Synapse-specific plasticity governs the identity of overlapping memory traces
(Japan Science and Technology Agency) Each memory is stored in a specific population of neurons called engram cells. When a memory is linked with another to generate an associative memory, two memory traces overlap. At the same time, individual memories maintain their own identities. Using two overlapping fear memories in mice, researchers show that synapse-specific plasticity guarantees both storage and identity of individual memories. They also show that memory traces no longer exist in the brain after complete retrograde amnesia.