Neuroscience

eLife Assessment

This valuable study combined whole-head magnetoencephalography (MEG) and subthalamic (STN) local field potential (LFP) recordings in patients with Parkinson's disease undergoing deep brain stimulation surgery. The paper provides convincing evidence that cortical and STN beta oscillations are sensitive to movement context.

eLife Assessment

This important study by Wong et al. addresses a longstanding question in the field of associative learning regarding how a motivationally relevant event can be inferred from prior learning based on neutral stimulus-stimulus associations. The research provides convincing behavioral and neurophysiological evidence to address this question. The manuscript will be interesting for researchers in behavioral and cognitive neuroscience.

eLife Assessment

This fundamental work demonstrates the importance of considering overlapping modes of functional organization (i.e. gradients) in the hippocampus, showing associations with aging, dopaminergic receptor distribution and episodic memory. The evidence supporting the conclusions is convincing, although not all analyses were performed in a replication sample. The work will be of broad interest to basic and clinical neuroscientists.

eLife Assessment

This important work combines molecular genetics and behavioral analyses to identify inhibitory neurons in the female medial preoptic area as a neural locus that is activated following male ejaculation and whose prolonged activity plays a key role in the regulation of female sexual motivation. These experiments are rigorous and well-performed. The data are compelling and demonstrate that a subpopulation of neurons in the medial preoptic area are selectively activated following the completion of mating in females. The medial preoptic area has long been implicated as critical to sexual behavior in both sexes; however the use of a self-paced mating assay for females provides fine control over manipulating and monitoring cellular activity in this region during more naturalistic behavior. In addition, this study may act to inspire others to further explore the additional brain regions found to show upregulation of neural activity (Fos) during mating completion in females using the datasets generated here.

eLife Assessment

This important study identifies a new key factor in orchestrating the process of glial wrapping of axons in Drosophila wandering larvae. The evidence supporting the claims of the authors is convincing and the EM studies are of outstanding quality. However, the quantification of the wrapping index, the role of Htl/Uif/Notch signaling in differentiation vs growth/wrapping, and the mechanism of how Uif "stabilizes" a specific membrane domain capable of interacting with specific axons might require further clarification or discussion. The work will be of interest to neuroscientists working on glial cell biology.

eLife Assessment

This manuscript provides convincing evidence derived from diverse state-of-the-art approaches to suggest that non-dopaminergic projection neurons in the ventral tegmental area (VTA) make local synapses. These important findings challenge the prevailing wisdom that VTA interneurons exclusively form local synaptic contacts and instead reveal that VTA neurons expressing interneuron markers also form long-range projections to forebrain targets such as the cortex, ventral pallidum, and nucleus accumbens. Given the importance of VTA interneurons to many models of VTA-linked behavioral functions, these findings have significant implications for our understanding of the neural circuits underlying reward, motivation, and addiction.

eLife Assessment

This important study investigates the signaling pathways regulating retinal regeneration. Convincing evidence shows that the sphingosine-1-phosphate (S1P) signaling pathway is inhibited following retinal injury. Small-molecule activators and inhibitors support a model in which S1P signaling must be inhibited to generate Müller glial progenitor cells-a key step in retinal regeneration. The presented results support the major conclusions. However, whether the drug treatments directly or indirectly affect the Müller cells remains unclear.

eLife Assessment

This study provides important observations about the role of Hebbian synapse rewiring (which predicts that correlated activity between neurons begets stronger synapses) on brain connectivity development, by examining a naturally emerging case where Hebbian predictions can be tested because neurons with differing activity undergo development under otherwise similar conditions (albino mouse lateral geniculate nucleus [LGN], where retinal ganglion cells [RGCs] from the contralateral retina form inappropriate projections alongside a majority of ipsilateral RGCs). The evidence supporting the conclusions is compelling, with combined confocal imaging and serial electron microscopy (EM) reconstructions showing complete synaptic isolation of aberrantly projecting RGCs onto LGN thalamocortical projection neurons, and mixed connectivity onto LGN local interneurons. The morphological descriptions of connectivity presented here will be of interest to researchers studying synaptic connectivity and plasticity during development.

eLife Assessment

This important paper provides an unbiased landscape for the cerebellar cortical outputs to the brainstem nuclei. By conducting anatomical and physiological analyses of the axonal terminals of Purkinje cells, the data provides convincing evidence that Purkinje cells innervate brainstem nuclei directly. The results show that in addition to previously known inputs to vestibular and parabrachial nuclei, Purkinje cells synapse onto the pontine central grey nucleus but have little effect on the locus coeruleus and mesencephalic trigeminal neurons.

eLife Assessment

This fundamental study comprehensively characterizes insulin producing cells (IPCs) resident in the Drosophila melanogaster brain. A compelling experimental tour de force, the combination of connectomics, mapping of receptors for neuromodulators, electrophysiological recordings, Calcium imaging and optogenetics demonstrates that IPCs operate as a functionally heterogeneous population, as necessary to address continuously changing metabolic demands. These findings will be of interest to both neuroscientists and physiologists seeking to study context-dependent neuroendocrine regulation.