Abstracts

Modifications of pyramidal and interneuronal network in neurological disorders are correlated by shape waves and rhythms from electroencephalogram (EEG). Unfortunately how this network participates in epileptogenesis is not yet clear., Kindling protocol is achieved by stimulating six times daily during 4 days with sub-convulsive electrical stimulations in the dorsal right hippocampus using bipolar electrode units. Spikes and behavioral responses are quantified in order to confirm the progress of kindling. The EEG obtained is recorded using Enhanced Graphics Acquisition for Analysis (RS Electronics Inc.) and offline sort spikes (Plexon Inc.), and analyzed using Neuroexplorer Software (Next Technology) (Musto and Bazan, 2006, Epilepsia, 47:267-76)., Spikes and semiological score increase during kindling. Different patterns are discriminated within afterdischarge. A spike-wave pattern appears immediately after the stimulation in combination with a poly-spike complex superimposed over the wave (AD1) and it is followed by another poly-spike complex (AD2). AD2 is followed by a progressive modification of synchronized spikes (AD3). The spreading depression like event (SD) is present at the end of each AD3. Theta oscillation predominates since the first two days of kindling and apparition of significative gamma oscillation is observed within AD2 and precedes the full kindled state., Pyramidal-interneuron network could work properly immediately after each stimulation and could be necessary, but not sufficient for epileptogenesis. The trigger of this oscillation could lead to a mechanism of desynchronisation and synchronism within neuronal network during epileptogenesis. Since a gamma rhythm precedes the generalized seizure, this could be a target for therapeutic intervention., (Supported by NIH Grant: NS 23002.)