Research articles

Using a combination of optogenetics, single-cell molecular profiling and paired electrophysiological recordings in the mouse visual cortex, Pfeffer and colleagues derived the connectivity matrix of three major classes of interneurons with their post-synaptic GABAergic targets. This study provides a comprehensive overview of the wiring rules of the inhibition of inhibition in the cortex.

In this study, the authors show that information regarding both the identity and the value of a given odor is multiplexed in the anterior piriform cortex. Specifically, they find that value is encoded by changes in firing rate while identity is determined by sniff-locked spiking.

To investigate how visual input is combined with information about the current task, the authors recorded neural responses in inferotemporal (IT) and perirhinal (PRH) cortex as macaque monkeys performed a match to sample task. Although both areas represented similar amounts of information, extracting the behaviorally relevant information was easier in PRH.

The authors show that reconsolidation of alcohol-related memories activates mammalian target of rapamycin complex 1 (mTORC1) in select amygdalar and cortical regions and systemic or central amygdalar inhibition of mTORC1 during reconsolidation disrupts alcohol-associated memories, leading to a long-lasting suppression of relapse, suggesting a potential therapeutic target to prevent relapse.

This technical report describes a method to clear fixed brain tissues while allowing for fluorescent dye tracing and retaining cellular morphology. The authors demonstrate the utility of the technique by obtaining a wiring diagram for sister mitral cells.

Existing data are consistent with a role for the orbitofrontal cortex (OFC) either in regulating emotion and enhancing behavioral flexibility or in updating valuations on the basis of motivational states. Here the authors show that excitotoxic lesions of OFC impair value updating but do not alter either behavioral flexibility or emotion regulation and that previous observations may have been the result of damage to nearby fiber tracts.

Zhao and colleagues find that neuropathic pain is accompanied by an increase in the expression of an antisense long noncoding RNA (lncRNA) that downregulates Kcna2 currents and increases excitability in rat dorsal root ganglion neurons. Preventing the expression of the so-called Kcna2 antisense RNA mitigates neuropathic pain symptoms.

Here the authors show that measures of pupil diameter, which are thought to track levels of LC-NE activity and neural gain, are correlated with the degree to which learning is focused on stimulus dimensions that individual human participants are more predisposed to process. They further show that the pupillary and behavioral variables are correlated with global changes in the strength and clustering of functional connectivity, as brain-wide fluctuations of gain would predict.

In this study, the authors show that MeCP2 interacts with the NCoR/SMRT co-repressor complex and that a discrete cluster of Rett syndrome–causing mutations in the C-terminal domain of MeCP2 disrupts this interaction, impairing transcriptional repression. Knock-in mice expressing one of these MeCP2 missense mutations exhibit severe motor phenotypes.

Using a combination of computational modeling and electrophysiological recordings, the authors show that the dynamics of spike-frequency adaptation have the effect of temporally decorrelating incoming signals. This decorrelation makes for more energy-efficient information transfer in the CNS.

In this paper, Korb and colleagues find that Arc can shuttle in and out of the nucleus in an activity-dependent manner. The authors further demonstrate that the nuclear translocation of Arc participates in homeostatic plasticity by promoting the formation of PML nuclear bodies, which in turn decreases GluA1 transcription, eventually contributing to the downscaling of synaptic strength.

The authors use high-throughput histology to construct three-dimensional maps of the vascular architecture throughout mouse vibrissal cortex. Modeling of the vascular networks revealed that microvessels are highly interconnected; do not form functional 'modules', as previously suggested; and lead to flow patterns that explain the origin of single vessel strokes.

The authors show that the TNFα receptor, expressed on peripheral target tissue, can act as a ligand to induce reverse TNFα signaling in superior cervical ganglion neurons, promoting neurite growth and branching. This reverse signaling is crucial in establishing sympathetic innervation.

The authors use two-photon calcium imaging, EEG and electrophysiology to study ensemble neuronal activity in genetically altered mice that lack the Fmr1 protein: a model of Fragile X syndrome. Unanesthetized Fmr1^−/− mice showed high synchrony of neocortical network activity and higher firing rates during sleep.

The authors use mouse behavior, electrophysiology and optogenetics to dissect the temporal interactions between whisker movement, neural activity and sensation of touch. Their results suggest that mice integrate coding of touch with movement over timescales of a whisking bout to produce perception of active touch.

The authors show that mating-induced partner preference in monogamous prairie voles is associated with increased histone acetylation at the oxytocin and vasopressin V1a receptor promoters, and subsequent upregulation of these genes. Histone deacetylase inhibitors induced partner preference in females even in the absence of mating.

Ependymal cell cilia regulate cerebrospinal fluid flow through the cerebral ventricles. Here the authors show that the metabolic peptide melanin-concentrating hormone (MCH) increases cilia beat frequency in the third ventricle, and a lack of the MCH receptor increases ventricle size.

Exome sequencing of 47 ALS trios (patients and their unaffected parents) identified de novo mutations, including a mutation in the neuronal chromatin remodeling complex component, SS18L1. SS18L1 interacted with the ALS protein FUS, and mutation of SS18L1 in primary neurons resulted in impaired neurite outgrowth.

The calyx of Held synapse in the auditory brainstem is an unusually large and fast synapse. Using genome-wide screening and conditional deletion in mice, Xiao and colleagues identify BMP signaling as a crucial factor in the development of the functional and structural properties of this large central synapse.

Here the authors describe a recurrent neural network model that tells time on the order of seconds and generates complex spatiotemporal motor patterns in the presence of high levels of noise. Robustness is achieved through the tuning of the recurrent connections, which produces stable patterns in the face of perturbations.