Programming and execution of sequential movements in Parkinson's disease.

In separate blocks of a simple reaction time (RT) task, eight Parkinsonian and eight control subjects executed finger press sequences with one (index finger), two (index finger-ring) or three (index finger-ring-middle) components. Programming was inferred from the increase latency to initiate the first component as a function of the length of the entire sequence; and from the systematic decrease in inter-response latencies for the second and third components. Overall RT was slower in the Parkinsonians but the programming effects were comparable in the two groups. Intact basal ganglia function appears not to be necessary for programming sequential finger movements, or retrieving subprograms for execution.