Ketamine increases neuroplasticity in female mice but not in males

Amazing stuff! Good news!

"Doctors use ketamine on patients as general anesthesia before surgery. They also prescribe it in low doses for pain management, and more recently, it’s been used for treatment-resistant depression where other drugs have failed.

It works by dampening communication between brain cells. But a new study reveals that its effects on the brain are different in male and female mice. This insight—if reproduced in humans—could change the way we test the efficacy of drugs and unlock better treatments for depression. ...

discovered that when female mice are recovering from a single ketamine sedation, their brains become more active than their male counterparts, specifically their microglia. These specialized brain cells began reaching out with their branch-like arms to intermingle with surrounding brain cells. This increased activity led to the removal of the extracellular matrix—the proteins and molecules surrounding, supporting, and giving structure to cells—and created space that allowed new synapses to form and remodel the neural network, thereby increasing neuroplasticity. Researchers didn’t observe this behavior in male mice. ...

Neuroplasticity is a delicate balance: too much or too little have both been linked to neuropsychiatric disorders. ..."

From the abstract:

"Anesthesia recovery is critical for resuming normal physiological and neuronal functions; however, the mechanisms involved remain elusive.

Here, we identify a female-selective corticosterone-mediated microglia-neuron interaction during ketamine anesthesia recovery, absent in males.

This microglia-neuron interaction induces plastic and functional neuronal changes, as evidenced by increased mEPSC frequency, which was occluded upon microglia depletion.

We showed that this process is driven through up-regulation of the stress-responsive co-chaperone Fkbp5 mRNA and its protein, Fkbp51, in female microglia. Fkbp5/Fkbp51 is a key intermediary in a corticosteroid-induced stress response, and its involvement points toward a critical interface between endocrine signaling and microglia.

To counteract the observed ketamine anesthesia-mediated increase in blood corticosterone during recovery, we removed the primary source of corticosterone by adrenalectomy. Close microglia-neuron interaction was reduced and increased again following corticosterone injection.

Our findings identify a sex-specific microglia-mediated mechanism of neuronal plasticity during anesthesia recovery, driven by corticosterone, thereby enhancing our understanding of sex differences in brain function."

Ketamine increases neuroplasticity in female mice but not in males "The surprising finding could help scientists develop better treatments for depression"

Corticosterone-linked microglial activity underpins sexually dimorphic neuroplasticity after ketamine anesthesia (open access)

Distribution of microglia (green) across the different cortical layers (orange) in the mouse visual cortex

Fig. 1. Female microglia interact with neurons, promoting spinogenesis and plasticity upon ketamine recovery.

Upending Decades of Debate, Scientists Discover Most Neurons are Jacks-of-All-Trades

Amazing stuff! This may also explain or support the enormous plasticity of the brain e.g. after brain injury etc.

Given the many and very varied topics on my blog, I must have tons of jack-of-all-trades neurons in my brain or are these curiosity neurons! Just kidding! 😊

"... The new research focuses on a mystery as old as neuroscience. Is each neuron in the brain a specialist devoted to a limited task, like a hammer or a saw, or do they tend to be generalists, jacks-of-all-trades like Swiss Army Knives? ...

that specialist neurons certainly do exist, but the majority appear to be generalists. ...

These new findings shed light on how the brain may ultimately prove capable of performing complex tasks. ...

Previous research found the brain is organized into modules devoted to vision and smell and other processes; so perhaps such specialization might extend all the way down to the level of neurons. On the other hand, the brain is an incredibly powerful general-purpose computer that can respond in an extraordinary number of ways to a huge variety of situations, so maybe its neurons are similarly generalist in nature. ...

To help resolve the debate, in the new study, the researchers developed a strategy where they looked only at mice, across many brain areas at once as the rodents all performed the same type of activity. This involved analyzing datasets much larger than typically studied, recordings of lots of neurons from the International Brain Laboratory consortium of activity in 43 regions across the mouse cortex on the level of single neurons. 

In primary sensory areas, such as the brain region devoted to vision, neurons behaved in specialized ways. However, elsewhere, neurons generated far more diverse responses. In other words, when it comes to the question of whether neurons are typically specialists or generalists, these new findings suggest the latter holds true. ..."

