Ultra fast oscillations in the human brain and their functional significance

SUMMARY Human brain cell assemblies fire electrical impulses up to very high frequencies, which limit is not yet known. Using advanced intracranial microEEG recordings in a cohort of epileptic patients, we newly identified short-lasting oscillations in frequencies between 2 and 8 kHz. These ultra fast oscillations were consistently and locally detected in epileptic hippocampi but were extremely rare in non-epileptic brain tissue. The discovered electrophysiological phenomena thus may reflect neuronal hyperexcitability.