Bicuculline enhances a negative component and diminishes a positive component of the visual evoked cortical potential in the cat.

Publisher Website
Google Scholar
Abstract
Visual evoked potentials (VEP), elicited by modulation of luminance of homogeneous fields of light, were recorded from the scalp and from the surface of the visual cortex of cats before and after topical application of bicuculline to the cortex. The application of this drug drastically altered the VEP; the amplitude of a normally small negative component was increased greatly and a normally prominent late positive component was diminished. Bicuculline blocked the action of GABA, which was presumably the primary inhibitory neurotransmitter in the visual cortex. The affected negative wave apparently reflects an excitatory process in the visual cortex and the affected late positive wave reflects an intracortical inhibitory process.