Articles in 2017

New studies provide compelling evidence that the number and length of myelin sheaths generated by oligodendrocytes in the CNS are controlled by local calcium levels, linking axonal activity to individual myelin sheath formation.

Super-resolution optical imaging of presynaptic terminals shows that a protein essential to all known forms of neurotransmitter release is clustered in small assemblies that likely correspond to release sites for synaptic vesicle fusion.

Both nucleus accumbens and orexin play clear roles in motivated behavior, but the functions of orexin projections to accumbens are poorly understood. Blomeley et al. show that this pathway, via specific orexin excitation of dopamine D2 receptor–expressing neurons, can inhibit reward seeking and exploratory drive when danger is perceived.

Neuroscience is not spared from wrestling with gender disparity issues. Progress toward more balanced representation has been slow, but improvement is possible with consistent and focused efforts.

The medial entorhinal cortex contains spatially selective grid cells, whose lattice-like firing patterns are proposed to support path-integration-based navigation. However, direct behavioral evidence has been lacking. Gil et al. disrupt grid cells in a targeted manner, establishing a clear link between grid cell codes and navigation.

The glial scar plays critical but divergent roles during regeneration of the mammalian CNS. Here the authors propose that in-depth analysis of the functionally heterogeneous populations of reactive glia within the scar is needed to fully understand the glial scar’s dual nature.

The authors investigate grid cell dynamics after removal of a border between two environments. Near the transition between environments, grid fields changed location, resulting in local spatial periodicity and continuity between the original maps.

Grid cell activity may subserve path integration, but a direct link is lacking. The authors selectively disrupt retro-hippocampal region grid cell activity and show that disrupted grid cell firing impairs performance in a path integration task.

Long-lasting synaptic plasticity is regarded as a mechanism for learning and memory. Using genetically engineered mice in which the C-terminal domains of AMPA receptor subtypes are switched, the authors reveal that GluA1 and GluA2 differentially regulate synaptic plasticity and contribute to different forms of learning.

The authors show that Munc13-1 molecules form multiple supramolecular self-assemblies that serve as vesicular release sites. Having multiple Munc13-1 assemblies affords a stable synaptic weight, which confers robustness of synaptic computation.

The authors live-image zebrafish myelin sheath Ca²⁺ activity in vivo and find that high-amplitude long-duration Ca²⁺ transients precede calpain-dependent sheath retractions while frequent low-amplitude short-duration transients drive sheath growth.

Synaptotagmin-1 (Syt1) controls synaptic vesicle–membrane attachment activities via its C2B domain. These correlate with release synchronization and synaptic short-term facilitation, revealing a mechanism for Syt1-mediated synchronous release.

Myelin formed by oligodendrocytes enables rapid, energy-efficient information transmission in CNS, but its development is unclear. The authors show that the rate of intracellular calcium transients regulates elongation of developing myelin sheaths.

The mosquito-borne ZIKA virus triggers microcephaly in human newborns. The authors report that the microcephaly results from induction of endoplasmic stress that interferes with generation and survival of projection neurons in the cerebral cortex.

A genome-wide association study of delay discounting (DD) on 23,127 subjects found that genotype accounted for 12% of variance in DD; the DD genetic signature overlapped with ADHD, schizophrenia, depression, smoking, personality, cognition and weight.

Using single-cell RNA-sequencing, the authors record snapshots of the dynamic sensory-experience-dependent transcriptome across all cell types of the visual cortex in mice exposed to a light stimulus. The authors note diverse cell-type-specific programs in pyramidal neuron subtypes and robust non-neuronal responses that may regulate experience-dependent neurovascular coupling and myelination.

The authors present a new computational approach to automatically annotate, analyze, visualize and easily share whole-brain datasets at cellular resolution, based on a scale-invariant and interactive mouse brain reference atlas. The authors applied this framework to define the organization and cocaine-induced activity of corticostriatal circuits.