Respiratory responses to electrical stimulation of the basal ganglia in cats

The aim of the present study was to investigate the involvement of basal ganglia in altering respiration. The experiments were carried out on cats using the electrical stimulation techniques. The electrical stimulation of the basal ganglia caused locus-dependent changes both in the tidal volume and the rate of respiration. The most frequent effect of stimulation was hyperpnea and decrease in the tidal volume in awake, freely moving cats. An increase in the tidal volume appeared only as rebound-like aftereffect. The stimulation that caused hyperpnea in awake cats elicited smaller changes under chloralose or ketamine-induced anaesthesia, and, in certain cases, the stimulation produced apnea. After locally applied neurotoxic damage, the electrical stimulation failed to induce significant respiratory changes. It is suggested that the fast, small amplitude ventilation is, probably, produced by high excitation that shifts the respiratory rhythm generator towards the upper limits of its regulatory range. The slowing of ventilation might be produced by an inhibitory mechanism, which is able to cause even apnea under anaesthesia.