Distinct functional classes of CA1 hippocampal interneurons are modulated by cerebellar stimulation in a coordinated manner.

Acute manipulation of the cerebellum can affect the activity of cells in CA1, and perturbing normal cerebellar functioning can affect hippocampal-dependent spatial processing, including the processing of objects in space. Despite the importance of interneurons on the local hippocampal circuit, it was unknown how cerebellar activation impacts CA1 inhibitory neurons. We find that stimulating the cerebellum robustly affects multiple populations of CA1 interneurons in a bidirectional, coordinated manner, according to their functional profiles during behavior, including locomotion and object investigations. Our work also provides support for a role of CA1 interneurons in spatial processing of objects, with populations of interneurons showing altered activity during object investigations.