[Impulse reactions of cortico-spinal neurons to stimulation of the lateral hypothalamus].

In anesthetized cats, evoked responses of pyramidal tract (PT) cells to lateral hypothalamus (LH) stimulation were studied in pericruciate cortex. The PT cells responded to hypothalamic stimulation with latencies ranging from 1.6 to 52.5 msec and were situated between 0.75 and 2.5 mm below the pial surface. Orthodromic spikes of PT neurons occurred more readily during stimulation of caudal part of the LH. PT neurons activated by the LH stimulation were also tested with electro-skin stimulation of limbs: 75% of the neurons responded to stimulation of several limbs and had large bilateral receptive fields, 15%--to one contralateral limb stimulation and had small contralateral receptive fields. The time of involvement of PT cells in the responses to hypothalamic or somesthetic signal had no correlation with the type of these neurons according to their axonal conduction velocity.