LOCALIZING FUNCTIONAL-ACTIVITY IN THE BRAIN THROUGH TIME-FREQUENCY ANALYSIS AND SYNTHESIS OF THE EEG

Multichannel electroencephalograms (EEG's) are processed using time-fr equency (TF) analysis and synthesis techniques to geometrically locali ze neuroelectric generators of specific activity contained within the observed EEG. The TF domain techniques are utilized to separate the si gnals of interest from the remainder of the EEG, by allowing the defin ition of regions of interest,which contain the signals for which we de sire to localize the underlying neuronal generators. This approach ess entially introduces a filtering technique which allows the distortionl ess separation of the signals of interest from all other components re corded. The source of the functional activity in the brain is estimate d and mapped numerically by a least-squares approach. We have applied these techniques to identify the anatomical location of the sleep spin dle, a component of the EEG observed during sleep, which is of importa nce in understanding the generation of sleep and sleep patterns.