Author: Zhang Wenbin 1//Zhen Rongrong 1//Zhang Benkun 1//Yu Weilin 1//Shen Xueyong 2
Qigong Research Institute, Shanghai Academy of Traditional Chinese Medicine, Shanghai, China  //Dept of Acupuncture & Moxabustion, Shanghai College of TCM, China 
Conference/Journal: 2nd Int Conf on Qigong
Date published: 1989
Other: Pages: 10 , Word Count: 344
The purpose of this work was to investigate functional state of cerebral cortex during qigong meditation with flash visual evoked potentials (F-VEPs).
The F-VEPs recorded from occipital scalp were studied in 4 groups of adults aged 27-29 years. The 1st group included 14 persons who had exercised themselves in Neiyang Gong for 0.5-5.5 years, averaged 2.3 years. The second group was composed of 12 subjects who had practised Neiyang Gong for only 0.5-3 months with a mean of 1.9 months. Eleven qigong practitioners of different schools, of whom 8 were professional men, constituted the third group. Eleven subjects who had never practised qigong before made up the fourth group and served as controls. The flash source was a xenon lamp situated 50 cm from the subject's eyes. Eight runs of advanced VEP recordings were taken during each experimental session. Of them 2 runs before, 2 runs after and 4 runs during qigong meditation were taken respectively.
The averaged flash response recorded in our laboratory appeared to be a complicated waveform consistent of several negative and positive deflections, designated as N80--115-N150-P200-N280. In the first group, the peak-peak amplitudes of N80-P115-N150 increased from 14.7±5.7 to 16.7±7.4 µv (p<0.05) and those of N150-P200-N280 FROM 19.9±6.9 to 25.0±10.0 µv (p <0.01) during qigong meditation. The results of the third group on the contrary, i.e., N80-P115-N150 amplitude decreased by 3.6±5.5 µv (0.1>p > 0.05) and N150-P200-N280 decreased by 3.8±µ3.8 uv (p<O.05 ) in 10 practitioners except one whose VEP amplitudes increased markedly as he fell into meditation. No such significant changes were found in the second group and controls. The VEP latencies seemed to be relatively steady in nearly all cases throughout the experiment.
The results were discussed and it was shown that the VEP amplitude changes in Neiyang Gong practicing group and qigong practitioners were not due to dark adaptation, pupil size variation, mainly by the functional alteration of cerebral cortex during qigong meditation .It is presumed that qigong meditation may have facilitative or inhibitory effects on visual cortex according to the qigong methods practised by different individuals.