Brain mechanism of Stroop interference effect in Chinese characters.

Event-related brain potentials were measured when 11 healthy Chinese subjects finished Chinese Characters Stroop tasks. The behavioral data showed that the Stroop task yielded a robust Stroop interference effect as indexed by longer RT for incongruent than congruent color words. Scalp ERP analysis revealed the neurophysiological substrate of the interference effect: a greater negativity in the incongruent as compared to the congruent was found between 350 and 550 ms poststimulus over midline fronto-central scalp regions. Dipole source analysis (BESA software) of the difference wave (incongruent-congruent) indicated that a generator localized in prefrontal cortex (PFC) contributed to this effect, possibly related to conflict processing and response selection. The results provided electrophysiologic evidences of the brain and cognitive mechanism of Stroop interference effect in Chinese characters and suggested that the difference between Chinese characters and English words had influence on temporal patterns of the Stroop interference effect.