FRONTOPARIETAL CONTROL OF ELECTRODERMAL ACTIVITY IN THE CAT

The aim of this work was to investigate the direct involvement of the fronto-parietal cortex in the control of spinal autonomic centers elic iting electrodermal activity (EDA). This autonomic response, linked wi th the activity of sweat glands, was recorded as skin potential respon ses (SPRs) from forepaws in the cat. Animals were paralyzed by gallami ne and SPRs were obtained under halothane anaesthesia. For each animal , a transection of the medulla sparing only pyramidal tracts was carri ed out. SPRs were elicited by direct electrical Stimulation of pericru ciate and posterior-parietal cortical areas before and after such a tr ansection. Results showed that in intact preparations, stimulation of the pericruciate cortex evoked SPRs Bt lower thresholds than the poste rior parietal cortex. After the bulbar transection, only the stimulati on of pericruciate areas still elicited SPRs at low intensities. Resul ts are interpreted as indicating that fronto-parietal control of EDA i s probably mediated by a double descending system: one involving corti coreticulospinal pathways and a direct corticospinal one. We hypothesi zed that the somatic motor cortex initiates descending programs to aut onomic centers at bulbar and spinal levels, and that these centers are involved in autonomic adjustments to somatomotor movements.