Gamma synchronization between the medial temporal lobe and medial frontal cortex for goal-directed visual attention in humans.

Goal-directed visual attention is a fundamental cognitive function that engages multiple brain regions, yet the neural circuit mechanisms in humans remain unclear. We addressed this question by simultaneously recording neural activity from the medial temporal lobe (MTL) and medial frontal cortex (MFC) during a goal-directed visual search task. We found that gamma-band synchronization between the MTL and MFC signaled target detection. Using two additional tasks, we dissociated the neural processes underlying working memory and search decision execution, revealing distinct patterns of synchronization. Further analyses showed that dorsal anterior cingulate cortex (dACC) spike-MTL LFP synchronization encoded search dynamics and contributed to guiding behavior. Importantly, MTL-MFC synchronization disproportionately modulated neural representational geometry, highlighting its impact on information encoding. Finally, we demonstrated directional gamma influences across brain areas and cross-frequency coupling. Together, these findings illuminate the circuit-level dynamics underlying visual attention and offer insights into how the human brain selectively processes information in complex visual environments.