CORTICAL PROJECTION OF VENTROPOSTERIOR NUCLEUS OF THALAMUS IN CAT

The projection of the ventroposterior nucleus of the thalamus has been investigated in the cat using the Nauta technique. The nucleus may be subdivided into: (i) a large lateral component, corresponding to the ventrobasal complex47, which projects in a topographically organized manner to both the first (SI) and second (SII) somatic sensory areas of the cortex; and (ii) a smaller medial component, corresponding to a part of the ventromedial complex47, which projects to an area of cortex lying ventral to the face regions of both SI and SII and extending into the lateral bank of the presylvian sulcus. This portion of the nucleus and its cortical projection appear to be parts of the central pathway concerned with taste. Degeneration in SII is less intense than in SI and this is consistent with recent physiological evidence that only about half of the neurones in the ventrobasal complex project to both cortical areas. In SI, degeneration affects all architectonic subdivisions and in both areas terminal fragments are concentrated in layers I and IV, of the cortex. © 1969.