[Influence of target-tone recognition task on alpha-band frequency fluctuation characteristics in EEG].

OBJECTIVE: To study the influences of target-tone recognition task on dominant-frequency fluctuation structure of EEG. METHOD: The subjects were 21 healthy right-handed male volunteers aged 25-35 years. EEG were recorded with eyes-closed during rest or discriminating target-tone, and analyzed by means of EEG frequency-fluctuation analysis system. RESULT: Under the workload of discriminating target-tone, the main dominant components of alpha-band frequency-fluctuation of EEG speeded up. The probability of 9-10 Hz dominance decreased significantly, while the probability of 11-13 Hz dominance increased significantly. The correlation between these dominant components in dominant-frequency fluctuation competitive structure of EEG changed. Meanwhile, the afore-mentioned changes have something to do with individual EEG at rest. Around the peak frequency of EEG at rest, the dominant probability of higher frequency components increased obviously, but the dominant probability of lower frequency components decreased obviously. CONCLUSION: During the task, these significant changes of dominant-frequency fluctuation competitive structure in EEG might reflect the enhancement of brain activities related to workload. So the method of EEG frequency-fluctuation analysis may be helpful in assessing mental workload.