Hebbian plasticity in parallel synaptic pathways: A circuit mechanism for systems memory consolidation
Michiel Remme †, Urs Bergmann †, Denis Alevi, Susanne Schreiber, Henning Sprekeler †, Richard Kempter († equal contribution)
Systems memory consolidation involves a transfer of declarative memories that initially depend on the hippocampal formation into long-term memory traces in neocortical networks. This consolidation process is thought to rely on replay of recently acquired memories, but the cellular and network mechanisms that mediate the memory transfer are poorly understood. Here, we suggest that systems memory consolidation could arise from Hebbian plasticity in networks with parallel synaptic pathways — two ubiquitous features of neural circuits in the brain. We explore this hypothesis in a computational model to illustrate how memories are transferred across circuits and why their representations could change. These modelling results are in quantitative agreement with lesion studies in rodents. A hierarchical iteration of the mechanism yields power-law forgetting — as observed in psychophysical studies in humans. The predicted circuit mechanism thus bridges spatial scales from single cells to cortical areas and time scales from milliseconds to years.