| Abstract No.: | C-B3050 |
| Country: | Canada |
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| Title: | PHASE RELATION OF SLOW OSCILLATIONS TO EPILEPTIFORM ACTIVITIES IN THE HIPPOCAMPUS |
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| Authors/Affiliations: | 1 Farhang Nazer*; 1 Clayton Dickson;
1 University of Alberta, Edmonton, AB, Canada
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| Content: | Objectives: We have previously shown that spontaneous epileptiform activities (SEA) in hippocampus (HPC) are more abundant during rhythmic slow oscillations (SO). However, because of the rapid propagation of SEA to other brain structures, we were not able to investigate the phase relationship of SEA to SO. With induction of SEA in ipsilateral rat HPC and simultaneous recording of SO in the contralateral HPC, we have observed significant phase modulation patterns.
Materials & Methods: Experiments were conducted in acutely urethane-anaesthetized rats undergoing spontaneous state changes. Penicillin potassium was microinjected into one HPC while recording the rapid-generating SEA using local field potential methods bilaterally. Sections of uncontaminated EEG from the contralateral site containing SO was selected and filtered between 0.5Hz to 1.5Hz. This was used as a cyclic process to group the occurrence of spikes in the ipsilateral side in order to test for any significant phase relationship of SEA to the SO.
Results: SEAs tended to occur predominantly during the up-state of slow oscillations (significantly phase related using Raleigh phase angle test).
Conclusion: Our results suggest that the cyclicity of rhythmic HPC SO can modulate the occurrence of SEA activity. This could be another way in which the SO might promote epileptiform activity in hippocampus.
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