Diencephalic distributions of ascending reticular systems

The ascending projections of the brain stem reticular formation were mapped using electrophysiological methods and short latency responses were found in the internal capsule and in the head of the caudate nucleus in the telencephalon.

Abstract

The ascending projections of the brain stem reticular formation were mapped using electrophysiological methods. Low voltage single pulse electrical stimulation of the ponto-mesencephalic reticular core produced short latency unit discharges and evoked responses in two discrete diencephalic regions: the intralaminar-ventral anterior nucleus system and the subthalamus. In the telencephalon, short latency responses were found in the internal capsule and in the head of the caudate nucleus. These results are compared with earlier physiological and anatomical studies on the distribution of ascending reticular projections and the relationship of the findings to the problem of reticular projections to cortical association areas is discussed.