Responsiveness of cat lateral geniculate at pre- and postsynaptic levels during natural sleep

Abstract

Abstract Using cats carrying permanently implanted electrodes, responsiveness of the lateral geniculate body (LGB) was studied during sleep and wakefulness. The postsynaptic discharges in response to stimulation of the optic tract (OT) were smallest during light sleep and increased during deep sleep. The responses during resting wakefulness were intermediate between those during light and deep sleep. Responsiveness of the presynaptic terminals was measured by recording antidromically conducted OT spikes to stimulation of the terminals with the LGB electrodes. It is suggested that the state of deep sleep provides the LGB with a more intense presynaptic inhibition than does the state of light sleep. The deep sleep wave, a peculiar spontaneous activity seen in the LGB during deep sleep, was found to intensify phasically facilitation at the postsynaptic level and also inhibition at the presynaptic level.