Hippocampal sequence-encoding driven by a cortical multi-item working memory buffer.
Encoding and recall of memory sequences is an important process. Memory encoding is thought to occur by long-term potentiation (LTP) in the hippocampus; however, it remains unclear how LTP, which has a time window for induction of approximately 100 ms, could encode the linkage between sequential items that arrive with a temporal separation >100 ms. Here, we argue that LTP can underlie the learning of such memory sequences, provided the input to the hippocampus is from a cortical multi-item working memory buffer in which theta and gamma oscillations have an important role. In such a buffer, memory items that occurred seconds apart are represented with a temporal separation of 20-30 ms, thereby bringing them within the LTP window. The physiological and behavioral evidence for such a buffer will be reviewed.
Jensen
Ole
O
FC Donders Centre for Cognitive Neuroimaging, PO Box 9101, NL-6500 HB Nijmegen, The Netherlands.
Lisman
John E
JE
D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D006801:Humans; D017774:Long-Term Potentiation / Q000502:physiology; D008570:Memory, Short-Term / Q000502:physiology*; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*