An examination of Kindling's effect on spatial cognition

• Main Author: Wolfe, Kenneth Joseph
• Other Authors: Tuchek, John M.
• Format: Others
• Language: en
• Published: University of Saskatchewan 2003
• Subjects: hippocampus; rat; spatial memory; kindling; behavior; entorhinal cortex
• Online Access: http://library.usask.ca/theses/available/etd-11172003-090025/

Kindling involves the progressive development of epileptiform activity that culminates in generalized seizures in response to repeated electrical stimulation of the brain. Kindling induces widespread changes in synaptic sensitivity and neuronal reactivity. These neuroplastic changes are evident in altered memory and behavior. This research was designed to further our understanding of kindling-induced deficits in spatial cognition. Two questions were examined: 1)does entorhinal cortex kindling disrupt spatial cognition; and 2)can bilateral bifocal kindling, of two brain regions known to participate in spatial cognition, produce larger cognitive deficits than unifocal kindling? This research attempted to confirm the spatial cognitive effects produced by unifocal dorsal hippocampal (dHPC) kindling, as a positive control. In contrast, the spatial cognitive effects produce by unifocal entorhinal cortex (EC) and bifocal kindling (i.e., EC kindling with subsequent contralateral dHPC kindling) are unknown and were examined here. Rats were subjected to unifocal EC kindling, unifocal dHPC kindling, or bifocal kindling. Rats exhibited fully generalized seizures prior to Morris water maze training from days 2 to 31. Visible platform trials were used to examine escape motivation and gross motor coordination, and all groups performed adequately. Consistent with previous research, dHPC kindling disrupted performance during acquisition trials; however, EC and bifocal kindling failed to disrupt acquisition. During retention trials, the bifocal kindling group displayed a disruption in performance; however, dHPC and lateral EC kindling failed to affect retention. The bifocal kindled group failed to display larger deficits than the unifocal kindled groups. These data suggest that the number of kindling stimulations given to a particular site may play a critical role in site-dependent disruption of memory.