Differential behavior-related activity of distinct hippocampal interneuron types during odor-associated spatial navigation

Hippocampal pyramidal cells represent an animal's position in space together with specific contexts and events. However, it is largely unknown how distinct types of GABAergic interneurons contribute to such computations. We recorded from the intermediate CA1 hippocampus of head-fixed mice exhibiting odor-to-place memory associations during navigation in a virtual reality (VR). The presence of an odor cue and its prediction of a different reward location induced a remapping of place cell activity in the virtual maze. Based on this, we performed extracellular recording and juxtacellular labeling of identified interneurons during task performance. The activity of parvalbumin (PV)-expressing basket, but not of PV-expressing bistratified cells, reflected the expected contextual change in the working-memory-related sections of the maze. Some interneurons, including identified cholecystokinin-expressing cells, decreased activity during visuospatial navigation and increased activity during reward. Our findings suggest that distinct types of GABAergic interneuron are differentially involved in cognitive processes of the hippocampus.

Automated summary

Hippocampal pyramidal cells represent an animal's position in space together with specific contexts and events. How different types of GABAergic interneurons contribute to these computations is largely unknown. In this study, we recorded and labeled identified interneurons in the intermediate CA1 hippocampus of mice navigating in a virtual reality (VR) maze. Our findings suggest that PV-expressing basket cells reflect contextual changes in the working-memory-related sections of the maze, while some interneurons, including cholecystokinin-expressing cells, show decreased activity during visuospatial navigation and increased activity during reward.