THALAMIC PROJECTION TO FRONTAL CORTEX IN MAN

Abstract

54 cerebral hemispheres with leucotomy, traumatic or vascular lesions were examined for retrograde nerve cell degeneration and glial proliferation in serial sections of the thalamus. The dorsomedial projects to the granular frontal cortex except from its most dorso-posterior portion, its most rostral tip and probably a portion of the pars magno-cellularis on its medial border. There is antero-posterior axial organization, the anterior small-celled part projecting to the rostral cortex, etc. The nucleus submedius projects to the same cortical field as the adjacent part of the dorsomedial nucleus. The centro-median, parafascicular and midline nuclei do not project to the frontal cortex. Agranular area 6 received fibers from dorsal and medial parts of the nucleus ventralis anterior and lateralis and probably from the adjacent reticular nucleus. Agranular area 24 receives fibers from the nucleus anteroventralis in the portion probably homologous with the nucleus anteromedialis of lower animals. Agranular area 44, agranular posterior orbital cortex, and areas 10, 32, and 12 either receive no thalamic projections or very diffuse ones. The material showed cellular evidence of intrathalamic connections.