Age differences in brain activity in dorsolateral prefrontal cortex and supplementary motor areas during three different walking speed tasks

Abstract

Background: Functional Near-Infrared Spectrometry (fNIRS) is a novel neuroimaging method that can detect brain activity during functional activities. The prefrontal cortex and supplemental motor area (SMA) are active during normal and fast speed walking. However, it is unclear how age difference affects brain activity in the dorsolateral prefrontal cortex (DLPFC) and SMA when walking at different speeds. The purpose of this study was to investigate the age differences in DLPFC and SMA activation during different walking speeds.

Method: 10 younger (5F; 25 ± 8 y.o.) and 10 older adults (5F; 73 ± 6 y.o.) completed three visits in this study. Functional Near-Infrared Spectroscopy was used to detect hemodynamic changes on right and left hemispheres over the DLPFC and SMA during self-selected slow, preferred, and fast walking speeds.

Results: The results showed significantly increased DLPFC and SMA activity in older adults compared to younger adults when walking at preferred normal, fast, and slow speeds. Older adults also had a higher left DLPFC activation during preferred fast walking speed than younger adults.

Conclusion: The results suggest that there are age differences in the DLPFC and SMA activation, with older adults demonstrating increased DLPFC and SMA activity across all walk conditions compared to younger adults. This may indicate older adults require higher cognitive demand and need to recruit indirect motor pathways when changing gait speed by increasing SMA activation.

Keywords: Aging; Functional near-infrared spectroscopy; Walking speed.