The Journal of Neuroscience, June 15, 2001, 21(12):4443-4450
Dorsal Hippocampal Kindling Produces a Selective and Enduring
Disruption of Hippocampally Mediated Behavior
Darren K.
Hannesson1,
John
Howland2,
Michael
Pollock3,
Paul
Mohapel4,
Amy E.
Wallace1, and
Michael E.
Corcoran1
1 Departments of Psychology and Psychiatry,
Neuropsychiatric Research Unit, University of Saskatchewan, Saskatoon,
Saskatchewan, Canada S7N 5E4, 2 Department of Psychology,
University of British Columbia, Vancouver, British Columbia, Canada V6T
1Z4, 3 Department of Psychology, Simon Fraser University,
Vancouver, British Columbia, Canada V5A 1S6, and 4 Section
of Restorative Neurology, Wallenberg Neuroscience Center, University
Hospital, S-221 85 Lund, Sweden
Kindling produces enduring neural changes that are subsequently
manifest in enhanced susceptibility to seizure-evoking stimuli and
alterations in some types of behavior. The present study investigated the effects of dorsal hippocampal (dHPC) kindling on a variety of behaviors to clarify the nature of previously reported effects on
spatial task performance. Rats were kindled twice daily with dHPC
stimulation until three fully generalized seizures were evoked. Beginning 7 d later and on successive days, rats were tested in an
elevated plus maze, a large circular open field, an open field object
exploration task, and a delayed-match-to-place (DMTP) task in a water
maze to assess anxiety-related and activity-related behavior (tasks 1 and 2), object recognition memory (task 3), and spatial cognition (task
4). Kindling disrupted performance on the DMTP task in a manner that
was not delay dependent and produced a mild enhancement of
activity-related behaviors in the open field task but not the elevated
plus maze. All other aspects of testing were spared. These findings
indicate that dHPC kindling produces enduring and selective effects on
behavior that are consistent with a restricted disruption of
hippocampally mediated functions. Possible bases for these effects are
changes in local NMDA receptor function and/or changes in local
inhibition, which might alter the optimal conditions for
experience-dependent induction of intrahippocampal plasticity. This
preparation may be useful for studying the mechanisms of mnemonic
dysfunction associated with temporal lobe epilepsy and may offer unique
insights into the mechanisms underlying normal hippocampal function.
Key words:
activity; anxiety; CA1; DMTP; elevated plus maze; epilepsy; epileptogenesis; exploration; object recognition; open field; spatial; water maze
Copyright © 2001 Society for Neuroscience 0270-6474/01/21124443-08$05.00/0