[Postsynaptic mechanism of habituation of turtle cortical neurons to moving stimuli]

An investigation was made into the change in the amplitude of evoked potentials and intracellular slow potentials of the turtle general cortex units in response to a periodic movement of a monotonous stimulus, a black band, across the visual field. The recorded depression of responses possesses all the properties of habituation. The first presentations of the monotonous stimulus produce a generalized habituation, gradually replaced by a selective habituation to the monotonous stimulus, as the number of stimulations increases. It has been shown that it is possible to disinhibit the amplitudes of the evoked potentials and intracellular slow potentials of cortical neurones to moving black bands which form part of the monotonous stimulus. A conclusion has been drawn that habituation of the turtle cortical units to moving stimuli is due to a postsynaptic mechanism.