Frontal dissociations: evidence from Parkinson's disease

Abstract Control subjects and patients with Parkinson's disease were tested on three tasks that have often been held to implicate functions of frontal cortex. The tasks were verbal fluency, continuous series, and the Stroop test. In the patient group, there was no significant correlation between performance on verbal fluency and continuous series, or between verbal fluency and the Stroop test. The results are interpreted in terms of the fractionation of the Supervisory Attentional System.