Piracetam and brain excitability. An electrophysiological study in cats.

The effect of piracetam on the excitability of the brain has been examined in cats by electrophysiological approaches: spontaneous electrocorticogram (ECoG), visual evoked potentials (VEPs) and their recovery cycles in some brain structures (visual and associative cortex, lateral geniculate body, centrum medianum thalami and mesencephalic reticular formation). Piracetam (100 mg/kg i.v.) increased the spectral power of ECoG and particularly in the associative cortex for the frequency bands of 10-12 and 19-22 Hz. Piracetam decreased the early components and facilitated the late components of VEPs predominantly in the associative cortex. Changes were found in the recovery cycles too, namely, facilitation and shortening of recovery in all structures studied except in lateral geniculate body. The data suggest that piracetam acts as a non-specific activator on the excitability thus optimizing the functional state of the brain.