From the abstract:

"A long-standing debate in neuroscience concerns whether individual neurons are organized into functionally distinct populations that encode information differently (categorical representations and the implications for neural computation.

Here we systematically analysed how cortical neurons encode cognitive, sensory and movement variables across 43 cortical regions during a complex task (14,000+ units from the International Brain Laboratory public Brainwide Map dataset) and studied how these properties change across the sensory–cognitive cortical hierarchy.

We found that the structure of the neural code was scale dependent.

At the whole-cortex scale, neural selectivity was categorical and organized across regions in a way that reflected their anatomical connectivity.

However, within individual regions, categorical representations were rare and limited to primary sensory areas, and neuronal responses were instead very diverse.

With theoretical arguments and empirical evidence, we demonstrate that the diversity of neural responses enables high-dimensional representations and therefore high separability, allowing linear readouts to separate experimental conditions in many arbitrary ways.

Indeed, when accounting for information that is actually encoded in each area, all cortical regions exhibit maximal separability.

Our results indicate that cortical circuits prioritize diversity over categorical structure, supporting a computational regime geared towards high-dimensional, highly separable neural representations."

Upending Decades of Debate, Scientists Discover Most Neurons are Jacks-of-All-Trades | Columbia | Zuckerman Institute "Findings that neurons in mice are mostly generalists, instead of specialized for specific functions, has scientific community abuzz"

Rarely categorical, highly separable representations along the cortical hierarchy (open access)

Fig. 1: Conceptual framework and data structure.

Fig. 2: Large-scale functional organization of the cortex.

Fig. 4: A unified measure of response profile diversity.

Extended Data Fig. 7: A globally organized brain, with functional clustering closely reflecting anatomical structure.

A New Type of Neuroplasticity Rewires the Brain After a Single Experience

Recommendable!

"... Recently, neuroscientists described a new form of neuroplasticity that might be helping the brain learn across a timescale of several seconds — long enough to capture the behavioral process of learning from a single experience. In two recent reviews ... describe “behavioral timescale synaptic plasticity,” or BTSP. This type of learning in the hippocampus, the brain’s memory hub, is caused by an electrical change that affects multiple neurons at once and unfolds across several seconds. Researchers suspect that it may help the brain learn in a single attempt. ..."

From the abstract (1):

"Understanding how brains learn and remember remains among the most important challenges in science. Recent studies in the hippocampus implicate a new form of synaptic plasticity, named behavioral timescale synaptic plasticity (BTSP), in the generation of experience-based learning and memory. BTSP is a strong, bidirectional type of plasticity that affects synaptic weights over many seconds of time.

It is induced by single dendritic plateau potentials, as opposed to many action potentials, and is thus capable of producing new place cells in one trial.

Plateau potential initiation is controlled, at least in part, by local feedback inhibition and an instructive input from a higher-order brain region that potentially links the plasticity to current experience.

The new credit assignment procedure in BTSP provides a nonstandard mechanism for memory storage and retrieval that could mitigate the need for widespread synapse stabilization. In addition, it may allow hippocampal networks both to form memories of specific behavioral episodes and to generalize on the basis of past episodes.

Finally, recent BTSP investigations could provide a basis for future explorations into how brains learn and remember, ranging from the systems and cognitive levels down to the basic biochemical building blocks of learning and memory."

From the abstract (2):

"Hebbian synaptic plasticity is currently the main framework to relate neuronal activity, network structure, and learning and memory.

However, recent experimental and computational modeling studies have revealed a new form of synaptic plasticity termed behavioral timescale synaptic plasticity (BTSP).

It is triggered by dendritic plateau potentials associated with somatic burst firing, causes large changes in synaptic strength in a single shot, and operates on the timescale of seconds.

Here we review the recent advances in our understanding of the circuit, cellular, and molecular mechanisms of BTSP, its prevalence in the brain, its role in shaping neuronal representations, and the emerging ideas regarding its contribution to different forms of learning."

A New Type of Neuroplasticity Rewires the Brain After a Single Experience | Quanta Magazine "“Neurons that fire together, wire together” is not the full story. A novel mechanism explains how the brain can learn across longer timescales."

