Research articles

In this study, the authors show that subjecting adult animals to prolonged social isolation results in impaired heterochromatin formation in oligodendrocytes and decreased myelin thickness, specifically in the prefrontal cortex. This suggests that social experience can regulate myelin plasticity in the adult via an epigenetic program.

Brain-machine interfaces (BMIs) have typically focused on performing single-targeted movements. Here the authors report the presence of two subpopulations of neurons in the monkey premotor cortex that allow two planned targets to be simultaneously held in working memory without degradation. They use this finding to develop a BMI that concurrently decodes a full motor sequence in advance of movement and then accurately executes it.

The function of neuroligins in regulating synapse formation remains controversial. Here, the authors show that neuroligin-1 (NL1) regulates activity-dependent synaptogenesis and mature synapse number on cortical layer 2/3 pyramidal neurons in vivo. They find that relative differences in transcellular expression of NL1, rather than absolute expression levels, regulate synapse number.

Newly generated dentate granule cells in the hippocampus at 4 weeks after their 'birth' are more plastic than existing neurons. The authors use a combined retroviral and optogenetic approach to show that silencing these 4-week-old cells, but not cells of other ages, impaired retrieval of hippocampal memory.

The EphB family of receptor tyrosine kinases can signal bidirectionally and functions in a kinase-dependent and kinase-independent manner. To determine the importance of the kinase activity of EphBs for axonal guidance and synaptogenesis, the authors used a chemical genetic method and generated knock-in mice that allow the kinase activity of EphBs to be inhibited without altering kinase-independent functions of EphBs. They find that specific inhibition of EphB kinase activity had no effect on synaptogenesis, but impaired axonal guidance, thereby implicating the kinase function of EphB in one neuronal process, but not other processes that are nevertheless dependent on EphBs.

In worms, male exploratory behavior is influenced by two competing needs, food and sex. In this paper, the authors highlight the importance of the pigment dispersing factor signaling pathway in the normal function of a gender-shared neuronal circuit that is involved male-specific reproductive drive.

In this study, the authors used two-photon imaging in macaque monkey to show that orientation and spatial frequency maps are intimately related at a fine spatial scale. They find that the map gradients have a striking tendency toward orthogonality and co-vary negatively from cell to cell at the spatial scale of cortical columns.

The authors assessed the contributions of early life stress (ELS) and childhood cortisol levels to adolescent resting-state functional connectivity. In females, ELS predicted increased cortisol levels in childhood, which predicted decreased amygdala-ventromedial prefrontal cortex (vmPFC) functional connectivity. Amygdala-vmPFC connectivity was inversely correlated with anxious sympotms and positively correlated with depressive symptoms.

The authors use a computational approach (NETBAG+) to integrate and analyze diverse genetic data and apply this to study schizophrenia-associated genetic variations. They identify gene networks related to axon guidance, synaptic function, cell mobility and chromosomal remodeling.

Ubiquitin proteasome system–mediated, neuronal activity–dependent protein turnover at synapses often occurs in an ensemble fashion where a group or groups of postsynaptic density (PSD) proteins are degraded together in a homeostatic response. This study shows that the synaptic level of the PSD scaffolding protein called GKAP (also known as SAPAP1) is bidirectionally regulated in a homeostatic fashion and is mediated by differential phosphorylation by CaM kinase II isoforms.

In this study, the authors report that a focal cortical injury can induce changes in the excitability of thalamocortical neurons that contributes to the maintenance of cortical seizures. In addition, silencing these neurons via a closed-loop optogenetic approach is sufficient to interrupt these seizures.

In this study, the authors show that Hox5 genes are essential for the organization, survival and axonal branching of motor neurons required for breathing. Unexpectedly, this requirement for Hox5 activity persists to later developmental stages.

Butko and colleagues report the invention of fluorescent and photo-oxidizing versions of a molecular probe named TimeSTAMP that allows temporal tagging of newly synthesized proteins of interest. The study uses these new tools to track basal and pharmacologically-induced synthesis of the synaptic protein PDS-95 in real time via live fluorescent imaging and/or with ultrastructural resolution using electron microscopy.

This study uses EEG in humans to isolate and track an evolving, domain-general decision signal, which varies with accumulated evidence, but is independent of overt actions.

Neural progenitor cells (NPCs) are known to be influenced by their local environment. However, in the current study, the authors show that NPCs can also secrete signaling proteins that regulate microglial cell function.

The authors explore how sensory maps are reshaped by experience in vivo, using chronic two-photon calcium imaging to follow whisker-evoked activity of individual layer 2/3 neurons in adult mouse barrel cortex over weeks. By first measuring activity with whiskers intact and then with continued trimming of all but one whisker, they describe how the redistribution of population activity underlies large-scale cortical remapping.

Different types of bipolar cells in the retina carry distinct visual signals to select types of amacrine cells and ganglion cells. The authors show that a single bipolar cell can evoke distinct responses in different ganglion cells and that this signal divergence is the result of interactions with amacrine cells.

Dopamine signaling is known to influence sleep and arousal in Drosophila. Here the authors identify the circuitry underlying the effect of dopamine on arousal, which involves D1 dopamine receptors in the dorsal fan-shaped body as the target of dopaminergic projections.

Using a knock-in strategy to ablate a Cdk5-targeted serine phosphorylation site on residue 478 of the TrkB receptor, the authors demonstrate the role of this phosphorylation in activity-dependent functional and structural plasticity, as well as in learning and memory. They further show that TIAM1 and Rac1 act downstream of TrkB S478 phosphorylation during spine remodeling.

GPR88 is an orphan G protein–coupled receptor expressed in striatal medium spiny neurons (MSNs). The authors show that deletion of Gpr88 in mice leads to hyperactivity, poor motor coordination and impaired cue-based learning. MSNs lacking GPR88 show increased excitation and reduced inhibition in vitro, and enhanced firing rates in vivo.