NIH VideoCasting

Our research efforts are focused on investigating the neural correlates of human episodic memory formation by leveraging the opportunities to directly record neural activity across multiple spatial scales from the human brain in patients receiving surgical treatment for drug resistant epilepsy. At larger spatial scales, we find that both specific patterns of localized neural activity and dynamic connections between brain regions emerge as people encode individual items into memory, and similar patterns of activity and connectivity are reinstated when people retrieve those same items from memory. At the smallest spatial scale, we find that populations of individual neurons in the anterior temporal lobe exhibit temporally organized sequences of spiking activity that are specific to the individual items people are encoding into memory, and that similar sequences are replayed when people retrieve those items from memory. These sequences of spiking activity are distributed across spatially contiguous yet distinct functional modules that are approximately the same size as the cortical columns hypothesized to exist throughout the human brain, suggesting a functional organization to how information is encoded across neuronal populations. Together, our results provide novel insights into how information specific to individual memories is represented in the brain, and how this information is accessed as people recall previous experiences from memory.