A Virtual Reality Platform for Context-Dependent Cognitive Research in Rodents / 神经科学通报·英文版

Animal survival necessitates adaptive behaviors in volatile environmental contexts. Virtual reality (VR) technology is instrumental to study the neural mechanisms underlying behaviors modulated by environmental context by simulating the real world with maximized control of contextual elements. Yet current VR tools for rodents have limited flexibility and performance (e.g., frame rate) for context-dependent cognitive research. Here, we describe a high-performance VR platform with which to study contextual behaviors immersed in editable virtual contexts. This platform was assembled from modular hardware and custom-written software with flexibility and upgradability. Using this platform, we trained mice to perform context-dependent cognitive tasks with rules ranging from discrimination to delayed-sample-to-match while recording from thousands of hippocampal place cells. By precise manipulations of context elements, we found that the context recognition was intact with partial context elements, but impaired by exchanges of context elements. Collectively, our work establishes a configurable VR platform with which to investigate context-dependent cognition with large-scale neural recording.

Segregated Cell Populations Enable Distinct Parallel Encoding within the Radial Axis of the CA1 Pyramidal Layer

Numerous studies have implicated the hippocampus in the encoding and storage of declarative and spatial memories. Several models have considered the hippocampus and its distinct subfields to contain homogeneous pyramidal cell populations. Yet, recent studies have led to a consensus that the dorso-ventral and proximo-distal axes have different connectivities and physiologies. The remaining deep-superficial axis of the pyramidal layer, however, remains relatively unexplored due to a lack of techniques that can record from neurons simultaneously at different depths. Recent advances in transgenic mice, two-photon imaging and dense multisite recording have revealed extensive disparities between the pyramidal cells located in the deep and the superficial layers. Here, we summarize differences between the two populations in terms of gene expression and connectivity with other intra-hippocampal subregions and local interneurons that underlie distinct learning processes and spatial representations. A unified picture will emerge to describe how such local segregations can increase the capacity of the hippocampus to compute and process numerous tasks in parallel.

The Deterioration of Spatial Memory and the Role of the Masticatory Function during Aging: A Brief Literature Review.

This article reviews the current state of scientific information on the relationship between the deterioration of spatial memory and the role of the masticatory function, both of which are primarily examined during the aging process. The article broadly examines the current notions regarding neuroscientific processing mechanisms of spatial memory. Additionally, some variables that produce alterations in hippocampal function during aging are presented here. Finally, the role that mastication fulfills as an emerging physiological mechanism of cognitive impairment compensation is discussed. This article concludes that, despite the recent progress in understanding the concepts presented in this article, evidence suggests that there are still many questions to be answered. These questions are sustaining the growing interest in the field of neuroscience in examining the underlying mechanisms of the intricate process of spatial orientation and their relation to masticatory function in aged organisms.