Reviews & Analysis

Moscarello and Penzo propose that mutually inhibitory circuits within the central nucleus of the amygdala implement a ‘winner-takes-all’ mechanism that guides transitions across defensive modes defined by threat-imminence theory.

Studying the natural wanderings of the living brain is extremely challenging. Bolt et al. describe a new framework for considering the brain’s intrinsic activity based on the geophysical concepts of standing and traveling waves.

The language network in the brain shows similar properties across 45 languages spanning 12 language ‘families’. The language areas are lateralized to the left hemisphere, selective for language, and strongly functionally inter-connected. Variability among speakers of different languages is similar to the variability that has been reported among English speakers.

This Review provides a comprehensive overview of presynaptic applications of optogenetic tools, including the associated challenges, current limitations and future directions for this approach.

A new study shows that infra-slow cortical norepinephrine oscillations shape the micro-structure of sleep and transitions to micro-arousals, wakefulness or rapid eye movement (REM) sleep. Prolonged descending phases of these oscillations promote the occurrence of spindle-rich intermediate sleep, which is involved in memory consolidation.

During cortical development, the generation of neurons from progenitors coincides with increasing vascularization and oxygen levels in the fetal brain and the transition from anaerobic to aerobic metabolism. Dong et al. identify lactate, a metabolite of anaerobic glycolysis, as a multifunctional regulator that coordinates synchrony of cortical neurogenesis and angiogenesis.

A new cell state of disease-associated oligodendrocytes (DOLs) has been identified, which presents a transcriptional program that is probably driven by neuroinflammation and is shared among different non-immune glial cells across multiple pathologies of the central nervous system.

Epilepsy is the most common childhood neurological disease, and nearly 20% of affected children develop drug-resistant childhood epilepsy (DRCE). Using single-cell analysis methods, Kumar et al. have identified pro-inflammatory interactions between microglia and T cells in brain tissue from individuals with DRCE. This work may help to identify therapeutic targets for DRCE.

We report light-gated channels in a fungus-like protist that are highly selective for K⁺ over Na⁺. These microbial rhodopsin channels, named kalium channelrhodopsins, enable robust inhibition of mouse cortical neurons with millisecond precision. In addition, kalium channelrhodopsins reveal a previously unknown potassium selectivity mechanism.

The solutions found by neural networks to solve a task are often inscrutable. We have little insight into why a particular structure emerges in a network. By reverse engineering neural networks from dynamical principles, Dubreuil, Valente et al. show how neural population structure enables computational flexibility.

How and where negative affect is represented in the brain is a central neuroscientific question. A new study identifies neural correlates of both general negative affect and those specific to stimulus type by conducting multimodal functional MRI experiments.

Sleep disruption is a common but poorly understood feature of neurodevelopmental disorders including autism spectrum disorder. A study by Bian et al. reveals that sleep disruption in adolescent mice leads to long-lasting changes in social novelty preferences. Importantly, these perturbations can be restored through balanced actions in midbrain dopamine systems.

The extent to which neurogenesis occurs in adult primates is still controversial. Single-cell RNA sequencing, immunofluorescence staining, and ex vivo neurosphere culture experiments were performed using the adult macaque hippocampus. The results reveal robust adult neurogenesis in the dentate gyrus of the primate hippocampus.

Myelin, iron, and calcium are major constituents of brain tissue with magnetic properties that can be detected non-invasively using MRI. Using quantitative susceptibility mapping, we estimated the magnetic susceptibility of brain structures in 35,273 participants, creating a new resource to identify novel, non-invasive markers of brain health.

A new ‘meta-matching’ algorithm developed by He et al., published in this issue of Nature Neuroscience, enables small MRI datasets to piggyback on larger datasets to boost prediction accuracy. This innovation may aid in efforts toward personalized psychiatry.

Eating disorders are prevalent and, in far too many cases, fatal. This review covers advances in genetics, neuroimaging, and animal models, and encourages a more unified science of eating disorders.

Dopamine (DA) neurons in the ventral tegmental area bidirectionally regulate the activity of serotonin neurons in the dorsal raphe nucleus. Low-strength activity causes inhibition via dopamine receptor D2, whereas high- strength activity causes activation via dopamine receptor D1, and this circuit contributes to anorexia nervosa-like behaviors in mice.

Degeneration of dopaminergic neurons in the substantia nigra is a pathological hallmark of Parkinson’s disease (PD). However, not all dopamine-producing neurons degenerate. Kamath, Abdulraouf et al. find that there are ten transcriptionally defined dopaminergic subpopulations in the human substantia nigra, but only one carries significant PD genetic risk and is vulnerable to neurodegeneration in PD.

Activity-regulated myelination adaptively tunes neural circuit function in health. In rodent models of generalized epilepsy, recurrent seizures aberrantly increase myelination specifically within the seizure circuit. Blocking this seizure-induced myelination abrogates the progressive increase in seizure burden and ictal hypersynchrony that occurs in mice with intact activity-regulated myelination, indicating that maladaptive myelination can contribute to disease progression in epilepsy.

Two recent papers reveal that the brain can regulate its own immune responses by sending molecular cues to immune cells in the skull bone marrow via the cerebrospinal fluid. Furthermore, experimental spinal cord injury or bacterial meningitis specifically activate local vertebral and skull-resident hematopoietic cell injury responses.