The neural substrates of memories and decisions. The abilities to learn, remember, plan, and decide are central to who we are. These abilities require that memories be stored, retrieved, and then used to guide decision-making. Current theories suggest that memories are stored when specific patterns of neural activity cause changes in the connections among neurons, and memories are retrieved when these patterns are reinstated. While we have some idea of the brain regions required for these processes, we lack a deep understanding of how memories are created, remembered, and used. Our team and others have found a phenomenon—termed sharp-wave ripple events—that contributes to memory retrieval and memory-guided planning. Studying this phenomenon in rats, we have already developed advanced decoding algorithms that can determine the content—i.e., the memory being retrieved—from different patterns of neural activity. But to truly understand memory retrieval, we need to move beyond simple observation to the manipulation of neural circuits. To do this, we will combine new real-time decoding algorithms with technology for monitoring and manipulating the activity of many neurons at once. Because we can decode which memory is being retrieved, we will be able to selectively disrupt retrieval of that memory while leaving other brain processes unaffected. These experiments will make it possible to understand how the disruption of specific memory events affects the processing of those events in brain regions and thereby alters the animal’s behavior.
Loren Frank, University of California, San Francisco
Uri Eden, Boston University