Influence of Dominance on Human Brain Activity During Voluntary Movement in Parkinson’s Disease

Abstract

Hand dominance is known to make a robust bias on human brain activity in a normal state. Recent studies showed that simple motor tasks performed by a non-dominant hand caused increased activation, similar to that which occurs when more complex tests are performed with a dominant hand. The influence of dominance on brain activity in Parkinon’s disease (PD) remains unclear. In the present study we made an attempt to analyse the differences between brain activity during dominant and non-dominant hand movements in PD and compare it with the control group. We used functional MRI and an event-related paradigm to study the brain activity of 16 subjects in control group and 16 patients with PD during left and right hand movements. Data analysis showed few clearly lateralized clusters of activity in major motor areas in the control group and two hemispheric activation in motor and non-motor areas in PD group during both hand movements. We also found a deficit in the activation of the primary somatosensory cortex, primary motor cortex, basal ganglia, and insula during both movements in the PD group compared to controls. At the same time we found brain activity asymmetry caused by the dominance influence in the PD group. Thus, we have shown that although motor deficit in Parkinson's disease has a greater effect on habitual movement, the influence of dominance still persists and should be taken into account in PD studies.