RT Journal Article
SR Electronic
T1 The Hippocampus and Disambiguation of Overlapping Sequences
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 5760
OP 5768
DO 10.1523/JNEUROSCI.22-13-05760.2002
VO 22
IS 13
A1 Agster, Kara L.
A1 Fortin, Norbert J.
A1 Eichenbaum, Howard
YR 2002
UL http://www.jneurosci.org/content/22/13/5760.abstract
AB Recent models of hippocampal function emphasize its potential role in disambiguating sequences of events that compose distinct episodic memories. In this study, rats were trained to distinguish two overlapping sequences of odor choices. The capacity to disambiguate the sequences was measured by the critical odor choice after the overlapping elements of the sequences. When the sequences were presented in rapid alternation, damage to the hippocampus, produced either by infusions of the neurotoxin ibotenic acid or by radiofrequency current, produced a severe deficit, although animals with radiofrequency lesions relearned the task. When the sequences were presented spaced apart and in random order, animals with radiofrequency hippocampal lesions could perform the task. However, they failed when a memory delay was imposed before the critical choice. These findings support the hypothesis that the hippocampus is involved in representing sequences of nonspatial events, particularly when interference between the sequences is high or when animals must remember across a substantial delay preceding items in a current sequence.