Memory consolidation: Systems

Memories of facts and events can last a lifetime, but the neural substrates of these memories are not static. Neuronal modification and more effective storage may result from hippocampal-cortical interactions during walking as well as during sleep. Hippocampal networks can function to conjointly activate a spatially distributed set of storage locations in the cerebral cortex. Whereas memory retrieval initially depends on both hippocampal and cortical networks, following consolidation neocortical networks can be sufficient for memory retrieval, though sometimes these memories lack contextual detail. Important questions remain about how declarative memories are represented, how consolidation operates on these representations, and how defective consolidation can cause retrograde amnesia.