Effects of rhythmic visual cues on cortical activation and functional connectivity features during stepping: an fNIRS study

Front Hum Neurosci. 2024 Feb 12:18:1337504. doi: 10.3389/fnhum.2024.1337504. eCollection 2024.

Abstract

Introduction: Rhythmic visual cues (RVCs) may influence gait initiation by modulating cognition resources. However, it is unknown how RVCs modulate cognitive resources allocation during gait movements. This study focused on investigating the effects of RVCs on cortical hemodynamic response features during stepping to evaluate the changes of cognitive resources.

Methods: We recorded cerebral hemoglobin concentration changes of 14 channels in 17 healthy subjects using functional near-infrared spectroscopy (fNIRS) during stepping tasks under exposure to RVCs and non-rhythmic visual cues (NRVCs). We reported mean oxygenated hemoglobin (HbO) concentration changes, β-values, and functional connectivity (FC) between channels.

Results: The results showed that, the RVC conditions revealed lower HbO responses compared to the NRVC conditions during the preparation and early stepping. Correspondingly, the β-values reflected that RVCs elicited lower hemodynamic responses than NRVCs, and there was a decreasing trend in stimulus-evoked cortical activation as the task progressed. However, the FC between channels were stronger under RVCs than under NRVCs during the stepping progress, and there were more significant differences in FC during the early stepping.

Discussion: In conclusion, there were lower cognitive demand and stronger FC under RVC conditions than NRVC conditions, which indicated higher efficiency of cognitive resources allocation during stepping tasks. This study may provide a new insight for further understanding the mechanism on how RVCs alleviate freezing of gait.

Keywords: cortical activity; functional connectivity; functional near-infrared spectroscopy; rhythmic visual cues; stepping.

Grants and funding

The authors declare financial support was received for the research, authorship, and/or publication of this article. This research was supported by the National Key R&D Program of China (2022YFC3601701), Director Fund of Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences (2021SZKY0205), Key R&D Plan Project in Zhejiang Province (2023C03168), Natural Science Foundation of Zhejiang Province (LQ23C090005), Natural Science Foundation of Ningbo (2022J042), Ningbo Municipal Science and Technology Innovation 2025 Major Project (2020Z082), and the Ningbo Leading Medical and Health Discipline (2022-B12).