A Motor Programming Task Activates the Prefrontal Cortex More than a Sensitivity-to-Interference Task or an Inhibitory Control Task in Older Adults

The objectives of this study were to detect age-related differences in activation of the prefrontal cortex (PFC) during the tasks of hand motions and to determine an activity-related task type activating the PFC. PFC activation during three tasks, three subtests of the Frontal Assessment Battery (FAB), was investigated in 77 healthy adults by using near-infrared spectroscopy (NIRS). The tasks were a motor programming task (FAB 3), a sensitivity-to-interference task (FAB 4) and an inhibitory control task (FAB 5). We divided participants into three age groups of Younger (20 39 years), Middle-aged (40 59 years), and Older (60 81 years), and compared relative changes in oxygenated hemoglobin concentration in the PFC during the tasks. The activation in the frontal pole (FP) and the dorsolateral prefrontal cortex (DLPFC) during a motor programming task and a sensitivity-to-interference task showed no main effects by age. The results indicated that they were not likely to be affected by age-related cognitive decline compared to an inhibitory control task. In addition, in the Older group, a motor programming task induced significantly greater activation than a sensitivity-to-interference task at eleven channels out of twelve on which we focused (p < 0.05). It was suggested that some characteristic factors included in the motor programming task such as repetition of a series of hand motions and attention to action have the potential to contribute to PFC activation in older adults. These findings provide a clue to understanding daily activities available to suppress cognitive decline of older adults by activating the PFC.