Time: 10: 00 -11: 00 on Monday, Mar. 12,?2018
Venue: B323, Medical Science Building, Tsinghua University

Dr. Yi Gu
Postdoctoral fellow, Princeton Neuroscience Institute, Princeton University

Host: Dr. Zengcai Guo

Abstract:
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.