Age-related differences in the cortical motor network during uni-manual and bimanual coordination - an EEG study

Aging is accompanied by various neurophysiological changes that may affect cognitive and motor function. Compared to younger adults, motor performance in older adults engages more brain regions and exhibits elevated neural activity in the motor-related alpha (8-12 Hz) and beta (15-30 Hz) frequency bands of electro-encephalography (EEG) signals. To what extent these functional changes correlate with the quality of motor performance is underexplored. We recorded EEG in 19 young and 19 older adults during unimanual and bimanual visuomotor tasks with different degrees of difficulty. Older participants showed a lower quality of performance than younger adults, especially during asymmetric bimanual tasks. We analyzed source-localized activity in bilateral parietal and (pre-)motor areas to investigate, especially, the hypothesized pivotal role of left premotor cortex (PMCL) activity within the motor network during motor performance. In PMCL, beta activity was indeed significantly affected by age during bimanual performance, while alpha activity was altered in the bilateral (pre-)cuneus. When predicting error of performance via alpha and beta modulations, we found significant associations in bilateral M1 and (pre-)cuneusR during unimanual performance, while in bimanual performance, PMCL and (pre-)cuneusL were also included in the significant association. Our results confirm the importance of PMCL and (pre-)cuneusL for the performance of bimanual tasks, especially when the tasks are challenging. The age-related differences in alpha power in bilateral (pre-)cuneus and their associations with motor performance suggest that altered visuomotor integration has an important contribution to the reduction of the quality of motor performance in older adults.