40 Hz visual stimulation increases gamma-band functional connectivity between visual, parietal and frontal regions

Regular 40 Hz visual flicker increases 38–42 Hz gamma-band functional connectivity between visual and parietal regions in all 29 healthy young adults.

• Why it matters: It is unclear whether 40 Hz responses outside visual cortex reflect true inter-regional connectivity or a shared stimulus-locked signal, and whether a concurrent task alters connectivity.
• What they did: EEG was recorded in a 2×2 within-participant design (Regular 40 Hz vs Irregular 30–50 Hz; with vs without target-counting) and source-space connectivity was estimated using dWPLI.
• The result: The visual–parietal connectivity increase was frequency-specific, replicated across two source reconstruction methods and sensor space, and persisted after leakage correction and stimulus-locked component removal; the concurrent task did not modulate it.

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