RESPONSES ELICITED BY STIMULATION OF THE MESENCEPHALIC TEGMENTUM IN THE CAT

Abstract

Experiments have shown that in the cat, the rostral portion of the mesencephalic tegmentum and its continuation into the hypothalamus are involved in the act of walking. In the absence of the cerebral cortex and thalamus, a number of reflex patterns are present which would necessitate descending pathways other than the corticospinal tracts, i. e., tracts of an extrapyramidal nature. There are a number of such pathways, any one of which may be essential for such descending conduction.¹ There have been several observations which show that stimulation of the mesencephalic tegmentum in the region of the red nucleus in the monkey and the cat produces ipsolateral flexion and contralateral extension in the fore limbs and varying responses in the hind limbs. This may represent one of the components of walking and other reflex activities of the mesencephalic tegmentum, and it was with the purpose of a further analysis of