Motion sensitive cells in the macaque superior temporal polysensory area. I. Lack of response to the sight of the animal's own limb movement.

An animal's own behaviour can give rise to sensory stimulation that is very similar to stimulation of completely external origin. Much of this self-induced stimulation has little informative value to the animal and may even interfere with the processing of externally induced stimulation. We have measured responses of visual movement sensitive neurons in the anterior part of the dorsal superior temporal sulcus of monkeys to stimulation caused by the animal's own active movements. These cells responded to any stimuli moved by the experimenter, but gave no response to the sight of animal's own limb movements. The cells remained responsive to external stimulation, however, while the monkey's own hand was moving in view. Responses to self-induced movements were recovered if the monkey introduced a novel object in its hand into view. Various possible neural mechanisms for explaining the results are discussed, and it is suggested that the studied neurons belong to a system that detects unexpected and hence behaviourally relevant sensory events.