insights critically advance current evolutionary theories of human cooperation by adding an early-developing affective component to the human cooperative makeup. Moreover, the current proposal has important cultural, societal and health implications, as it challenges the predominant view in WEIRD societies that commonly construe fearfulness as a maladaptive trait, potentially ignoring its evolutionary adaptive functions.

Abnormal hemispheric interactions of Autism Spectrum Disorder present in 1st year of life.

From Rolison et al.:

Autism spectrum disorder (ASD) is characterized by atypical connectivity lateralization of functional networks. However, previous studies have not directly investigated if differences in specialization between ASD and typically developing (TD) peers are present in infancy, leaving the timing of onset of these differences relatively unknown. We studied the hemispheric asymmetries of connectivity in children with ASD and infants later meeting the diagnostic criteria for ASD. Analyses were performed in 733 children with ASD and TD peers and in 71 infants at high risk (HR) or normal risk (NR) for ASD, with data collected at 1 month and 9 months of age. Comparing children with ASD (n = 301) to TDs (n = 432), four regions demonstrated group differences in connectivity: posterior cingulate cortex (PCC), posterior superior temporal gyrus, extrastriate cortex, and anterior prefrontal cortex. At 1 month, none of these regions exhibited group differences between ASD (n = 10), HR-nonASD (n = 15), or NR (n = 18) infants. However, by 9 months, the PCC and extrastriate exhibited atypical connectivity in ASD (n = 11) and HR-nonASD infants (n = 24) compared to NR infants (n = 22). Connectivity did not correlate with symptoms in either sample. Our results demonstrate that differences in network asymmetries associated with ASD risk are observable prior to the age of a reliable clinical diagnosis.

Cannabis use during pregnancy correlates with cortisol, anxiety, aggression, and hyperactivity in young children.

Sobering results from Rompala et al.: 

Significance

Cannabis use is becoming more prevalent, including during developmentally sensitive periods such as pregnancy. Here we find that maternal cannabis use is associated with increased cortisol, anxiety, aggression, and hyperactivity in young children. This corresponded with widespread reductions in immune-related gene expression in the placenta which correlated with anxiety and hyperactivity. Future studies are needed to examine the effects of cannabis on immune function during pregnancy as a potential regulatory mechanism shaping neurobehavioral development.

Abstract

While cannabis is among the most used recreational drugs during pregnancy, the impact of maternal cannabis use (mCB) on fetal and child development remains unclear. Here, we assessed the effects of mCB on psychosocial and physiological measures in young children along with the potential relevance of the in utero environment reflected in the placental transcriptome. Children (∼3 to 6 y) were assessed for hair hormone levels, neurobehavioral traits on the Behavioral Assessment System for Children (BASC-2) survey, and heart rate variability (HRV) at rest and during auditory startle. For a subset of children with behavioral assessments, placental specimens collected at birth were processed for RNA sequencing. Hair hormone analysis revealed increased cortisol levels in mCB children. In addition, mCB was associated with greater anxiety, aggression, and hyperactivity. Children with mCB also showed a reduction in the high-frequency component of HRV at baseline, reflecting reduced vagal tone. In the placenta, there was reduced expression of many genes involved in immune system function including type I interferon, neutrophil, and cytokine-signaling pathways. Finally, several of these mCB-linked immune genes organized into coexpression networks that correlated with child anxiety and hyperactivity. Overall, our findings reveal a relationship between mCB and immune response gene networks in the placenta as a potential mediator of risk for anxiety-related problems in early childhood.

Volatile hexadecanal emitted by babies could make men more docile and women more aggressive

Interesting observations from Mishor et al.:

In terrestrial mammals, body volatiles can effectively trigger or block conspecific aggression. Here, we tested whether hexadecanal (HEX), a human body volatile implicated as a mammalian-wide social chemosignal, affects human aggression. 

Using validated behavioral paradigms, we observed a marked dissociation: Sniffing HEX blocked aggression in men but triggered aggression in women. Next, using functional brain imaging, we uncovered a pattern of brain activity mirroring behavior: In both men and women, HEX increased activity in the left angular gyrus, an area implicated in perception of social cues. HEX then modulated functional connectivity between the angular gyrus and a brain network implicated in social appraisal (temporal pole) and aggressive execution (amygdala and orbitofrontal cortex) in a sex-dependent manner consistent with behavior: increasing connectivity in men but decreasing connectivity in women. These findings implicate sex-specific social chemosignaling at the mechanistic heart of human aggressive behavior.

From the author's discussion:

....what behavioral setting could underlie selection for a body volatile that increases aggression in women but decreases it in men? Or in other words, what could be the ecological relevance of these results? In this respect, we call attention to the setting of infant rearing. Parents across cultures are encouraged to sniff their babies, an action that activates brain reward circuits in women. Our results imply that sniffing babies may increase aggression in mothers but decrease aggression in fathers. Whereas maternal aggression has a direct positive impact on offspring survival in the animal world, paternal aggression has a negative impact on offspring survival. This is because maternal aggression (also termed maternal defense behavior) is typically directed at intruders, yet paternal aggression, and more so nonpaternal male aggression, is often directed at the offspring themselves. If babies had a mechanism at their disposal that increased aggression in women but decreased it in men, this would likely increase their survival. With the hypothesis in mind that HEX provides babies with exactly such a mechanism, we first note that infant rearing is the one social setting where humans have extensive exposure to conspecific feces, a rich source of HEX. We also turned to a recently published analysis of baby-head volatiles, yet in contrast to our hypothesis, this report did not mention HEX. We turned to the authors of that report, who explained that the published analysis was not tuned to the near semivolatile range of HEX. With our question in mind, they (now coauthors T.U. and M.O.) sampled an additional 19 babies, using gas chromatography (GC) × GC–mass spectrometry, and observed that HEX is one of the most abundant baby-head volatiles...

Babbling bats

An interesting piece from Fernandez et al.:

Babbling is a production milestone in infant speech development. Evidence for babbling in nonhuman mammals is scarce, which has prevented cross-species comparisons. In this study, we investigated the conspicuous babbling behavior of Saccopteryx bilineata, a bat capable of vocal production learning. We analyzed the babbling of 20 bat pups in the field during their 3-month ontogeny and compared its features to those that characterize babbling in human infants. Our findings demonstrate that babbling in bat pups is characterized by the same eight features as babbling in human infants, including the conspicuous features reduplication and rhythmicity. These parallels in vocal ontogeny between two mammalian species offer future possibilities for comparison of cognitive and neuromolecular mechanisms and adaptive functions of babbling in bats and humans.

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

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

Significance

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

Abstract

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