Neuroscience

eLife assessment

Signaling mediated by Semaphorins and their receptors Nrp1 and Nrp2 is crucial for regulating the morphology of dendritic spines and dendritic arborization during development. In this manuscript, the authors found that the post-translational modification of S-palmitoylation dictates the subcellular localization and trafficking of Nrp2, but not Nrp1, and is required for Sema3F-dependent pruning of spines on the apical dendrites of layer V cortical neurons. The study provides important insights into how semaphorin signaling achieves spatial specificity on diverse downstream cellular events.

eLife assessment

The authors state that there is scant experimental evidence of divisive normalization of neural responses in the human brain. They used fMRI BOLD response to high-level stimuli to explore normalization in V1, object-selective (LO and pFs) and category-selective regions (EBA and PPA) as well effects of attention on cortical responses. Specifically, the authors first test the degree to which BOLD responses to body parts and houses exhibit responses predicted by a non-linear normalization model, compared to two linear models (weighted sum and weighted average). They find that responses, when considering responses to one vs two stimuli, are best fit with the normalization model. They then suggest that object-based attention effects can be better accounted for by a normalization model of attention, compared to attention variants of the aforementioned models. The paper could potentially be an important contribution to the fields of perceptual and cognitive neuroscience, but the conclusions are not sufficiently supported by the data at this stage. Several theoretical and methodological concerns limit the conclusions of this study.

eLife assessment

This manuscript makes a valuable contribution to the field. The authors have developed a compelling network model to study mechanisms for the emergence of oscillations in the beta range in the primary motor cortex during movement preparation, and their propagation as traveling waves across the cortical sheet. The model is able to recapitulate several features of motor cortical activity acquired experimentally. Due to the recent results suggesting a functional role for traveling waves, it is of great interest to discover the mechanisms underlying such phenomena, and this work is an interesting step in that direction. However, the evidence for the reported new insights is incomplete at this stage, due to some weaknesses that remain to be addressed.

eLife assessment

This paper will be of fundamental interest to many sub-disciplines of neuroscience, ranging from cognitive neuroscientists to cellular neuroscience. It provides compelling and substantial brain and behavioral evidence of a novel intervention that can boost long-term memory. The key claims of the manuscript are generally well supported by the data, though the correlational nature of the data in different types of experiments raises some issues about interpretation.

eLife assessment

This manuscript will be of interest to a wide range of cell biologists interested in understanding cell-cell communication. The discovery that an engulfing cell can control the extrusion and degradation of large vehicles from its target cell is important and intriguing. The authors present compelling data that show that exophers (large neuronal extrusions proposed to discard toxic cargo) are taken up by adjacent hypodermal cells, split into smaller fragments, and eventually degraded by lysosome fusion. The authors identify a number of small GTPases and accessory components, as well as the phagocytic receptor (CED-1) and the likely eat-me signal (phosphatidylserine).

eLife assessment

This study provides fundamental insights into the relationship between single neuron activity in superficial layers of the cortex and electrical signals recorded at the cortical surface. Based on solid measurements, the results indicate a weak correlation between individual layer 2/3 neuron activity and multiunit activity recorded at the surface, whose interpretation could be reinforced. In particular, a strong contribution of layer 1 axons to surface signals is suggested but relies on incomplete evidence.

eLife assessment

This manuscript tests an important assumption about how sensory information is processed and used to guide motor choices. The widely held assumption is that sensory-motor circuits are capable of integrating evidence, but the validity and generality of this 'principle' have been recently questioned by studies suggesting that other computational operations may lead to similar psychophysical results, mimicking integration without actually performing it. This study makes a compelling case that the integration assumption was likely correct all along and that the model mimicry can be easily disambiguated by using appropriate sensory stimuli and task designs that permit rigorous analyses.

eLife assessment

This important study provides convincing evidence that locus coeruleus is activated during visuomotor mismatches. Gain of function optogenetic experiments complement this evidence and indicate that locus coeruleus could be involved in the learning process that enables visuomotor predictions. This study, therefore, sets the groundwork for the circuit dissection of predictive signals in the visual cortex. Loss-of-function experiments would strengthen the evidence of the involvement of locus coeruleus in prediction learning. These results will be of interest to systems neuroscientists.

eLife assessment

This paper will be of considerable interest to researchers studying the psychological and neural basis of variation in prosocial behavior. The authors use a sophisticated combination of computational modeling and EEG to show that variation in generosity produced by changes in context (i.e., disadvantageous vs. advantageous inequality) and variation due to individual differences in concern for others both seem to occur early, during the perceptual or valuation stage of a choice, rather than later on during choice comparison. However, these two sources of variation also appear to operate through distinct mechanisms during this stage of processing, which spurs further questions about the drivers of human prosocial behavior.

eLife assessment

The authors examine the function of Tomosyn, in dense core vesicle fusion in neuronal cultures from mice expressing conditional alleles of tomosyn and tomosyn-2. The authors show here that while loss of tomosyns did not affect dense core vesicle exocytosis, it reduced the expression of several key dense core cargos, including BDNF. However, "rescue" experiments are needed to validate the specificity of the effects.