Volume 24 Issue 2, February 2021

Fibrotic scarring after inflammation is well-characterized in peripheral tissues, but its role in the CNS is less clear. A new study shows that local proliferation of CNS fibroblasts drives fibrotic scar formation in response to circulating inflammatory cell infiltration in a model of multiple sclerosis, which may limit repair.

Recent research has discovered new connections between cerebellar neurons, revealed abundant inputs related to reward, demonstrated a cellular solution for the temporal credit assignment problem and restructured theories of cerebellar learning.

The authors demonstrate the presence of SARS-CoV-2 in the nasopharynx and brain, suggesting that the virus is present in the CNS and may enter through the olfactory mucosa, exploiting the close vicinity of olfactory mucosal, endothelial and nervous tissue.

Rodin and Dou et al. characterized genome-wide somatic mutation in autistic and control brains, revealing that even unaffected individuals may possess dozens of brain somatic mutations and providing insight into the role of somatic mutation in autism.

Zhu et al. discover that in human brain there is widespread anatomic distribution of low-frequency somatic, mosaic L1 insertions, using deep whole-genome sequencing of neuronal and glial fractions and machine-learning analysis.

Sherman et al. describe the contribution of mosaic copy number variants (mCNVs) to the risk of autism spectrum disorder (ASD). Probands with ASD carry a significant burden of mCNVs relative to their unaffected siblings.

This paper shows that maternal immune activation in mice induces changes in the mRNA translation machinery in the fetal brain and activates the integrated stress response in male fetuses, which mediates neurobehavioral abnormalities.

Overexpression of complement C4A is associated with schizophrenia risk. Using a novel mouse model, Yilmaz et al. find that increased expression of C4A leads to abnormal synaptic pruning and behavior, suggesting its importance as a therapeutic target.

Neurons are generated throughout life in the mammalian hippocampus. Bottes et al. used intravital imaging and comparative single-cell transcriptomics to identify long-term self-renewing neural stem cells in the adult mouse hippocampus.

Dorrier et al. identified fibrotic scarring in a mouse model of multiple sclerosis that arises from the proliferation of fibroblasts in the meninges and surrounding blood vessels, and determine that reducing scarring decreases motor symptom severity.

This study shows how different myeloid cell types contribute to damage and repair following cerebrovascular injury, a pathology common to many central nervous system disorders, and offers new therapeutic opportunities to improve clinical outcomes.

Two-photon photostimulation and imaging of a cortical short-term memory circuit reveal intercalated modules that can independently maintain memory. The modules are defined by connectivity between neurons with similar task-related tuning.

Poulter et al. report on vector trace cells (VTCs) in the hippocampal subiculum. VTCs support vector coding for previously encountered, now absent, objects and boundaries, potentially facilitating navigation to remembered goals.

Leng et al. uncover the molecular signature of neuronal subpopulations that are selectively vulnerable to tau aggregation and death early in Alzheimer’s disease in the human entorhinal cortex and other brain regions, validating RORB as a marker.