Articles in 2017

The nature of astrocyte diversity in the adult brain has remained poorly defined. The authors identify five astrocyte subpopulations in the brain that exhibit extensive molecular and functional diversity. They uncover correlative populations in malignant glioma, providing insight into how diverse astrocyte populations contribute to synaptogenesis, tumor pathophysiology and neurological disease.

The hypothalamic arcuate–median eminence (Arc-ME) complex is rich with functionally distinct cell types, a fraction of which have been characterized. The authors profile 20,921 individual cells by single-cell RNA-seq, identifying 50 Arc-ME cell types and their markers, determining each's response to energy status and implicating two neuron populations in the genetic control of obesity.

Su et al. investigated the chromatin accessibility status of neurons in the adult mouse dentate gyrus at different timepoints after activation at the genome-wide level. Their study provides a potential mechanism by which neuronal activity may reshape the epigenetic landscape, thereby dynamically changing transcriptome and neuronal properties over time.

The identity of the cell types contributing to the [¹⁸F]FDG positron emission tomography signal remain highly controversial. In this study, the authors demonstrate that activating glutamate astrocytic transport increases brain [¹⁸F]FDG uptake. These findings indicate that astrocytes may also impact [¹⁸F]FDG positron emission tomography signal.

Social behaviors require neural circuits to process social cues and orchestrate motivational states. This study identifies a subpopulation of hypothalamic neurons expressing neurotensin that are engaged by social and hormonal signals. These neurons project to midbrain dopaminergic reward systems to promote and reinforce social and motivated behavior in a hormone-sensitive manner.

Dysfunction of the neuroendocrine HPA axis is associated with a variety of physiological and psychological pathologies. The authors show that corticotropin-releasing factor type 1 receptors within the hypothalamic paraventricular nucleus are a key central component of HPA axis regulation that prepares the organism for chronic exposure to stressful stimuli.

The role of pericytes in the regulation of cerebral blood flow (CBF) and neurovascular coupling remains unclear. Using loss-of-function pericyte-deficient mice, the authors report that pericyte degeneration reduces CBF responses to neuronal stimuli and oxygen supply to the brain, leading to metabolic stress, neuronal dysfunction and neurodegeneration.

Using magnetic resonance spectroscopy, Shibata et al. show that continuous training conducted after performance improvement has been maximized hyperstabilizes the skill learned and protects it from subsequent new learning by drastically changing early visual areas from excitatory (glutamate)-dominant to inhibitory (GABA)-dominant neurochemical environments.

Pregnancy results in changes to maternal physiology and brain that may extend into older age. New results show that pregnancy-induced reductions in gray matter volume remain 2 years after childbirth in humans.

The biological drive to consume salt ensures that we consume adequate sodium for survival. In this issue of Nature Neuroscience, two articles provide insight into the neurons and circuits that regulate sodium appetite.

Many spatial correlates have been identified that form the neural basis for navigation. Two studies have now uncovered a new cell type: bidirectional cells, which fire when the head is pointing in one of two opposing directions.

Representations in excitatory neurons generally narrow as they are refined. Odor representations in interneurons, however, broaden with maturation and learning, as connections between interneurons and projection neurons expand.

Using large-network calcium imaging in alert mouse frontal cortex, the authors identify a significant covariance of responses of VIP interneurons and pyramidal cells. Optogenetic interrogation of this brain region revealed a pull–push inhibitory circuit driven by neuromodulation of VIP interneurons that contrasts with canonical feedforward push–pull excitation.

Effective social behavior requires comprehension of social cues and use of those cues to guide behavior. This study uncovers an amygdala circuit that is necessary for socially driven valuation of environmental cues. The strength of this circuit correlates with social learning, and augmentation of this circuit enhances abnormal social learning.

Inputs to midbrain dopamine neurons control rewarding and drug-related behaviors. The authors found that nucleus accumbens inputs and local GABA neurons inhibit dopamine neurons through distinct populations of GABA receptors. Furthermore, genetic deletion of GABA_B receptors from dopamine neurons selectively increased behavioral sensitivity to cocaine.

The authors investigate the role of inhibition in shaping spatial selectivity of CA1 place cells. Combining whole-cell recordings, optogenetics and computational modeling, they demonstrate that inhibition enhances both rate and temporal coding of space by counteracting noise from broad out-of-field excitation.

We present a special set of Review articles on neuroimmune communication that highlight how the immune system and nervous system are anatomically connected, mechanistically communicate and reciprocally influence the other's function.

Historically, the CNS has been considered immunologically privileged and separated from the peripheral immune system. In this Review, the authors highlight recent advances in our understanding of how the CNS interacts with peripheral immune cells in the context of health and disease.

Neural pathways regulate immune responses and inflammation. Recent research using technological advances in molecular genetics has provided important insights into the functional anatomy and cellular and molecular mechanisms of this regulation. These advances resulted in clinical trials exploring neuromodulation in the treatment of inflammatory and autoimmune disorders.

The function of rapid eye movement (REM) sleep remains unclear. By examining how REM sleep affects synapses in the mouse cortex, the authors show that REM sleep is fundamental to brain development, learning and memory consolidation by selectively pruning and maintaining newly formed synapses via dendritic calcium spike-dependent mechanisms.