Behavioral timescale synaptic plasticity: properties, elements and functions (1, review article, no public access)

Behavioral Timescale Synaptic Plasticity: A Burst in the Field of Learning and Memory (2, no public access)

Dendrites, the extended branches that receive signals from other neurons, are the star players in a recently described type of neuroplasticity. In this image of stained pyramidal neurons from the cerebral cortex, rootlike dendrites extend from the cell bodies.

Astrocytes stabilize circuits in the adult mouse brain using the protein CCN1, which could be targeted to restore plasticity in injury, disorder, or disease

Good news! Amazing stuff! Could be a breakthrough!

"... This flexibility is called neuroplasticity, and our ability to learn, make new memories, and recover from injury all depend on it. ... team have now discovered a molecule that is critical for stabilizing brain circuits in adulthood: a protein called CCN1 secreted by star-shaped cells called astrocytes. The CCN1 pathway could now be a prime target for new therapeutics designed to support learning and plasticity in conditions like Alzheimer’s disease, depression, or PTSD, or to promote neural repair after injury or stroke."

From the abstract:

"Neural circuits in many brain regions are refined by experience. Sensory circuits support higher plasticity at younger ages during critical periods—times of circuit refinement and maturation—and limit plasticity in adulthood for circuit stability. How astrocytes, a glial subtype, maintain these differing plasticity levels, and whether they stabilize the properties of sensory circuits in adulthood, remain largely unclear.

Here we take a comprehensive approach to address these questions and establish astrocytes as key orchestrators of circuit stability.

Combining a transcriptomic approach with ex vivo electrophysiology and in vivo imaging, we identify that astrocytes release CCN1 to maintain synapse and circuit stability in the adult visual cortex.
Overexpressing CCN1 in astrocytes during the critical period promotes the maturation of inhibitory neurons, limits ocular dominance plasticity and promotes oligodendrocyte differentiation and maturation.

Conversely, knocking out astrocyte CCN1 in adults destabilizes binocular circuits and reduces myelination.

This establishes CCN1 as an astrocyte-secreted factor that stabilizes neuronal circuits by coordinating the maturation state of multiple cell types, and demonstrates that the composition and properties of sensory circuits require ongoing maintenance in adulthood, and that these maintenance cues are provided by astrocytes."

🧠 SALK DECEMBER NEWS 🧠

How do brains stay stable, and when might a dose of flexibility be helpful?

Astrocyte CCN1 stabilizes neural circuits in the adult brain (open access)

Fig. 1: Identifying CCN1 as an astrocyte pro-stability factor in the mouse visual cortex.

Transcranial random noise stimulation (tRNS) boosts math skills in adults

Good news! What else can be boosted?

I wish I had that treatment when I was in high school! I think, I suffered from the Matthew effect! 😊

"A shocking method for boosting math skills

Why do some kids seem to effortlessly pick up math skills, while others struggle no matter how hard they try? A growing body of research suggests that differences in neurobiology—the way a person’s brain is wired—may play a bigger role than external factors like socioeconomic status.

To explore this idea, scientists recruited 72 university students aged 18-30 to take part in a five-day math training program. Two-thirds of participants received a treatment known as transcranial random noise stimulation (tRNS), which delivers painless, non-invasive electrical currents to different parts of the brain; the rest were given a placebo.

Some students, scans revealed, started out with comparatively weak connections between the prefrontal and parietal regions of the brain. While these individuals initially had a harder time calculating solutions to math problems than peers with stronger natural connectivity, those who received tRNS over the dorsolateral prefrontal cortex—an area critical for learning and memory, focus, and problem-solving—showed significant improvements. ..."

"A painless, non-invasive brain stimulation technique can significantly improve how young adults learn maths, my colleagues and I found in a recent study. In a paper in PLOS Biology, we describe how this might be most helpful for those who are likely to struggle with mathematical learning because of how their brain areas involved in this skill communicate with each other. ...

Education often widens rather than closes the gap between high and low achievers, a phenomenon known as the Matthew effect. Those who start with an advantage, such as being able to read more words when starting school, tend to pull further ahead. Stronger educational achievement has been also associated with socioeconomic status, higher motivation and greater engagement with material learned during a class. ..."

