时  间：   2018年3月12日 10:00-11:00

地  点：   清华大学医学科学楼B323

讲座嘉宾：谷一（普林斯顿大学博士后）

主持人：郭增才, 清华-IDG/麦戈文脑科学研究院研究员

题目：A topographical map of space: micro-organization of grid cells in the medial entorhinal cortex

摘要：Topographical maps are remarkable features of brain structure, in which the anatomical organization of neurons corresponds to specific properties of the variables they encode. Although it is still unclear how topographical maps relate to functional mechanisms, they have been observed in many sensory and motor systems, such as the retinotopic map in primary visual cortex and the somatotopic map in somatosensory cortex. However, topographical maps for cognitive variables are rarely reported.
In the current study, we discovered the first fine-scale topographical map in a high-level cognitive cortical circuit in the rodent brain. Using cellular-resolution two-photon calcium imaging during virtual navigation, we investigated the relationship between the anatomical organization and functional properties of grid cells, which represent a cognitive code for location during spatial navigation. We found a substantial degree of grid cell micro-organization in mouse medial entorhinal cortex: grid cells and modules all clustered anatomically. Within a module, the layout of grid cells was a noisy two-dimensional lattice, in which the anatomical distribution of grid cells largely matched their spatial tuning phases. This map of grid cells contributes to a foundation for evaluating circuit models of the grid cell network, and is consistent with continuous attractor models as the mechanism of grid formation. The relationship between the anatomical distribution of grid cells and their function in mouse MEC demonstrates how topography and function can be intimately related in neural circuits.