Effect of Rapid Kindling on Hippocampal Single-Unit Recordings

GORI B; GALARDI M; BATAGLIA G; KOCHEN S

SINGAPUR

Conferencia; 1st International Brain Stimulation Conference; 2015

Objective: Epileptic seizures are sudden changes in neural activity that interfere with the normal functioning of the neural network, expressed through hypersynchronic discharges. There are several experimental models of epilepsy, one of which is Kindling, probably the most widely accepted experimental model for mesial temporal lobe epilepsy (MTLE). Hippocampal Rapid Kindling derives from traditional kindling, but is considered a more practical experimental model because it renders fully klindled animals in a shorter period of time. After our experience with hippocampal RK, we wondered how the single neuronal activity would be affected during the RK process. Methodology: Male Wistar rats were implanted with a bipolar macroelectrode in the CA1 region of right ventral hippocampus, through which they were kindled. Also, eight single microelectrodes were placed in the CA1 region of right dorsal hippocampus. Single-unit activity was recorded and characterized during ictal and interictal periods of kindled seizures. Electroencephalographic signals (EEG) and local field potentials (LFP) were correlated to analyze the ictal activity in ventral and dorsal right hippocampus. Results: Microseizures, as fast and synchronized discharges, were observed in LFP recordings while they were not observed in EEG signal from macroelectrode. This suggests that epileptiform activity would begin from micrometric scale before recruiting sufficient neuron populations to be detectable on macroelectrode. Conclusion: The combined study of these parameters allows us to assess more precisely the dynamic changes involved in epileptogenic networks. This study is funded by UBACYT, University of Buenos Aires