Research articles

Korin et al. use CyTOF mass cytometry to characterize immune cell populations in the naive mouse brain (parenchyma, choroid plexus and meninges). This single-cell analysis of cell-surface proteins reveals the presence and phenotype of distinctive immune populations in the mouse brain compartment.

The mechanisms underpinning neuronal death in Alzheimer's disease (AD) remain unclear. Caccamo and colleagues show that necroptosis contributes to neurodegeneration in AD. Blocking necroptosis reduced neuronal loss in a mouse model of AD, suggesting that necroptosis might be a therapeutic target in AD.

Yates and colleagues statistically dissect MT and LIP responses during motion discrimination. They show decreasing temporal weighting of motion in MT, consistent with psychophysical weighting, and show that LIP spikes encode the upcoming choice more than integrated motion or simultaneously recorded MT spikes, suggesting an indirect relationship between these areas.

An expanded repetition of a DNA sequence within the C9orf72 gene is the most common genetic cause for motor neuron disease and frontotemporal dementia. In this study, the authors show that this expansion causes increased genomic breaks and reduces the cell's ability to repair the breaks, ultimately leading to neuronal cell death.

Recent evidence supports a functional connection between gut microbiota and the nervous system. Here the authors show that gut microbiota plays a critical role in the development of chemotherapy-induced pain. This role of the microbiota is likely mediated, in part, by Tlr4 expressed on hematopoietic cells, including macrophages.

Survey of postzygotic mosaic mutations (PZMs) in 5,947 trios with autism spectrum disorders (ASD) discovers differences in mutational properties between germline mutations and PZMs. Spatiotemporal analyses of the PZMs also revealed the association of the amygdala with ASD and implicated risk genes, including recurrent potential gain-of-function mutations in SMARCA4.

The mechanistic basis of how novel stimuli become familiar with repeated exposures has remained elusive. Molas et al. demonstrate that familiarity activates the interpeduncular nucleus, thereby reducing motivation to explore. Familiarity signaling in the interpeduncular nucleus is bidirectionally modulated by habenula and ventral tegmental area afferents to control novelty preference.

The authors show that transcranial magnetic disruption of the right temporoparietal junction decreases strategic behavior during competitive interactions. The altered behavior relates to neural activity changes both locally and in interconnected prefrontal areas. These brain networks may causally underlie the ability to predict the behavior of other agents.

A fundamental goal of learning is to establish neural patterns that cause desired behaviors. This paper demonstrates that sleep-dependent processing is required for credit assignment and the establishment of task-related activity reflecting the causal neuron-behavior relationship. Decoupling of spiking to sleep slow oscillations using optogenetics methods disrupted this process.

Microglia are the macrophages of the CNS, with innate neuroimmune function, and play important roles in tissue homeostasis, CNS development and neurodegeneration. Here human microglial gene expression profiles were generated. Human and mouse microglia were highly similar, except for aging-regulated genes, indicating that microglial aging differs between humans and mice.

Corticospinal cells of the motor cortex act as a direct link between the cortex and movement-generating circuits within the spinal cord. The authors demonstrate that the relationship between activity of these cells and movement changes with time and learning, indicating a flexible cortical output to drive movements.

The authors report two new engineered AAV capsids that efficiently deliver genes throughout the adult central and peripheral nervous systems after intravenous administration. Complementing these capsids is an AAV toolbox that enables cell morphology and genetic manipulation studies of defined neural cell types in transgenic or wild-type animals.

Using in vivo calcium imaging in a mouse model of neuropathic pain, the authors found a persistent increase in the activity of somatosensory cortex pyramidal neurons following peripheral nerve injury. Repeated pharmacogenetic activation of somatostatin-expressing inhibitory neurons after injury not only corrected this abnormal cortical activity but also prevented the development of chronic pain.

Strong genetic evidence points to a significant role for heterozygous mutations to general chromatin remodeling factors, such as CHD8, in autism. Gompers et al. combine genomic, neuroanatomical and behavioral approaches to present an initial integrative picture of transcriptional mechanisms and widespread impacts of Chd8 haploinsufficiency across brain development in mice.

Using large-scale analysis of protein interactions and bioinformatics, Li et al. describe the organization of the core-scaffold machinery of the postsynaptic density and its assembly in protein-interaction networks. The authors show how mutations associated with complex brain disorders are distributed along spatiotemporal protein complexes and modulate their protein interactions.

The authors identified a protective genetic allele associated with lower PU.1 (SPI1) expression in myeloid cells by conducting a genome-wide scan of Alzheimer's disease (AD). PU.1 binds the promoters of AD-associated genes (e.g., CD33, MS4A4A & MS4A6A, TYROBP) and modulates their expression, suggesting it may reduce AD risk by regulating myeloid cell gene expression.

The authors demonstrate that optical fibers with tapered tips can homogenously illuminate either elongated brain structures or dynamically selected subregions. Tapered fibers achieve efficient optogenetic stimulation in vivo with minimal tissue damage. In addition, a single fiber can deliver light of multiple wavelengths to independently controlled regions.

This study characterizes the properties of disease-causing mutations that produce sporadic amino acid replacements in proteins of people with autism and developmental delay. The mutations tend to cluster and reoccur at specific regions important to protein function, highlighting for future follow-up ∼200 candidate genes, many involved in neuronal signaling.

Combining electrophysiology and computational modeling, the authors show that the dendrites of entorhinal cortex stellate and pyramidal cells are electrically excitable and that this improves the robustness of grid cell firing. The results suggest that active dendrites are critical for spatial navigation, a fundamental computation in the brain.

The precise mechanisms that cause human obesity remain unknown. Here the authors illustrate how increased expression of Cadm1, a mediator of synapse assembly, is relevant to weight gain. Reduction of Cadm1 in multiple brain regions promoted weight loss, and these observations provide insight into the neuronal pathways contributing to obesity.