Shantanu Jahdav
Department of Psychology
“Neural activity patterns required for learning and memory-guided behavior”
We always hear that practice makes perfect and repetition builds mastery. But why? How does a brain learn? Dr. Jadhav’s research studies structures in the brain that effectively replay a behavior or memory during activity as well as during sleep. In order for learning to occur, it is critical that this neural activity pattern is not disrupted; in the presence of a disruption, learning is impaired.
The ability to form memories and use past experience to guide behavior is a remarkable capacity of the brain. The hippocampus and prefrontal cortex are critical structures involved in learning and memory. In rodents, hippocampal place cells are active during behavior both in the context of place fields during theta oscillations, where individual neurons fire in specific regions of space, as well as during sharp-wave ripples (SWRs), during which place cell sequences are replayed. To test the role of awake SWRs and associated replay processes in memory, these events were specifically disrupted in the hippocampus of awake behaving animals during spatial learning. This resulted in a specific impairment in a spatial working memory process that required linking temporally and spatially distant experiences. These results provide a crucial causal link between a specific hippocampal physiological pattern of activity and learning. Further, they also point toward a role of SWR-associated prefrontal activity in support of spatial working memory. Indeed, prefrontal activity is modulated distinctly by both awake SWRs as well as theta oscillations during learning, indicating that these network states represent fundamental modes of communication between the prefrontal cortex and hippocampus during behavior.