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

Abstract

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.