Title
Robust information routing by dorsal subiculum neurons.
Speaker
Kenji Mizuseki, M.D., Ph.D.
Department of Physiology, Osaka City University Graduate School of Medicine
Summary
The hippocampus is critical for both spatial navigation and memory. Since the discovery of place cells (O’Keefe and Dostrovsky, 1971), numerous studies have measured hippocampal neuronal activity and have established that this brain area conveys multimodal information associated with spatial navigation, including place, speed, and trajectory. Such information should be distributed to extra-hippocampal areas to support navigation. However, how the diverse information is distributed to downstream areas remains largely unknown.
We investigated how information coded in the hippocampus is distributed to downstream areas via its major output structure, the subiculum. To this end, we combined multi-site optogenetics and large-scale extracellular recordings to map the projections of rats’ subicular neurons while monitoring the neuronal activity from the subiculum and hippocampal CA1 area during different spatial tasks. Key features of spatial information, such as place, speed, and trajectory were accurately represented by subicular neurons in a noise-resistant manner. Speed and trajectory information was routed to the retrosplenial cortex and nucleus accumbens, respectively, while place information was uniformly distributed to the retrosplenial cortex, nucleus accumbens, anteroventral thalamus, and medial mammillary body. Our results indicate that the subiculum generates noise-resistant, accurate representations for multiple types of spatial navigation-associated information and distributes this information uniformly or selectively to downstream areas depending on the type of information.
References
Kitanishi T, Umaba R, Mizuseki K. (2020) Robust information routing by dorsal subiculum neurons. bioRxiv. https://doi.org/10.1101/2020.06.04.133256
Iwase M, Kitanishi T, Mizuseki K (2020) Cell type, sub-region, and layer-specific speed representation in the hippocampal–entorhinal circuit. Sci Rep 10: 1407.
Mizuseki K, Miyawaki H (2017) Hippocampal information processing across sleep/wake cycles. Neurosci Res 118, 30-47.
