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Biomedical subjects

C D Zhou

Publications and source records attributed to C D Zhou.

6 recordsLinked to original sources
PubMed2001

[Application of brain state related EEG complexity measure in mental workload evaluation].

Objective. The Application of Cs to mental workload evaluation was investigated. Method. EEG of 47 male (aged 23-33) were recorded during rest or doing mental arithmetic, and changes of Cs with relation to mental arithmetic load were analyzed and compared by means of Cs analysis method. Result. Cs distribution was laterally symmetry, higher in temporal and lower in occiput. The changes of Cs over some brain areas were outstanding and stable while doing mental arithmetic: type A, 38 subjects (81%), Cs under mental arithmetic were significantly higher than Cs under rest except over prefrontal, and the most outstanding areas were post-temporal and left parieto-occipital regions; type B, 9 subjects (19%), Cs over post-temporal and parieto-occipital under rest is higher than type A, and Cs under mental arithmetic descend significantly (the most outstanding areas were right central and mid-temporal, then left frontal-central and pre-temporal). Moreover there were some possible relationship among Cs, mental arithmetic score and subjective evaluation of mental workload. Conclusion. There exists high correlation between Cs and mental arithmetic activity, and Cs could well reflect brain function state. It provide a new method and a possible way for objective evaluation of mental workload and studies of brain cognitive activities.

Adult↗
PubMed2001

[Effect of head-down bed rest on human EEG].

Objective. To study the influences of short-term simulated weightlessness on human EEG. Method. EEG of 12 male subjects (aged 18-22) was recorded, pre-HDBR (-6 degrees head down bed rest), mid-HDBR (3rd, 4th, 6th day) and post-HDBR (3rd day). Then these EEG recordings were analyzed by power spectral analysis. Result. During HDBR, peak frequency of EEG gradually slowed down (6th day, P<0.05). Alpha-band activities were enhanced (alpha1: P<0.001. Alpha2: 3rd and 6th day, P<0.05; 4th day, P<0.001) and reached maximum on the 4th day. Alpha1/alpha2 ascended (6th day, C3 and C4: p<0.02; F4, P4, T3, T4, T5: P<0.05). Theta-band activities enhanced (P<0.001), and reached maximum on the 3rd day at frontal regions, on the 4th day at parieto-occipital regions. Theta/alpha ascended obviously (6th day, P3, O1: P<0.05). Meanwhile, beta1, activities also enhanced (P<0.001), and reached maximum on the 3rd day at frontal regions. After HDBR, the index that recovered to the pre-HDBR level first was EEG peak frequency. Conclusion. HDBR caused obvious changes of EEG power spectrum characteristic. There exists a potential influence on brain function.

Adolescent↗
PubMed2000

[A study on establishing method in analysing EEG state complexity].

Objective. To establish method in analysing EEG complexity as related to brain function state (Cs) and to examine Cs under conditions of taking rest and doing mental arithmetic, to explore their regular changes. Method. EEG of 10 male subjects aged 26-30 under the conditions of taking rest and doing mental arithmetic were recorded. Cs under the two conditions and their changes related to brain function states were analyzed with a special software for Cs analysis. Result. EEG Cs under mental arithmetic changed significantly. According to these changes, the subjects were divided into two groups: Group A, 8 subjects, their EEG Cs under mental arithmetic were significantly higher than Cs under rest at all electrode sites. The most outstanding areas were temporal region and parieto-occipital region. Group B, 2 subjects, their EEG Cs under mental arithmetic were significantly lower than Cs under rest. The most outstanding areas were prefrontal region and temporal region. Conclusion. The result showed that high correlation existed between mental arithmetic and Cs. This method of analysis was useful in studying brain cognitive activities and assessing mental workload.

Adult↗
PubMed1999

Dominant frequency uncertainty analysis of EEG alpha activity in pilots with transient ischemic attacks.

Objective. To study the characteristics of EEG after transient ischemic attack and to offer reference for screening procedure of aircrew and astronaut selection. Method. The dominant frequency uncertainty of alpha band EEG in 12 pilots (males; age 30 +/- 5) with transient ischemic episodes in middle cerebral artery (MCA) territories and in 20 normal healthy pilots was analyzed with frequency-fluctuation analysis. Result. The dominant probability of the main frequency coinciding with sites affected by transient ischemic attack (TIA) in patient pilots was higher than that in healthy pilots (P<0.01), and the dominant probability ratio logarithmic index I >or= 0 in all patient pilots with normal EEG, but I<0 in all healthy pilots. It was also found that not only I >or= 0, but the second component shifted to lower frequency (8 Hz) in patients with slight focal EEG alterations, i.e. slowing of frequency. The relative entropy values (percentage) were decreased significantly in pilots with TIA as compared with healthy pilots (P<0.05). Conclusion. The dominant frequency uncertainty analysis of alpha band showed clear superiority of computerized evaluation over routine visual assessment for the diagnosis of minor cerebral ischemia. It offers not only a possibility of studying pathophysiological functional parameter, but also the reference for screening procedure in aircrew and astronaut selection.

Acceleration↗
PubMed1983

The gravitational field and brain function.

The frontal cortex is recognized as the highest adaptive control center of the human brain. The principle of the "frontalization" of human brain function offers new possibilities for brain research in space. There is evolutionary and experimental evidence indicating the validity of the principle, including it's role in nervous response to gravitational stimulation. The gravitational field is considered here as one of the more constant and comprehensive factors acting on brain evolution, which has undergone some successive crucial steps: "encephalization", "corticalization", "lateralization" and "frontalization". The dominating effects of electrical responses from the frontal cortex have been discovered 1) in experiments under gravitational stimulus; and 2) in processes potentially relating to gravitational adaptation, such as memory and learning, sensory information processing, motor programing, and brain state control. A brain research experiment during space flight is suggested to test the role of the frontal cortex in space adaptation and it's potentiality in brain control.

Acceleration↗