This study investigates the mechanisms underlying attentional enhancement of neural synchrony in the visual cortex, specifically in area V4, and its coupling with the frontal eye field (FEF). Using paired-recordings in two monkeys trained to attend to a stimulus in their shared receptive field, the researchers found that attention to this stimulus enhanced firing rates and gamma frequency synchrony in both areas. The coupling between FEF and V4 was initiated by FEF and appeared time-shifted by about 8-13 ms across a range of frequencies, which may optimize the impact of spikes from one area on the other. Granger causality analysis suggested that top-down inputs from FEF to V4 predominate at the onset of attention, but bottom-up inputs from V4 to FEF become more significant over time. The study also found that coupled oscillations were smaller for non-overlapping receptive fields, suggesting that these oscillations are crucial for effective communication between areas. These findings highlight the role of FEF in generating and maintaining attention-related synchrony in V4, potentially through enhanced spike timing-dependent plasticity.This study investigates the mechanisms underlying attentional enhancement of neural synchrony in the visual cortex, specifically in area V4, and its coupling with the frontal eye field (FEF). Using paired-recordings in two monkeys trained to attend to a stimulus in their shared receptive field, the researchers found that attention to this stimulus enhanced firing rates and gamma frequency synchrony in both areas. The coupling between FEF and V4 was initiated by FEF and appeared time-shifted by about 8-13 ms across a range of frequencies, which may optimize the impact of spikes from one area on the other. Granger causality analysis suggested that top-down inputs from FEF to V4 predominate at the onset of attention, but bottom-up inputs from V4 to FEF become more significant over time. The study also found that coupled oscillations were smaller for non-overlapping receptive fields, suggesting that these oscillations are crucial for effective communication between areas. These findings highlight the role of FEF in generating and maintaining attention-related synchrony in V4, potentially through enhanced spike timing-dependent plasticity.