Biomedical subjects

Dong-xu Han

Publications and source records attributed to Dong-xu Han.

3 recordsLinked to original sources

PubMed2005

[Changes of EEG frequency-fluctuation characteristics during visual workloads].

OBJECTIVE: To observe the changes of alpha-band frequency-fluctuation characteristics of EEG under visual task. METHOD: Nineteen healthy right-handed male volunteers served as subjects, aged 24-32. EEG were recorded during rest (eyes-closed and eyes-open) and visual task, then analyzed using EEG frequency-fluctuation analysis system. RESULT: From eyes-closed to eyes-open, then to visual task state, the probability distribution characteristics of alpha-band frequency-fluctuation were significantly changed. The probability of 9 Hz and 10 Hz dominance decreased significantly, while the probability of 8 Hz and 11-13 Hz dominance increased significantly. The single component occupying absolute dominance was gradually transformed into the competition between these various components, and the lower frequency component in the front brain-areas gradually occupied dominance; meanwhile, the dominant fluctuation entropy increase significantly, the dominant fluctuation energy decreased significantly, and these processes showed obviously the brain-area related characteristics. CONCLUSION: These changes of alpha-band frequency-fluctuation characteristics reflect the further enhancement of brain activities in the areas related to visual task. This method may be helpful in the study of visual workloads.

Adult↗

PubMed2004

[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.

Adult↗

PubMed2002

[Effects of simulated weightlessness on EEG frequency fluctuation characteristics].

Objective. To develop a method of EEG monitoring under special environment, which is of value for astronauts selection and training. Method. Weightlessness was simulated by means of -6 degrees head down bed rest (HDBR). Rest EEG was recorded in 12 male subjects (aged 18-22) with eyes-closed and then analyzed by means of EEG frequency-fluctuation analysis system. Result. Before HDBR, the dominant order at parietal and occiput was 10, 9, 11 Hz; At frontal and temporal regions 9 Hz competed with 10 Hz for the main dominant component, while the third was 7 Hz. During HDBR, reversible changes of position and interrelation between 7, 8, 9, 10, 11 and 12 Hz appeared, and the frequency components and their regions involved spread gradually. The probability of 7 Hz and 8 Hz dominance increased, while 10 Hz and 11 Hz dominance decreased. At parietal, occiput and post-temporal regions, 9 Hz competed with 10 Hz for the main dominant component, the third was 7 Hz. At frontal and pre-temporal regions, 9 Hz occupied the main dominant position, while the second was 7 Hz (at right-frontal regions, it even occupied the main dominant position), the third was 10 Hz. Conclusion. Simulated weightlessness cause change of EEG dominant-frequency fluctuation competitive structure significantly. Brain adaptation function decrease, and headache can be easily induced. There exists a potential influence on brain function.

Adolescent↗