Regional difference in prefrontal oxygenation before and during overground walking in humans: a wearable multichannel NIRS study

Abstract

Using wireless multi-channel near-infrared spectroscopy, regional difference in cortical activity over the prefrontal cortex (PFC) was examined prior to and during overground walking, and in response to changes in speed and cognitive demand. Oxygenated-hemoglobin concentration (Oxy-Hb) as index of cortical activity in ventrolateral PFC (VLPFC), dorsolateral PFC (DLPFC), and frontopolar cortex (FPC) was measured in 14 subjects, while heart rate was measured as estimation of exercise intensity in 6 subjects. The impact of mental imagery on prefrontal Oxy-Hb was also explored. On both sides, Oxy-Hb in VLPFC, DLPFC, and lateral FPC was increased prior to the onset of normal speed walking, whereas Oxy-Hb in medial FPC did not respond prior to walking onset. During the walking, Oxy-Hb further increased in bilateral VLPFC, whereas Oxy-Hb was decreased in DLPFC and lateral and medial FPC. Increasing walking speed did not alter the increase in Oxy-Hb in VLPFC but counteracted the decrease in Oxy-Hb in DLPFC (but not in lateral and medial FPC). Treadmill running evoked a greater Oxy-Hb increase in DLPFC (n = 5 subjects). Furthermore, increasing cognitive demand during walking, by deprivation of visual feedback, counteracted the decrease in Oxy-Hb in DLPFC and lateral and medial FPC, but it did not affect the increase in Oxy-Hb in VLPFC. Taken together, the profound and localized Oxy-Hb increase is a unique response for the VLPFC. The regional heterogeneity of the prefrontal Oxy-Hb responses to natural overground walking was accentuated by increasing walking speed or cognitive demand, suggesting functional distinction within the PFC.

Dissociated coupling between cerebral oxygen metabolism and perfusion in the prefrontal cortex during exercise: a NIRS study

“…To evaluate the time course of variables, bins of 15-s data were sampled every 1 min. For the baseline data, we applied averaged data of 30 s, avoiding a duration of 30 s immediately before the start of exercise as NIRS signals in the PFC increase before the initiation of voluntary leg cycling ( Matsukawa et al, 2015 ; Asahara et al, 2022 ) according to the central command ( Nowak et al, 1999 ).…”

Wearable, high-density fNIRS and diffuse optical tomography technologies: a perspective

“…Wearable fNIRS has also been used to evaluate expertise and the effect of feedback in laparoscopy procedures, 11 , 24 deception, 25 stress processing during sleep, 26 and walking. 12 , 27 A range of studies have also sought to employ wearable fNIRS devices in the study of infants during naturalistic interactions and play. 28 …”

“…Wearable fNIRS has also been used to evaluate expertise and the effect of feedback in laparoscopy procedures, 11,24 deception, 25 stress processing during sleep, 26 and walking. 12,27 A range of studies have also sought to employ wearable fNIRS devices in the study of infants during naturalistic interactions and play. 28 As wearable fNIRS systems have developed at pace over the last 10 to 15 years, a parallel research effort has been focussed on increasing the spatial resolution and anatomical specificity of fNIRS and DOT approaches through the use of HD optode arrays.…”