Neural markers of visual working memory during an upper extremity movement-coupled task: a mobile brain-body imaging (MOBI) study.

Optimal goal-directed behavior in everyday life involves the appropriate coupling of cognition and movement. In this study we employed a mobile brain-body imaging (MoBI) system that integrated time-synchronized high-density electroencephalography with 3-dimensional motion capture during a touchscreen visual working memory task requiring dynamic upper extremity reach responses. Using this framework we examined how increasing memory load (i.e. from 1-disc to 4-discs) influences behavior and scalp-recorded neural activity when cognitive and motor processes are coupled within a single task and whether these effects are modulated by handedness. Increasing memory load reliably degraded working memory task performance and slowed motor preparation, while core movement execution measures remained largely preserved. Regarding electroencephalography data, parieto-occipital activity increased with load during both the early visual-evoked N1 and the delay period. However, load-related modulation reached a plateau at the 3-disc condition during the delay period only. Posterior-frontal engagement also strengthened as load increased, consistent with demands on attentional control, memory maintenance, and sensorimotor planning. Brain-behavior associations were most robust at a moderate level (2-disc), where contralateral delay activity correlated with both cognitive and motor performance measures. Finally, although handedness exerted selective behavioral effects, it did not modulate load-related parieto-occipital neural activity. Together, these findings demonstrate that a multimodal MoBI approach captures integrated cognitive-motor dynamics during working memory-guided actions, providing a more comprehensive characterization of behavior and underlying neural signatures than either modality alone. This framework offers a translational approach for studying cognitive-motor interactions and their potential disruption in neurological conditions such as Parkinsons disease.