From the abstract:

"Effortful learning and practice are integral to academic attainment in areas like reading, language, and mathematics, shaping future career prospects, socioeconomic status, and health outcomes. However, academic learning outcomes often exhibit disparities, with initial cognitive advantages leading to further advantages (the Matthew effect). One of the areas in which learners frequently exhibit difficulties is mathematical learning.

Neurobiological research has underscored the involvement of the dorsolateral prefrontal cortex (dlPFC), the posterior parietal cortex (PPC), and the hippocampus in mathematical learning. However, their causal contributions remain unclear. Moreover, recent findings have highlighted the potential role of excitation/inhibition (E/I) balance in neuroplasticity and learning.

To deepen our understanding of the mechanisms driving mathematical learning, we employed a novel approach integrating double-blind excitatory neurostimulation—high-frequency transcranial random noise stimulation (tRNS)—and examined its effect at the behavioral, functional, and neurochemical levels.

During a 5-day mathematical learning paradigm (n = 72) active tRNS was applied over the dlPFC or the PPC, and we compared the effects versus sham tRNS. Individuals exhibiting stronger positive baseline frontoparietal connectivity demonstrated greater improvement in calculation learning. Subsequently, utilizing tRNS to modulate frontoparietal connectivity,

we found that participants with weaker positive baseline frontoparietal connectivity, typically associated with poorer learning performance, experienced enhanced learning outcomes following dlPFC-tRNS only.

Further analyses revealed that dlPFC-tRNS improved learning outcomes for participants who showed reductions in dlPFC GABA when it was accompanied by a reduced positive frontoparietal connectivity, but this effect was reversed for participants who showed increased positive frontoparietal connectivity.

Our multimodal approach elucidates the causal role of the dlPFC and frontoparietal network in a critical academic learning skill, shedding light on the interplay between functional connectivity and GABAergic modulation in the efficacy of brain-based interventions to augment learning outcomes, particularly benefiting individuals who would learn less optimally based on their neurobiological profile."

ScienceAdviser

Could electric brain stimulation lead to better maths skills? (written by one of the authors of the study)

Functional connectivity and GABAergic signaling modulate the enhancement effect of neurostimulation on mathematical learning (open access)

LSD analogue synthesised by swapping just two atoms less likely to cause hallucinations and it exhibited strong neuroplastic effects

Good news! Amazing stuff! Flipping just two atoms!

"An analogue of the psychedelic drug LSD has been found to offer the same therapeutic effects as LSD but is less likely to cause the hallucinogenic trips associated with the drug. The researchers say that their work highlights the potential of rationally designed, non-hallucinogenic psychedelic analogues in the treatment of neuropsychiatric diseases such as schizophrenia, where the use of psychedelics is not recommended. ...

Using tests, such as the mouse head twitch response assay, which, ... correlates well with human hallucinogenic potency, they found that JRT did not produce hallucinogenic-like behaviours in mice dosed with LSD. ... in contrast to LSD, JRT does not bind the 5-HT2A receptor for very long. ..."

"... researchers have developed a new, neuroplasticity-promoting drug closely related to LSD that harnesses the psychedelic’s therapeutic power with reduced hallucinogenic potential. ..."

To design the drug, dubbed JRT, researchers flipped the position of just two atoms in LSD’s molecular structure. The chemical flip reduced JRT’s hallucinogenic potential while maintaining its neurotherapeutic properties, including its ability to spur neuronal growth and repair damaged neuronal connections that are often observed in the brains of those with neuropsychiatric and neurodegenerative diseases. ...

JRT exhibited powerful neuroplastic effects and improved measures in mice relevant to the negative and cognitive symptoms of schizophrenia, without exacerbating behaviors and gene expression associated with psychosis. ..."

From the significance and abstract:

"Significance

Psychedelic compounds, such as lysergic acid diethylamide (LSD), can promote the growth of atrophied cortical neurons, which is relevant to the treatment of numerous brain conditions.

However, their hallucinogenic properties have limited their adoption as medicines and preclude their use in certain patient populations, such as those with schizophrenia or a family history of psychosis.

