Selective amplitude histograms: a statistical approach to EEG-single unit relationships in generalized epilepsy

Statistical analysis techniques that permit detection and quantification of EEG-single unit correlations were employed in a study of generalized penicillin epilepsy in the cat. Single unit activity was recorded in cerebral and cerebellar cortices and compared to the locally recorded EEG. It was found that during generalized paroxysmal activity the background EEG was significantly related to the time of occurrence of unit discharge. The degree of synchrony of various units differed but tended to increase as the duration and extent of paroxysmal activity increased. These relationships were usually not evident upon visual inspection of the original unprocessed data but were consistently detected by the analysis techniques described here. The results demonstrate the usefulness of a statistical approach to the analysis of single unit data and suggest that, not only is there a significant relationship between paroxysmal events and neuronal activity in generalized penicillin epilepsy, but also an overall trend to closer synchronization of EEG and single unit discharges during nonparoxysmal periods.