ABSTRACT
This chapter describes the effects of dopamine to deep brain stimulation (DBS) in parkinsonian timing, which seem to challenge both functional anatomy and theoretical accounts of the basal ganglia involvement in timing and time representation. The dopaminergic effect as conceived by the model implies that deprivation of dopaminergic nigro-striatal innervation reduces the positive feedback via the direct path and increases the negative feedback via the indirect path. The output dopaminergic neurons originating in the substantia nigra pars compacta and projecting to the striatum, as well as the striatum itself, are thought to implement the pacemaker-accumulator system in interval timing. In animals tested with the peak-interval procedure, the integrity of the striato-nigral dopaminergic system determines the pacemaker’s speed in emitting pulses. DBS in the subthalamic nucleus of dopamine-depleted Parkinson’s disease patients eliminates the retrieval, but not the encoding distortion.
