MULTIMODAL FUNCTIONAL NEAR-INFRARED SPECTROSCOPY AND EYE-TRACKING ASSESSMENT DURING COGNITIVE AND EMOTIONAL TASKS: PILOT EVIDENCE FOR INTEGRATED MEASUREMENT OF BRAIN ACTIVATION AND BEHAVIOR

Understanding cognition and emotion demands measurement modalities that capture both brain activity and behavioral dynamics. Functional near-infrared spectroscopy (fNIRS) and eye-tracking (ET) each provide distinct information about neural and attentional processes, yet most prior work employs ET alone, limiting interpretation of underlying neural activation. We developed an experimental paradigm combining fNIRS and ET simultaneously during three task paradigms designed to probe attention/inhibition, working memory, and emotion processing. Fifty-one adult participants completed randomized blocks of a pro/anti-saccade task assessing attentional control and inhibition, an N-back task evaluating working memory load, and a face-emotion recognition task measuring emotion discrimination. All tasks were performed without manual responses, relying exclusively on gaze behavior to minimize motor confounds and enable seamless integration of ET and fNIRS signals. fNIRS channels were positioned over prefrontal and frontoparietal regions implicated in executive function and emotion regulation, while ET provided pupil dynamics and gaze metrics synchronous with hemodynamic responses. Behavioral accuracy for the pro/anti-saccade task ranged between 81–83%, N-back performance showed expected load-dependent decreases (0-back: 90–95%; 2-back: 52%), and face-emotion recognition accuracy varied by difficulty (easy: 79%; normal: 80–81%; hard: 74–75%). Preliminary fNIRS data indicate distinct patterns of activation corresponding to task demands, with increased prefrontal oxygenation during higher working memory load and emotion processing. These pilot results demonstrate the feasibility of integrated fNIRS-ET measurement and suggest enhanced sensitivity for characterizing cognitive and emotional processes. Future work will refine task design and extend this paradigm to older adults with depressive symptoms to explore clinical applications.