Somatomotor and cardiorespiratory responses to basal ganglia stimulation in cats.

The electrical stimulation of the neural elements within the basal ganglia circuitry caused characteristic somatomotor activities and changes in arterial blood pressure (BP), heart rate (HR), and respiratory rate (RR) in conscious, unrestrained cats. A highly constant pattern of responses was elicited by stimulating repeatedly at the same locus, but significant differences occurred among responses obtained from identified parts of the basal ganglia. Stimulation in the putamen evoked tachypnoe, but no remarkable change in BP and HR. Stimulation in the caudate nucleus produced either tachypnoe or respiratory arrest accompanied by a slight change in BP and HR. Stimulation within the medial dorsal nucleus of the thalamus and the substantia nigra caused increase in BP, HR, and RR of different magnitude. The increase in BP failed to appear under the effect of alpha-adrenergic blockade. The effects of procaine, injected through the arterial cannula, did not interfere with the electrically elicited responses. All the cardiorespiratory responses to basal ganglia stimulation diminished or did not appear in deeply anaesthetised animals. We conclude that besides its involvement in motor processing, the basal ganglia circuitry exerts an influence on the central cardiorespiratory mechanisms.