By transposing only two atoms, we have created JRT, an exceptionally potent analogue of LSD with lower hallucinogenic potential, improved pharmacological selectivity, and the ability to produce a wide range of therapeutic effects.

Our work highlights the potential of rationally designed, nonhallucinogenic analogues of psychedelics for treating diseases where the use of psychedelics is contraindicated.

Abstract

Decreased dendritic spine density in the cortex is a key pathological feature of neuropsychiatric diseases including depression, addiction, and schizophrenia (SCZ).

Psychedelics possess a remarkable ability to promote cortical neuron growth and increase spine density; however, these compounds are contraindicated for patients with SCZ or a family history of psychosis.

Here, we report the molecular design and de novo total synthesis of (+)-JRT, a structural analogue of lysergic acid diethylamide (LSD) with lower hallucinogenic potential and potent neuroplasticity-promoting properties.

In addition to promoting spinogenesis in the cortex, (+)-JRT produces therapeutic effects in behavioral assays relevant to depression and cognition without exacerbating behavioral and gene expression signatures relevant to psychosis.

This work underscores the potential of nonhallucinogenic psychoplastogens for treating diseases where the use of psychedelics presents significant safety concerns."

LSD analogue synthesised by swapping just two atoms less likely to cause hallucinations | Research | Chemistry World

Researchers Develop an LSD Analogue with Potential for Treating Schizophrenia (original news release)

Molecular design of a therapeutic LSD analogue with reduced hallucinogenic potential (open access)

JRT differs from LSD in the positioning of two atoms. An N and C in the ergoline structure of LSD have been swapped to make the less hallucinogenic JRT

Fig. 2 Total synthesis of JRT.

Substantial u-shaped remodeling of the brain in a pregnant woman

Amazing stuff!

"During pregnancy, the brain undergoes substantial remodeling. However, longitudinal characterization of these changes is lacking. Servin-Barthet et al. analyzed magnetic resonance imaging scans before, during, and after pregnancy in 127 women undergoing their first pregnancy.

Gray matter volume decreased rapidly during pregnancy and partially recovered (albeit slowly and only partially) postpartum. Volume changes were correlated with alterations in estrogens and were particularly evident in high-order cognitive networks. At the behavioral level, stronger gray matter volume recovery was associated with reduced hostility toward the newborn. Understanding brain adaptation during pregnancy could be leveraged to promote well-being during the postpartum period."

From the abstract:

"Growing evidence places the gestational period as a unique moment of heightened neuroplasticity in adult life.

In this longitudinal study spanning pre, during, and post pregnancy, we unveil a U-shaped trajectory in gray matter (GM) volume, which dips in late pregnancy and partially recovers during postpartum.

These changes are most prominent in brain regions associated with the Default Mode and Frontoparietal Network.

The U-shaped trajectory is predominantly linked to gestational factors, as it only presents in gestational mothers and correlates with fluctuations in estrogens over time.

Finally, the mother’s mental health status mediates the relationship between postpartum GM volume recovery and maternal attachment at 6 months postpartum. This research sheds light on the complex interplay between hormones, brain development, and behavior during the transition to motherhood. It addresses a significant knowledge gap in the neuroscience of human pregnancy and opens new possibilities for interventions aimed at enhancing maternal health and well-being."

In Other Journals | Science

Pregnancy entails a U-shaped trajectory in human brain structure linked to hormones and maternal attachment (open access)

Fig. 1: Longitudinal cortical gray matter volume trajectory across pregnancy and postpartum (N = 179).

How psychedelic compounds stimulate neuronal growth

Are we finally beginning to better understand the processes of addiction, depression and the like!

"Psychedelics belong to a group of compounds called psychoplastogens, which can promote neuronal growth and restore atrophied connections in the brain. This ability makes the molecules promising as potential treatments for neuropsychiatric diseases such as chronic depression and addiction. In a new study, scientists have untangled the mechanism of how these compounds trigger the rewiring of the brain, providing a better understanding of why these compounds differ from other neurochemicals that share the same binding targets ...

