Maintaining task performance levels under cognitive load while walking requires widespread reallocation of neural resources: A Mobile Brain-Body Imaging (MoBI) study.

The neural underpinnings of increasing cognitive load during walking, despite being ubiquitous in everyday life, is still not fully understood. This study elucidates the neural mechanisms underlying increased cognitive load while walking, by employing 2 versions of a Go/NoGo response inhibition task, namely the 1-back Go/NoGo task and the more cognitively demanding 2-back Go/NoGo task, during sitting or walking on a treadmill. By using the Mobile Brain/Body Imaging (MoBI) modality, electroencephalographic (EEG) activity, three-dimensional (3D) gait kinematics and task-related behavioral responses were collected from 34 young adults for the 1-back Go/NoGo task and 34 young adults for the 2-back Go/NoGo task. Interestingly, increasing cognitive-inhibitory load from 1-back to 2-back Go/NoGo during walking was not associated with any detectable costs in response accuracy, response speed, or gait consistency; however, it came with attenuations in walking-related EEG amplitude changes during both successful inhibitions (correct rejections) and successful executions (hits) of the Go motor response. During correct rejections, such attenuations were detected over frontal regions, during latencies related to sensory gain control, conflict monitoring and working memory storage and processing. During hits, attenuations were found over left-parietal regions, during latencies related to orienting attention to and selecting the Go motor plan, as well as over central regions, during latencies linked to executing the Go motor response. The pattern of attenuation in walking-related EEG amplitude changes, manifested by the 2-back Go/NoGo group, is thought to reflect more effortful recalibration of the above neural processes, a mechanism which might be a key driver of performance maintenance in the face of increased cognitive demands while walking. Overall, the present findings shed light on the extent of the neurocognitive capacity of young adults, thus revealing the employed methodology as promising for better understanding how factors such as aging or neurological disorders could impinge on this capacity.