Publisher Summary This chapter describes the recently observed features of the peripheral activation of identified corticocortical and thalamocortical neurons that project to the motor cortex. Two input pathways to the motor cortex were investigated in cats, one corticocortical and the other thalamocortical. Group I muscle afferents and cutaneous afferents of forelimb nerves project to cortical area 3a. Identified corticocortical neurons projecting to the motor cortex were among the neurons that these inputs activated. Some individual corticocortical neurons received convergent inputs from low threshold muscle and cutaneous afferents or inputs from dissimilar parts of the forelimb. Group II afferents of forelimb muscle nerves and cutaneous afferents also project to the motor cortex after extensive removal of the sensory cortex. Using horseradish peroxidase a projection to the motor cortex was identified from a “shell” around the rostral portion of the nucleus ventralis posterolateralis of the thalamus, at its border with the nucleus ventralis lateralis. Identified thalamocortical neurons of this border region received topographically organized inputs from skin or deep receptors of the forelimb. The evidence suggests that these two pathways may be involved in the control of the output of the motor cortex.