Classic psychedelics such as psilocybin and LSD bind to the 5-hydroxytryptamine 2A (5-HT2A) receptor, an important G-protein-coupled receptor (GPCR) that’s involved in cellular signaling. But so does serotonin, the ubiquitous, mood-dictating neurotransmitter. The lingering mystery is why serotonin doesn’t stimulate the same neuroplasticity effects that psychedelic compounds do.

The new study has found the answer. “The location of the 5-HT2A receptor is critical for determining the kinds of signaling pathways that a ligand can induce,” ...

For a GPCR, the 5-HT2A receptor is weird. Most GPCR proteins reside on the cellular surface to relay signals between the cell and its environment. But in neurons, the majority of 5-HT2A receptors populate the inside of the cell. ... team discovered that psychoplastogens need to reach the receptors within neurons to spark intracellular signaling. Merely hitting the receptors on the outside won’t count.

“The fact that psychedelics may interact with intracellular receptors—that’s really interesting,” ... “a major advance.”

Serotonin—unlike N,N-dimethyltryptamine (DMT),which is found in ayahuasca brew, for example—is a polar molecule, so it can’t easily cross the lipid bilayer of the cell membrane to get inside. On the other hand, greasy compounds can access the intracellular space ...

However, if serotonin is able to enter the cell, it too can kick-start the same signaling events that would lead to neuronal growth. After [team] forced neurons to take up serotonin, the researchers observed them sprouting more branches and more protrusions as a result. The researchers also genetically engineered mice to express a serotonin transporter and saw antidepressant-like behavior, unlike control mice that did not produce the same protein.

The paper is a landmark study, because it opens up new questions about this particular plasticity mechanism, ... “What are the pathways activated by the serotonin 2A receptor located intracellularly? What are the pathways responsible for these medical effects?” ..."

"The mechanism underlying psychedelic action

Psychedelic compounds promote cortical structural and functional neuroplasticity through the activation of serotonin 2A receptors. However, the mechanisms by which receptor activation leads to changes in neuronal growth are still poorly defined. Vargas et al. found that activation of intracellular serotonin 2A receptors is responsible for the plasticity-promoting and antidepressant-like properties of psychedelic compounds, but serotonin may not be the natural ligand for those intracellular receptors ..."

From the absract:

"Decreased dendritic spine density in the cortex is a hallmark of several neuropsychiatric diseases, and the ability to promote cortical neuron growth has been hypothesized to underlie the rapid and sustained therapeutic effects of psychedelics. Activation of 5-hydroxytryptamine (serotonin) 2A receptors (5-HT2ARs) is essential for psychedelic-induced cortical plasticity, but it is currently unclear why some 5-HT2AR agonists promote neuroplasticity, whereas others do not. We used molecular and genetic tools to demonstrate that intracellular 5-HT2ARs mediate the plasticity-promoting properties of psychedelics; these results explain why serotonin does not engage similar plasticity mechanisms. This work emphasizes the role of location bias in 5-HT2AR signaling, identifies intracellular 5-HT2ARs as a therapeutic target, and raises the intriguing possibility that serotonin might not be the endogenous ligand for intracellular 5-HT2ARs in the cortex."

How psychedelic compounds stimulate neuronal growth

Psychedelics promote neuroplasticity through the activation of intracellular 5-HT2A receptors (no public access)

5-HT2A receptors (colored) usually reside inside neurons, unlike most other signalling proteins that usually sit on the cell surface.

Tuning into brainwave rhythms speeds up learning in adults

Amazing stuff! Can I get a learning boost soon?

"Scientists have shown for the first time that briefly tuning into a person’s individual brainwave cycle before they perform a learning task dramatically boosts the speed at which cognitive skills improve.

Calibrating rates of information delivery to match the natural tempo of our brains increases our capacity to absorb and adapt to new information, according to the team behind the study. ...

Alpha waves oscillate between eight to twelve hertz: a full cycle every 85-125 milliseconds. However, every person has their own peak alpha frequency within that range.

Scientists used these readings to create an optical “pulse”: a white square flickering on a dark background at the same tempo as each person’s individual alpha wave.

