TY - JOUR
T1 - Treading on the unknown increases prefrontal activity
T2 - A pilot fNIRS study
AU - Koren, Yogev
AU - Parmet, Yisrael
AU - Bar-Haim, Simona
N1 - Funding Information:
We wish to thank Professor Stephane Perrey and Dr. Gregoire Vergotte (Montpelier University, EroMov, France) for sharing their knowledge and experience, as well as assisting in the NIRS data processing. This study was supported by The Research Fund on Insurance Matters Affiliated with the Israel Insurance Association ( 58-029123-5 ). The Helmsley Charitable Trust through the Agricultural, Biological and Cognitive Robotics Initiative and by the Marcus Endowment Fund and Recanati school foundation at Ben-Gurion university. Sponsors were not involved in this study.
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/3/1
Y1 - 2019/3/1
N2 - Background: Complex walking conditions (e.g. dual tasking) have been associated with increased prefrontal (PFC) activity. However, most paradigms include a predictable environment, specifically, a predictable walking terrain. In the present study we investigate PFC activity under an unusual walking condition where each foot placement was on unexpected terrain, thus causing a mismatch between visuospatial perception and lower-extremity proprioception. Research objective: To assess whether PFC activity increases under unstable unpredictable conditions compared to unstable but predictable conditions. Methods: This was a prospective study involving twenty healthy adults. Participants walked in two conditions: unstable but predictable, and unstable and unpredictable. To assess walking stability, both stride-time (ST) and stride-time variability (CV) were measured. To assess PFC activity, two wireless near-infrared spectroscopy devices were used. The group hemodynamic response (GHR) was calculated for each condition. For statistical analysis, a linear-mixed-effects model was used. Results: Walking with unpredictable perturbations did not change the ST (t = 0.51, p = 0.61) but significantly increased the parameter CV (t = 11.74, p < 0.001). The GHR of both conditions indicated brief per-initiation PFC activity that was similar across conditions. However, when GHRs were calculated relative to normal walking (i.e., the participants’ own shoes), continuous activity was evident. Compared to the predictable condition, the unpredictable condition significantly increased this activity during steady-state walking (t = 2.13, p = 0.033). Significance: Observations from the present study suggest that at least two neural components are present in the measured signal—a brief one, occurring per-initiation, and a continuous one, sensitive to the predictability of the terrain. The second component was accompanied by a decrease in walking stability. These results may contribute to our understanding of the control mechanism underlying gait and future planning of rehabilitation protocols.
AB - Background: Complex walking conditions (e.g. dual tasking) have been associated with increased prefrontal (PFC) activity. However, most paradigms include a predictable environment, specifically, a predictable walking terrain. In the present study we investigate PFC activity under an unusual walking condition where each foot placement was on unexpected terrain, thus causing a mismatch between visuospatial perception and lower-extremity proprioception. Research objective: To assess whether PFC activity increases under unstable unpredictable conditions compared to unstable but predictable conditions. Methods: This was a prospective study involving twenty healthy adults. Participants walked in two conditions: unstable but predictable, and unstable and unpredictable. To assess walking stability, both stride-time (ST) and stride-time variability (CV) were measured. To assess PFC activity, two wireless near-infrared spectroscopy devices were used. The group hemodynamic response (GHR) was calculated for each condition. For statistical analysis, a linear-mixed-effects model was used. Results: Walking with unpredictable perturbations did not change the ST (t = 0.51, p = 0.61) but significantly increased the parameter CV (t = 11.74, p < 0.001). The GHR of both conditions indicated brief per-initiation PFC activity that was similar across conditions. However, when GHRs were calculated relative to normal walking (i.e., the participants’ own shoes), continuous activity was evident. Compared to the predictable condition, the unpredictable condition significantly increased this activity during steady-state walking (t = 2.13, p = 0.033). Significance: Observations from the present study suggest that at least two neural components are present in the measured signal—a brief one, occurring per-initiation, and a continuous one, sensitive to the predictability of the terrain. The second component was accompanied by a decrease in walking stability. These results may contribute to our understanding of the control mechanism underlying gait and future planning of rehabilitation protocols.
KW - Prefrontal-cortex
KW - Re-Step
KW - Uneven-terrain
KW - Walking
KW - fNIRS
UR - http://www.scopus.com/inward/record.url?scp=85060499412&partnerID=8YFLogxK
U2 - 10.1016/j.gaitpost.2019.01.026
DO - 10.1016/j.gaitpost.2019.01.026
M3 - Article
C2 - 30690327
AN - SCOPUS:85060499412
SN - 0966-6362
VL - 69
SP - 96
EP - 100
JO - Gait and Posture
JF - Gait and Posture
ER -