Specific and nonspecific changes in visual evoked potentials during eyelid conditioning in the rabbit (Oryctolagus...

Eye blinks were conditioned to either the visual or nonvisual element of a compound conditioned stimulus. The visual element consisted of a series of electrical pulses to the optic chiasma, and the averaged evoked potentials (AEPs) produced by this stimulus were recorded in the dorsal lateral geniculate nucleus and the visual cortex. The initial surface positive component of the cortical AEP was enhanced only when the eye blinks were conditioned to the visual stimulus, an effect that cannot be attributed to nonspecific mechanisms. The "postsynaptic" component of the geniculate AEP was also enhanced, but this occurred regardless of whether the eye blinks were conditioned to the visual or nonvisual stimulus, an effect that appears to be entirely nonspecific. Data from recovery cycles indicate that this enhancement effect cannot be attributed to an inhibition of inhibitory interneurons in the lateral geniculate nucleus.