Neuroscience

eLife assessment

This paper posits that higher uncertainty environments should lead to more reliance on episodic memory, finding compelling evidence for this idea across several analysis approaches and across two independent samples. This is an important paper that will be of interest to a broad group of learning, memory, and decision-making researchers.

eLife assessment

The authors use an elegant design to tackle a longstanding question about the extent to which learning social information relies on specialized computational and neural mechanism. They find that learning about ostensible others is more accurate than learning about non-social objects, despite identical statistical information, and that such effects are mediated by the dmPFC and pTPJ - regions previously implicated in social cognition. While likely of interest to a broad range of social, behavioral, and cognitive neuroscientists, the work is not sufficiently framed by relevant previous research. Moreover, the difference between social (faces) and non-social (fruits) stimuli raises concerns about attentional confounds.

eLife assessment

This interesting manuscript assesses calcium dynamics in the kisspeptin neurons of the arcuate nucleus of the hypothalamus during the estrous cycle and during reproductive aging in female mice. In particular, the authors succeed in tracking arcuate kisspeptin calcium activity in the same mice over 10 months, which is quite impressive and provides novel findings that will be of interest to the field.

eLife assessment

This study provides convincing evidence supporting the important finding that acoustic and linguistic features contribute to brain responses as people listen to speech. However, the innovation of the methodological advance relative to other papers in the subfield is not entirely clear.

eLife assessment

Tan and colleagues studied synaptic transmission, presynaptic protein levels, and synaptic ultra-structure in hippocampal cultures of mice lacking the key active-zone proteins RIM (1, 2), ELKS (1, 2), and Munc13 (1, 2). Compared to cultures lacking only RIM and ELKS, additional deletion of Munc13 results in a further decrease of synaptic Munc13-1 levels, a similar reduction of the number of docked synaptic vesicles, and a more pronounced decrease of total synaptic vesicle number. At the physiological level, these RIM-ELKS-Munc13 hextuple knockout cultures display a further decrease in the pool of release-ready synaptic vesicles with largely unchanged release probability compared with RIM-ELKS quadruple KO cultures. The results support the conclusion of the nonredundant role of Munc13 in synaptic vesicle priming. On the other hand, while the genetic removal of all six genes involved clearly require the use of conditional KO mice, the resulting outcome of the experimental design is a hypomorphic phenotype, as neurotransmitter release is still detected and this complicates the interpretation of the findings. Overall, this study reinforces the notion that synapse formation is a remarkably resilient process that occurs even under strong perturbation of presynaptic function.

eLife assessment

This manuscript makes a major contribution to the study of early visual representation in primates by showing that intermediate cortical areas V2 and V4, as well as primary cortical area V1 (previously shown), contain orthogonal maps of orientation and spatial frequency, which are recursive across the visual field representation. This is a fundamental principle of functional mapping across the two-dimensional cortical surface that ensures and optimizes the complete representation of all combinations across two coding dimensions.

eLife assessment

This paper deploys elegant genetic tools to understand how synapses are formed in the Drosophila central nervous system. The synaptic connections between two identified neurons in the Drosophila central nervous system are used as a system to document the role of cell ablation and activity in dendrite growth and circuit wiring. In so doing, they identify a brief window of time that appears critical for these wiring and growth decisions.

eLife assessment

This paper is expected to be of interest to systems neuroscientists in the fields of emotion, hippocampal function, and anxiety-related behavior. The authors performed recordings in ventral hippocampus and show that 1) place fields become concentrated near the open areas of a maze, 2) direction-dependent coding decreases in these open areas, and 3) ventral hippocampal population activity in the closed area can be used to predict how mice explore the open area in the immediate future. These valuable findings support a potential role for the ventral hippocampus in the exploration of anxiety-provoking environments, however, the manuscript in its current form is incomplete, with some support for the main findings but also some limitations.

eLife assessment

This is a useful study exploring multi-modality brain age (structural plus resting state MRI) in people in the early stages or at risk of Alzheimer's disease. They found solid evidence that people with cognitive impairment had older-appearing brains and that older-appearing brains were related to Alzheimer's risk factors such as amyloid and tau deposition. They claim to show that the multi-modality brain age model is more accurate than a unimodal structural MRI model, though the evidence for that is incomplete.

eLife assessment

This is an important and fundamental, well-written and easily comprehended quantitative imaging study, analyzing the motion of endo-lysosomal compartments within axons in vivo using simultaneous multiphoton imaging in the mammalian brain. Taken together, this is a significant technical advance with interesting observations that substantively move the field forward.