Neuroscience

eLife Assessment

This important study identifies species- and sex-specific neuronal cell types and gene expression in the preoptic area (POA) to help understand the evolutionary divergence of social behaviors. The evidence from single-nucleus RNA sequencing and immunostaining is compelling and suggests that cellular differences in the POA may contribute to behavioral variations such as mating and parental care that are apparent in two closely related deer mouse species. These rich observations provide an entry point for future hypothesis-driven experiments to demonstrate a causal role for these populations in sex- or species-variable behaviors in vertebrates. These data will be a resource that is of value to behavioral neuroscientists.

eLife Assessment

This is a valuable study, tackling the long-standing issue of the difficulty in imaging the inferior olive and addressing the most relevant questions with a rigorous approach. The technological advance allowed the authors to generate solid experimental evidence with high-quality data. The results are presented clearly and the analyses are rigorous.

eLife Assessment

This study investigates trial-by-trial inter-areal interactions in the visual cortex of the mouse and the monkey by analyzing two previously published datasets. The authors find that activity in one layer (in mice) or one area (in monkeys) can partially predict neural activity in another layer or area on the single-trial level in different experimental contexts. This valuable finding expands previously known contributions of stimulus-independent downstream activity to neural responses in the visual cortex by demonstrating how these change under varying visual stimuli as well as in the absence of visual stimulation. While the methodology is solid, the analysis for the monkey data is incomplete and would benefit from including a second animal.

eLife assessment

The study presents a useful computational analysis of how the ratio between excitatory and inhibitory neural numbers affects coding capacity. The authors show that increasing the proportion of inhibitory neurons (as observed in upper cortical layers compared to the input recipient layer 4) increases the dimensionality of neural activity and improves the encoding of time-varying stimuli. However, the evidence about the role of the inhibitory population in coding is incomplete because numerical results are neither supported by analytical mathematical results nor include controls for changes in firing thresholds or subtypes of inhibitory neurons.

eLife Assessment

This study presents useful findings on the differences between male and hermaphrodite C. elegans connectomes and how they may result in changes in locomotory behavioural outputs. However, the study appears incomplete with respect to the relationship between sex-specific AVA wiring and male mate-finding. Another area of concern is that the analysis does not consider animal-to-animal variability in the wiring when attempting to identify significant differences between the male and hermaphrodite.

eLife Assessment

This manuscript addresses a mechanism by which dopamine (DA) regulates synaptic plasticity. The authors build upon their previous finding that DA applied after a timing pattern that ordinarily induces long-term depression (LTD) now induces long-term potentiation (LTP). The new findings that this "DA-dependent LTP" involves de novo protein synthesis, a cyclicAMP signalling pathway, and calcium-permeable AMPA receptors (CP-AMPARs) are of valuable significance. The conclusions are convincing and largely supported by the evidence provided.

eLife Assessment

The paper presents a valuable theoretical treatment of the role of passage of time in optimal decision strategies in pursuit based tasks. The computational evidence and methodologies employed are novel, and the authors offer solid evidence for the majority of the claims.

eLife Assessment

Birdsong production depends on precise neural sequences in a vocal motor nucleus HVC. In this useful biophysical model, Daou and colleagues identify specific biophysical parameters that result in sparse neural sequences observed in vivo. While the model is presently incomplete because it is overfit to produce sequences and therefore not robust to real biological variation, the model has the potential to address some outstanding issues in HVC function.

eLife Assessment

This study presents a valuable theoretical exploration on the electrophysiological mechanisms of ionic currents via gap junctions in hippocampal CA1 pyramidal-cell models, and their potential contribution to local field potentials (LFPs) that is different from the contribution of chemical synapses. The biophysical argument regarding electric dipoles appears solid, but the evidence would be stronger if their predictions are tested against experiments. A shortage of model validation and strictly comparable parameters used in the comparisons between chemical vs. junctional inputs makes the modeling approach incomplete; once strengthened, the finding can be of broad interest to electrophysiologists, who often make recordings from regions of neurons interconnected with gap junctions.

eLife Assessment

This important study characterizes and validates a new activity marker - fast labelling of engram neurons (FLEN) - which is transiently active and driven by cFos, allowing the monitoring of intrinsic and synaptic properties of engram neurons shortly after the learning experience. The results convincingly demonstrate the utility of this novel viral tool for studying early changes in the properties of engram cells. However, the study would benefit from exploring how accurately FLEN reflects endogenous cFos activity, how this labelling technique compares to previous versions, and from careful consideration of alternative explanations such as changes in release probability.