Participants got a 1.5-second dose of personalised pulse to set their brain working at its natural rhythm – a technique called “entrainment” – before being presented with a tricky quick-fire cognitive task: trying to identify specific shapes within a barrage of visual clutter. ...
The learning rate for those locked into the right rhythm was at least three times faster than for all the other groups. When participants returned the next day to complete another round of tasks, those who learned much faster under entrainment had maintained their higher performance level. ..."

From the abstract:

"... Here, we test whether this variability in learning ability relates to individual brain oscillatory states. We use a visual flicker paradigm to entrain individuals at their own brain rhythm (i.e. peak alpha frequency) as measured by resting-state electroencephalography (EEG). We demonstrate that this individual frequency-matched brain entrainment results in faster learning in a visual identification task (i.e. detecting targets embedded in background clutter) compared to entrainment that does not match an individual’s alpha frequency. Further, we show that learning is specific to the phase relationship between the entraining flicker and the visual target stimulus. EEG during entrainment showed that individualized alpha entrainment boosts alpha power, induces phase alignment in the pre-stimulus period, and results in shorter latency of early visual evoked potentials, suggesting that brain entrainment facilitates early visual processing to support improved perceptual decisions. These findings suggest that individualized brain entrainment may boost perceptual learning by altering gain control mechanisms in the visual cortex, indicating a key role for individual neural oscillatory states in learning and brain plasticity."

Tuning into brainwave rhythms speeds up learning in adults The first study to show that delivering information at the natural tempo of our neural pulses accelerates our ability to learn.

Learning at your brain’s rhythm: individualized entrainment boosts learning for perceptual decisions (open access)

Fig. 1: Experimental design and stimuli.

Fatherhood changes men’s brains, according to before-and-after MRI scans

Amazing stuff! The significant physiological and neurological changes going on in a first time mother have been reported and studied for a long time (the article also contains a description).

The article almost compulsively or desperately tries to associate these changes in first time fathers with extended paternity leave offered in other countries and with LGBTQ. Quite annoying this political spin! The article is actually authored by an associate professor and a PhD student (the two authors were also the researchers involved in the study).

"... The time fathers devote to child care every week has tripled over the past 50 years in the United States. The increase in fathers’ involvement in child rearing is even steeper in countries that have expanded paid paternity leave or created incentives for fathers to take leave ...
there is surprisingly little research about how fatherhood affects men. Even fewer studies focus on the brain and biological changes that might support fathering. ...

In terms of brain function, for instance, gay male fathers who are primary caregivers show stronger connections between parenting brain regions when viewing their infants, compared with secondary male caregivers. ...
We found several significant changes in the brains of fathers from prenatal to postpartum that did not emerge within the childless men we followed across the same time period. In both the Spanish and Californian samples, fathers’ brain changes appeared in regions of the cortex that contribute to visual processing, attention and empathy toward the baby. ..."

From the abstract:

"Emerging evidence points to the transition to parenthood as a critical window for adult neural plasticity. Studying fathers offers a unique opportunity to explore how parenting experience can shape the human brain when pregnancy is not directly experienced. Yet very few studies have examined the neuroanatomic adaptations of men transitioning into fatherhood. The present study reports on an international collaboration between two laboratories, one in Spain and the other in California (United States), that have prospectively collected structural neuroimaging data in 20 expectant fathers before and after the birth of their first child. The Spanish sample also included a control group of 17 childless men. We tested whether the transition into fatherhood entailed anatomical changes in brain cortical volume, thickness, and area, and subcortical volumes. We found overlapping trends of cortical volume reductions within the default mode network and visual networks and preservation of subcortical structures across both samples of first-time fathers, which persisted after controlling for fathers’ and children’s age at the postnatal scan. This study provides convergent evidence for cortical structural changes in fathers, supporting the possibility that the transition to fatherhood may represent a meaningful window of experience-induced structural neuroplasticity in males."

Fatherhood changes men’s brains, according to before-and-after MRI scans Neuroscientists know that pregnant mothers’ brains change in ways that appear to help with caring for a baby. Now researchers have identified changes in new fathers’ brains, too.

First-time fathers show longitudinal gray matter cortical volume reductions: evidence from two international samples (no public access)

I am not endorsing following book:

How pregnancy dramatically resculpts the brain

Recommendable, but this video has a few ideological overtones! Amazing stuff!

