Pattern of projection and physiological properties of cortico-cortical connections from the posterior bank of the ansate sulcus to the motor cortex, area 4?, in the cat

Abstract
The physiological properties of neurons lying along the posterior bank of the ansate sulcus and the projection of these neurons to area 4γ of the motor cortex of the cat were studied and the following results were obtained: (1) Short latency antidromic responses were recorded from neurons along the medial-lateral bank of the posterior ansate sulcus following intracortical microstimulation (ICMS) delivered to motor cortex, area 4γ. (2) The posterior ansate region projects topographically to the motor cortex. Neurons in the most medial part of the ansate region project to the medial part of 4γ, while neurons in the central and lateral parts of the ansate region project to the more lateral parts of area 4γ. (3) In 33 cases, receptive field information was available for both the antidromically activated ansate neuron and from neurons around the stimulating site in 4γ. In 58% of the cases, both cortical sites received afferent input from within the same part of the periphery. (4) Afferent input to the motor cortex was examined following combined ablations of the primary somatosensory cortex (SI) and third somatosensory cortex (SIII) including all of area 5. We conclude that the integrity of these cortical regions is not necessary for afferent input to reach the motor cortex.