The function of dopaminergic neural signal transmission in auditory pulse perception: evidence from dopaminergic treatment in Parkinson's patients.

Auditory pulse perception, which is the perception of relatively salient and regularly appearing events in an acoustic sequence, is a necessary function in humans and has been suggested to rely on basal ganglia function. Our study investigated the effect dopamine depletion has on the auditory pulse perception in Parkinson's disease (PD). We examined PD patients and healthy seniors in this study, and all participants performed a pulse perception task and a motor control task. The pulse perception task consisted of a two alternative forced choice task in which subjects had to identify stimuli as metrical or non-metrical. We tested PD patients before and after the administration of l-3,4-dihydroxyphenylalanin (l-DOPA). The healthy control group performed the same tasks twice. PD patients that were dopamine depleted performed the pulse perception task equally well and as fast as did the healthy control group. However, after the administration of l-DOPA, PD patients performed the pulse perception task significantly faster than they did before the pharmacological intervention, which showed that pulse perception can be modulated by dopaminergic stimulation. These findings indicate that pulse perception relies on dopaminergic mechanisms but is not affected by dopamine depletion in the early stages of PD.