ABOLITION OF LONG-TERM STABILITY OF NEW HIPPOCAMPAL PLACE CELL MAPS BY NMDA RECEPTOR BLOCKADE

Hippocampal pyramidal cells are called place cells because Each cell t ends to fire only when the animal is in a particular part of the envir onment-the cell's firing field. Acute pharmacological blockade, of N-m ethyl-D-aspartate (NMDA) glutamate receptors was used to investigate h ow NMDA-based synaptic plasticity participates in the formation and ma intenance of the firing fields. The results suggest that the formation and short-term stability of firing fields in a new environment involv e plasticity that is independent of NMDA receptor activation. By contr ast, the long-term stabilization of newly established firing fields re quired normal NMDA receptor function and, therefore, may be related to other NMDA-dependent processes such as long-term potentiation and spa tial teaming.