| Abstract No.: | A-C1086 |
| Country: | Canada |
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| Title: | DORSAL PERIAQUEDUCTAL GREY KINDLING INDUCES CONDITIONED PLACE AVERSION AND CONTEXT INDEPENDENT ANXIETY-LIKE BEHAVIOUR |
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| Authors/Affiliations: | 1 Ann Lam*; 1 Joelle Nadeau; 1 Michael Corcoran;
1 University of Saskatchewan, Saskatoon, SK, Canada
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| Content: | Objectives: We have previously reported that during kindling of brainstem sites rats appear to be distressed before stimulation is applied, often audibly vocalizing and freezing when placed in the stimulation chamber. To investigate whether brainstem site kindling involves conditioning of fearful responses in rats we employed a place-conditioning paradigm modeled after Barnes and Pinel [1]. We also included ictal measures as previously described by Wagner and Corcoran to examine the effects of conditioning on the characteristics of kindling [2].
Materials and Methods: Eighteen male Long Evans rats received 16 pairings of dorsal periaqueductal grey (dPAG) kindling or sham stimulation in distinctive contexts (CS+ and CS-, respectively) before a conditioned place preference/aversion test, to determine whether the stimulation and seizures were rewarding or punishing. After 16 more pairings, rats received kindling stimulation in the other context (switch test). Ictal measures in this test included afterdischarge duration, clonus duration, latency to clonus, class of convulsion, and falls. After four additional pairings, afterdischarge threshold (ADT) was measured in each context. The rats' behaviour in the prestimulation interval was recorded daily to measure conditioned anticipatory defensive behaviour. Electrode placements were verified at the end of the study, and only rats with electrodes correctly placed in the dPAG were used for analysis.
Results: When tested for conditioned place preference, rats spent a significantly greater percentage of time in the CS- relative to the CS+. Rats also were more active in the CS- than in the CS+. There was no difference in ADT in the CS+ and CS-. The intensity of behavioural convulsions also did not differ in the two contexts.
Conclusions: We demonstrated that rats display a conditioned place aversion to the kindling environment and that anticipatory anxiety-like behaviour is globally elevated after dPAG kindling. However, there were no conditioned effects on any ictal measures. Thus dPAG kindling induces anxiety-like behaviour in rats, and the conditioning of behavioural responses does not appear to affect seizure susceptibility.
1. Barnes, S.J. and J.P. Pinel, Conditioned effects of kindling. Neurosci Biobehav Rev, 2001. 25(7-8): p. 745-51.
2. Wagner, J.P. and M.E. Corcoran, Conditioning of interictal behaviours, but not ictal behaviours, seizures or afterdischarge threshold, by kindling of the amygdala in rats. European Journal of Neuroscience, 2008. 27(1): p. 169-176. |
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