Motor deficit following interruption of sensory inputs to the motor cortex of the monkey

The possible functional role of sensory inputs in voluntary movements was examined by severing the sensory input pathways to the motor cortex. The somatic sensory cortex and the dorsal column, which are known to be the two major sources of the peripheral inputs to the motor cortex, were ablated or sectioned. The deficit produced by sensory cortex ablation or dorsal column section was not prominent and the function recovered within a week or two as long as the other input was intact, but elimination of both inputs produced severe impairment in movements such as loss of orientation in space and of manipulation of individual fingers. The possible role of the afferent input is discussed and it is proposed that it participates in the smooth pursuit of movement by continuously changing the excitability of cortical efferent zones.