Eichenbaum Lab Research Summary T he hippocampus plays a critical role in memory formation, but our understanding of just what the hippocampus does and how it performs its functions are still issues of considerable controversy. In an effort to clarify what aspects of memory depend on the hippocampal system, we are studying the effects of experimental damage to components of that system on different types of learning and memory. Our recent efforts suggest that the parahippocampal cortical region may play a particularly important role in the extended storage of representations of items and events, and that the hippocampus itself may process and mediate storage of critical relationships among items and events, permitting the flexible use of memories in novel situations. A schematic model of the transitive inference task.
Cups filled with scented sand serve as the discriminative cues.
The cups are presented to animals in the four pairings seen here with one cup rewarded in each pair. Parallel studies that involve electrophysiological recordings from single neurons in animals performing learning and memory tasks are employed to determine what aspects of learning are encoded by the hippocampus. These findings complement the data from our neuropsychological studies, supporting the view that the hippocampus helps instantiate a network of memories. Current efforts are directed at how the hippocampus mediates the coding and storage of events in neocortical areas with which it is reciprocally connected, and at how the coding of information is distributed within the hippocampus . This cell fired when trials were performed at adjacent locations P2-P3, but not when the trial was performed at other locations.