Research articles

In this study, the authors show that expression of Brn3a with Ngn1 or 2 can induce the direct reprogramming of mouse and human fibroblasts into peripheral sensory neurons. They further demonstrate that these neurons exhibit the expression profiles and physiological properties of mature sensory neurons and are responsive to nociceptor agonists.

Earlier work suggests that spatial phase preferences are randomly distributed throughout visual cortex. In this study, the authors present evidence towards a columnar organization for spatial phase that resembles organization for orientation preference, which suggests that this phase organization may contribute to the emergence of orientation maps.

Lecoq and colleagues introduce a two-photon microscope with two articulated arms that can image nearly any two brain regions, nearby or distant, simultaneously. They validate this new system by imaging calcium signals in two visual cortical areas in behaving mice, and find evidence suggesting activity fluctuations can propagate between cortical areas

The authors report an optical method involving simultaneous stimulation of single neurons using a red-shifted optogenetic probe and recording of population activity using a green fluorescent calcium sensor. They use this technique to manipulate individual place cells in CA1 during spatial navigation in a virtual reality environment.

The authors show that mice lacking Fragile X Mental Retardation Protein (FMRP) have disrupted neuronal migration during cortical development. FMRP-deficient mice also show altered excitatory-to-inhibitory balance early postnatally. They identify N-cadherin as a target of FMRP and show that re-expressing N-cadherin can rescue these phenotypes in FMRP-deficient mice.

The authors report that in mice, the cerebellum modulates the activity of the striatum via a disynaptic pathway to facilitate optimal motor control. Dysfunction of this pathway can contribute to dystonia.

Corticotropin-releasing factor (CRF) and dopamine (DA) are critical for stress and motivation, respectively. The authors show that CRF is synthesized in DA neurons and released in the ventral tegmental area, where it affects GABAergic inputs to DA neurons and mediates the motivational effects of nicotine withdrawal and escalation of nicotine intake.

Primate cortex can be organized with specialization and hierarchical principles, but presently there is little evidence for how it is organized temporally. Across six separate datasets, the authors find a hierarchical ordering of intrinsic fluctuation of spiking activity, with timescales that increase from sensory to prefrontal areas.

The counter-regulatory response (CRR) restores blood glucose levels after hypoglycemia. The authors identify a population of leptin receptor– and cholecystokinin-expressing neurons in the parabrachial nucleus of the hypothalamus that modulates the CRR. These neurons are activated by hypoglycemia, inhibited by leptin and project to the ventromedial hypothalamus.

Noonan syndrome (NS) is an autosomal dominant genetic disease that is co-morbid with cognitive deficits in a subset of patients. Using mouse models of NS, a study now shows that the synaptic plasticity and memory deficits in mouse models of NS are due primarily to the dysfunction in the MEK-Erk kinase pathways, and pharmacological intervention that alters MEK-Ras function can alleviate physiological and behavioral deficits in the mouse models of NS.

The many different behaviors mediated by the posterior parietal cortex (PPC) could arise from distinct specialized categories of neurons or from a single population of PPC neurons that is leveraged in different ways. The authors test this by studying rat PPC neurons during tasks involving multisensory decisions and conclude that a single network of neurons can support different behavioral demands.

This Resource article provides detailed expression data from the striatum and cerebral cortex of early prenatal human samples, ranging in age from 2 to 20 weeks post-conception. Using a number of different analyses, the authors describe the transcriptional, spatio-temporal expression and functional profile that distinguish human striatal from neocortical neurons while also elucidating some differences between human and mouse striatal development.

Fragile X Syndrome (FXS) patients and the mouse model of the disease are known to have increased neocortical network excitability and hypersensitivity to sensory stimuli. The current study describes dendritic ion channel dysfunction to underlie sensory hypersensitivity in the FXS mouse model, particularly due to the reduction and dysfunction of dendritic h- and BK_Ca channels. The study also shows pharmacological rescue of cortical hyperexcitability using BK_Ca channel openers.

Training macaque monkeys with distinct sets of shapes resulted in novel domain formation in inferotemporal cortex. The localization of these domains was similar across monkeys, regardless of set-training order. The stereotyped location of the training-induced domains suggests a pre-existing architecture, and the authors explored various possible proto-architectures.

Neuregulin 1 (NRG1) type III is a key mediator of Schwann cell development and myelination and is known to undergo proteolytic cleavage to produce an intracellular fragment. In this study, the authors show that this intracellular fragment of NRG1 modulates myelination by inducing the expression of a prostaglandin synthase (L-PGDS) which, in turn, leads to prostaglandin production and activation of GPR44.

Previous work has suggested that the scaffolding protein ankyrin G is essential for the clustering of Na⁺ channels at the nodes of Ranvier. However, in this study, the authors show that, in the absence of ankyrin G, the complex of ankyrin R and βI spectrin can mediate Na⁺ channel clustering at the nodes.

In this paper, Atasoy and colleagues use a genetically-encoded synaptic marker for electron microscopy (GESEM) to probe long-range neuronal connectivity at the nanoscale level. The authors fused the horseradish peroxidase to the vesicle-associated membrane protein 2 (VAMP2) to label synaptic vesicles. Focusing on the mouse feeding system, they show that this new tool is suitable for connectomics analyses of genetically defined populations of neurons.

In this study, the authors show that the scaffolding proteins ankyrin B and ankyrin G are expressed by Schwann cells and oligodendrocytes, respectively, and are enriched on the glial membrane at paranodal junctions where they interact with neurofascin 155. In addition, they find that ankyrins in oligodendrocytes have key roles in rapid and efficient paranode formation in the CNS.

The authors selectively modify chromatin in a specific gene in vivo to examine the link between chromatin dynamics and drug- and stress-evoked responses. They report that histone methylation or acetylation at the FosB locus in nucleus accumbens is sufficient to control drug- and stress-evoked transcriptional and behavioral responses.

Fine-scale synchrony of neural activity determines the nature of neural coding, but its underlying mechanisms are unclear. Here the authors find that coincident electrical and chemical synaptic inputs are nonlinearly integrated in overlapping retinal ganglion cell dendrites to produce synchronous spiking.