Hippocampal sequence-encoding driven by a cortical multi-item working memory buffer

Trends Neurosci. 2005 Feb;28(2):67-72. doi: 10.1016/j.tins.2004.12.001.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Cerebral Cortex / physiology*
  • Hippocampus / physiology*
  • Humans
  • Long-Term Potentiation / physiology
  • Memory, Short-Term / physiology*
  • Models, Neurological
  • Neurons / physiology*