Brain-stem inhibition of electrodermal (galvanic skin) activity

Spontaneous and evoked electrodermal potentials were recorded from the footpads of cats subjected to vagotomy, midmesencephalic decerebration, and serial transections of the central neuraxis from the intercollicular level to the uppermost cervical spinal segments. Eight animals were decerebellated while in the midmesencephalic condition. Electrodermal activity was profoundly depressed by midmesencephalic decerebration. Subsequent decerebellation and transections through the caudal half of the mesencephalon and the rostral third of the pons produced little alteration. However, serial transections through the middle and caudal thirds of the pons progressively enhanced electrodermal activity. Further augmentation was obtained following transection of the spinal cord. These data indicate that the brain stem contains an extensive electrodermal inhibitory system consisting of pontile and medullary components. Maximal suppression of electrodermal activity in the midmesencephalic animal requires the integrity of both components of this system. Distinguishing characteristics between the brain-stem electrodermal inhibitory system and the somatic reticular inhibitory system are discussed.