News & Views 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.

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.

To decide how much we would like to eat a food item, our brain automatically decomposes it into constituent nutrients. The quantities of the different nutrients are represented in distinct parts of the lateral orbitofrontal cortex and then integrated by the medial orbitofrontal cortex to provide a global value judgment.

A leaky blood–brain barrier may contribute to neuropsychiatric disease. Chronic stress is shown to alter blood–brain barrier permeability, allowing an inflammatory response to penetrate the brain. The deficit is mostly around the nucleus accumbens, an area central to motivation. The affected animals exhibit features of depression.

Sommeijer et al. describe a previously unrecognized role of the thalamus: development of inhibition in the thalamus regulates ocular dominance plasticity, a form of critical-period plasticity regulation previously ascribed solely to the cortex.

Mouse models have generally failed to recapitulate the dopaminergic neurodegeneration seen in Parkinson's disease. Expressing mutant α-synuclein in a background of elevated dopamine generates mice with nigrostriatal degeneration.

The discovery of a circuit from the midcingulate cortex to the posterior insula that is essential for cortical sensitization sheds light on the plasticity mechanisms responsible for the transition from acute to chronic pain.

Physiological and optogenetic dissection of discrete locus coeruleus neuronal populations reveals a functional disassociation, with heterogeneous engagement of locus coeruleus neurons in either fear learning or extinction models.

Central amygdala directs behavioral responses to emotionally salient stimuli. While most studies have focused on aversive responses, some central amygdala neurons promote feeding and are positively reinforcing.

Upon injury of the developing mouse cerebellum, endogenous repair mechanisms can heal the brain and prevent behavioral motor deficits. At the right time, with the right cues, the brain can repair itself.

Inputs to the central complex, the navigation center of Drosophila, are strongly modulated by the visual stimulus history. These history effects carry forward to bias turning behavior when flies choose between two visual stimuli.

What is the basis for the feeling that someplace or someone is familiar? Molas et al. have identified brain structures involved in signaling familiarity, a necessary element for the expression of preference for novelty.

A study introduces innovative ways to test whether neural population activity exhibits structure above and beyond that of its basic components.

Zika virus infection is associated with birth defects, including microcephaly, but also with disorders of peripheral nerves. Oh et al. use rodent and human cell models to explore how the virus affects the peripheral nervous system.

Hexanucleotide repeat expansions in C9orf72 gene locus create double jeopardy, first by leading to DNA–RNA R-loops that spawn double-strand breaks and second by the synthesis of dipeptide repeats that hinder DNA repair. This two-pronged mechanism may explain neurodegeneration in amyotrophic lateral sclerosis and frontotemporal dementia.

A Cre-dependent capsid selection method, CREATE, was used to produce adeno-associated viral vectors that allow gene delivery to the entire central and peripheral nervous systems, with multicolor labeling of single cells.

A combination of computational modeling, neuroimaging and a causal manipulation of brain activity in humans reveals how the brain represents beliefs about how our choices will affect those of others we interact with.

Effectiveness of EGFR treatment is impaired through an early adaptive response. TNF–JNK–Axl–ERK signaling contributes to this primary resistance to EGFR inhibition and might serve as novel target to improve EGFR inhibition.