Research and Surveillance Section, Extremity Trauma and Amputation Center of Excellence, Defense Health Agency, Falls Church, VA, USA.
Department of Rehabilitation, Walter Reed National Military Medical Center, Bethesda, MD, USA.
Exp Brain Res. 2023 Jul;241(7):1945-1958. doi: 10.1007/s00221-023-06609-6. Epub 2023 Jun 26.
Adaptive human performance relies on the central nervous system to regulate the engagement of cognitive-motor resources as task demands vary. Despite numerous studies which employed a split-belt induced perturbation to examine biomechanical outcomes during locomotor adaptation, none concurrently examined the cerebral cortical dynamics to assess changes in mental workload. Additionally, while prior work suggests that optic flow provides critical information for walking regulation, a few studies have manipulated visual inputs during adaption to split-belt walking. This study aimed to examine the concurrent modulation of gait and Electroencephalography (EEG) cortical dynamics underlying mental workload during split-belt locomotor adaptation, with and without optic flow. Thirteen uninjured participants with minimal inherent walking asymmetries at baseline underwent adaptation, while temporal-spatial gait and EEG spectral metrics were recorded. The results revealed a reduction in step length and time asymmetry from early to late adaptation, accompanied by an elevated frontal and temporal theta power; the former being well corelated to biomechanical changes. While the absence of optic flow during adaptation did not affect temporal-spatial gait metrics, it led to an increase of theta and low-alpha power. Thus, as individuals adapt their locomotor patterns, the cognitive-motor resources underlying the encoding and consolidation processes of the procedural memory were recruited to acquire a new internal model of the perturbation. Also, when adaption occurs without optic flow, a further reduction of arousal is accompanied with an elevation of attentional engagement due to enhanced neurocognitive resources likely to maintain adaptive walking patterns.
自适应的人类表现依赖于中枢神经系统来调节认知-运动资源的参与，以适应任务需求的变化。尽管有许多研究采用分割带诱发的扰动来检查运动适应过程中的生物力学结果，但没有研究同时检查大脑皮层动力学以评估心理工作量的变化。此外，虽然先前的工作表明，光流为行走调节提供了关键信息，但只有少数研究在适应分割带行走时操纵了视觉输入。本研究旨在检查在分割带行走运动适应过程中，同时调节步态和脑电图（EEG）皮层动力学，以及有无光流。13 名无损伤且基线时固有行走不对称性最小的参与者进行了适应，同时记录了时空步态和 EEG 频谱指标。结果表明，从早期到晚期适应，步长和时间不对称性减少，同时额部和颞部θ功率升高；前者与生物力学变化密切相关。虽然适应过程中没有光流并不影响时空步态指标，但它导致θ和低α功率增加。因此，当个体适应他们的运动模式时，用于编码和巩固程序记忆的认知-运动资源被招募来获得扰动的新内部模型。此外，当适应过程中没有光流时，由于可能维持自适应行走模式的神经认知资源的增强，唤醒水平进一步降低，注意力参与度升高。
