Journal - Journal of Neuroscience

Abstract :

Although functional imaging studies have frequently examinedage-related changes in neural recruitment during cognitive tasks,much less is known about such changes during motor performance.In the present study, we used functional magnetic resonanceimaging to investigate age-related changes in cyclical handand/or foot movements across different degrees of complexity.Right-handed volunteers (11 young, 10 old) were scanned whileperforming isolated flexion-extension movements of the rightwrist and foot as well as their coordination, according to the"easy" isodirectional and "difficult" nonisodirectional mode.Findings revealed activation of a typical motor network in bothage groups, but several additional brain areas were involvedin the elderly. Regardless of the performed motor task, theelderly exhibited additional activation in areas involved insensory processing and integration, such as contralateral anteriorinsula, frontal operculum, superior temporal gyrus, supramarginalgyrus, secondary somatosensory area, and ipsilateral precuneus.Age-related activation differences during coordination of bothsegments were additionally observed in areas reflecting increasedcognitive monitoring of motor performance, such as the pre-supplementarymotor area, pre-dorsal premotor area, rostral cingulate, andprefrontal cortex. In the most complex coordination task, theelderly exhibited additional activation in anterior rostralcingulate and dorsolateral prefrontal cortex, known to be involvedin suppression of prepotent response tendencies and inhibitorycognitive control. Overall, these findings are indicative ofan age-related shift along the continuum from automatic to morecontrolled processing of movement. This increased cognitivemonitoring of movement refers to enhanced attentional deployment,more pronounced processing of sensory information, and intersensoryintegration.