How patients with Parkinson's disease retrieve and manage cognitive event knowledge

Several studies have pointed out that basal ganglia are involved in adaptiv e control of action at both motor and cognitive level. This study aimed to investigate how basal ganglia retrieve and manage script event knowledge re quired in planning behavior. Script event knowledge was investigated in pat ients with Parkinson's Disease using three kinds of activity that differed in familiarity. Unlike patients with prefrontal lesions, patients with Park inson's Disease were able to order events in a typical sequence and obeyed the boundaries and hierarchies between events. In contrast, patients with P arkinson's Disease were impaired in evaluating how important each script ev ent was within the context of goal-oriented planning activity. Our findings indicate that the prefrontal cortex and the basal ganglia are differential ly involved in planning. The role of the basal ganglia might consist in pro viding a feedback about the goodness of each action while building up meani ngful sequences of events during learning.