Tinkering with Gut Microbes Boosts Brain Plasticity in Mice

Recommendable!

"... Now, a study published January 11 in Cell Reports finds that the environment could act indirectly: living in enriched environments changes the animals’ gut microbiota, which appears to modulate plasticity. ...
To assess plasticity, the team used monocular deprivation, where the input to one eye is blocked by sewing it shut so that neurons in the visual cortex are driven to shift to responding to the other eye. In mice raised in enriched cages, this shift can be observed after several days of deprivation, while the neurons of mice raised in standard housing never make the shift. 
In a first step, the researchers analyzed the spectrum of bacteria present in the guts of mice raised in standard cages and in enriched cages. Although both groups of mice ate the same diet, the microbiota composition in their gut began to differ as the mice grew up, and had diverged substantially by 90 days after birth. "

From the abstract:

"Exposing animals to an enriched environment (EE) has dramatic effects on brain structure, function, and plasticity. ... revealing that gut microbiota signals are crucial for EE-driven plasticity. Developmental analysis reveals striking differences in intestinal bacteria composition between EE and standard rearing (ST) mice, as well as enhanced levels of short-chain fatty acids (SCFA) in EE mice. Depleting the microbiota of EE mice with antibiotics strongly decreases SCFA and prevents activation of adult ocular dominance plasticity, spine dynamics, and microglia rearrangement. SCFA treatment in ST mice mimics EE induction of ocular dominance plasticity and microglial remodeling. Remarkably, transferring the microbiota of EE mice to ST recipients activates adult ocular dominance plasticity. Thus, experience-dependent changes in gut microbiota regulate brain plasticity."

Here is A Prayer For Animals Used In Experimentation

Tinkering with Gut Microbes Boosts Brain Plasticity in Mice | The Scientist Magazine® Intestinal bacteria contribute to the effect of stimulating environments on the brain’s ability to adapt, a study concludes.

The gut microbiota of environmentally enriched mice regulates visual cortical plasticity (open access)

Scientists Discover "Gorditas" and Other Novel Brain Cell Types

Amazing stuff! One would wish billionaires like Jeff Bezos, Richard Branson, and Elon Musk would invest more money in brain research instead of space race trips! There is still so much to discover regarding our brains!

"... The results suggest new roles for glial cells, best known for providing support to neurons, and could prompt a better understanding of how brains remain plastic into adulthood, when the vast majority of neurons no longer undergo cell division.... Most mammalian brain cells, be they neurons or glia, are generated during embryonic development, and reservoirs of stem cells become largely, if not entirely, dormant in adulthood. The small trickle of activity that is left can help the brain respond to change, sometimes by generating new neurons to help with learning or by producing cells in response to injury or disease.
One pool exists in the brains of adult humans and mice, in an area called the ventricular-subventricular zone (V-SVZ). The walls of the two lateral ventricles, cavities filled with cerebrospinal fluid, are lined with stem cells, and along these walls, the cells have a regional identity—where a stem cell lies on the wall dictates what it differentiates into ..."

"Quiescent [dormant] neural stem cells (NSCs) in the adult mouse ventricular-subventricular zone (V-SVZ) undergo activation to generate neurons and some glia. Here we show that platelet-derived growth factor receptor beta (PDGFRβ) is expressed by adult V-SVZ NSCs that generate olfactory bulb interneurons and glia. Selective deletion of PDGFRβ in adult V-SVZ NSCs leads to their release from quiescence, uncovering gliogenic domains for different glial cell types. These domains are also recruited upon injury. We identify an intraventricular oligodendrocyte progenitor derived from NSCs inside the brain ventricles that contacts supraependymal axons."

Scientists Discover "Gorditas" and Other Novel Brain Cell Types | The Scientist Magazine® A pool of neural stem cells that ordinarily lies dormant in the brains of adult mice spawns two types of never-before-documented glial cells when artificially reactivated, potentially pointing to a novel mechanism of brain plasticity.

Release of stem cells from quiescence reveals gliogenic domains in the adult mouse brain (no public access)