Mesencephalic and bulbar reticular control of skin potential responses in kittens.

Reticular command of Skin Potential Responses (SPRs) was investigated in 30 kittens between 1 and 30 days of age which had been acutely implanted under chloralose anaesthesia (40 mg/kg). The results show that (a) SPRs can be elicited through electrical stimulation of the mesencephalic reticular formation (MRF) in kittens as early as a few hours after birth. As in the adult cat, these SPRs consist of a monophasic negative wave. Up until the age of 10 days SPRs recorded from the forepaws are significantly larger than those from the hindpaws. There is not difference in amplitude between ipsilateral and contralateral responses, relative to the stimulation site. (b) The first of a pair of MRF stimuli is followed by a subnormal period of 50 s, during which a second MRF stimulus of the same intensity evokes SPR of lower amplitude. (c) Stimulation of certain parts of the bulbar reticular formation (BRF) inhibits the SPRs evoked through MRF stimulation. The average percentage of inhibition was 65% in 10 kittens aged from 1 to 15 days. These results suggest that the reticular centers which control electrodermal activity are functional at birth and that certain characteristics of electrodermal activity are subject to post-natal maturation.