Cognitive aspects of motor control: The effect of target attributes on generation of movement

Abstract

The purpose of this research was to investigate cognitive aspects involved in generation of voluntary movement. Findings from previous studies indicate cognitive processes influence fundamental movement parameters. More specifically, the researcher investigated the effect of target attributes on movement initiation and execution in seven nondemented patients with idiopathic Parkinson's disease (iPD) off medication. Persons with iPD demonstrate deficits in cognitive functions presumed to be dependent upon circuitry between the basal ganglia and the cerebral cortex. Participants employed rapid arm extension movements to explicitly identified targets (explicit target) and targets inferred from indirect cues (inferred target). Reaction time (RT) and movement time (MT) measured movement initiation and execution, respectively. Reaction time, defined as the time involved in cognitively inferring target destination and initiating movement, was partitioned into premotor RT and motor RT. Movement to the explicit versus inferred targets was kinematically equivalent; therefore, differences in RT and MT related to a difference in cognitive operations involved in generating movement to the target type. The study results indicated nondemented iPD patients were impaired in initiating and executing movement across targets containing different attributes compared to neurologically intact controls backward matched for age and education. However, both groups benefited from advanced information in initiating movement to the explicit and inferred targets. Secondly, study results indicated that nondemented iPD patients were impaired in initiating movement to a final target when shifting from a prior target. Neuropsychological measures of shifting capacity did not correlate with movement initiation to the final target in patients with iPD. Thirdly, study results indicated that program for motor execution, in terms of specifying trajectory to the explicit and inferred targets, may be impaired in patients with iPD. Findings from this research suggest the basal ganglia are involved in processing cognitively derived target attributes into plans and programs for movement. Findings may contribute to knowledge about target attributes that optimizes motor performance in persons with iPD and results in nursing interventions and rehabilitative therapies that capitalize on use of appropriate target attributes to alleviate altered movement in afflicted persons.