Preliminary exploration of the neural mechanisms of the qigong state based on the method of auditory evoked responses

This paper is intended to approach the neural mechanisms of the qigong state from three levels: the cortex, the brainstem, and the peripheral.

Method: 38 subjects with normal audition (32 male and 6 females), aged 21-50 years, and 2-30 years for qigong practice were chosen. Evoked potential was averaged by using an Evoked Response Recorder (model MEB-5100). Middle Latency Response (MLR), Auditory Brainstem Response (ABER), Electrocochleargram (EcochG) and post-auricle potential (PAP) were measured before the qigong exercise, then the subject was ordered to enter the qigong state. The response was done 10 min. later. Then the subjects were called out and recorded 30 min. after the exercise.

Results: The results showed that there were significant difference between the control period (before the qigong exercise) and the qigong state in measurements. (I) The waves of the MLR were inhibited, during the qigong state, i. e. Wave Po decreased by 31. 43%; Na decreased by 72.1% (P<O.Ol); Pa decreased by 54.72% (P<0.05) . (2) The amplitudes of the ABR, on the other hand, were facilitated except Wave Vll was inhibited, i.e. Wave I increased by 63.14 % (P<O.05); Wave 11 increased by 71.35 % (P<O.001 ); Wave 111 increased by 67.59% (P<O.01); Wave IV increased by 138.12% (P<O.001); Wave V increased by 91.93% (P<O.OO1); Wave Vl increased by 11.65%, but Wave Vll decreased by 4.47%. (3) The amplitudes of the EcochG were increased. i.e. Wave SP increased by 51.93% (P<O.Ol); Nl increased by 51.3% (P<O.001); N2 increased by 50.7% (P<O.05); N3 increased by 110.74% (P<O.05) . (4) The amplitudes of PAP were increased too, i.e. Wave Nl increased by 43.72% (P<O.05); P2 increased by 313.86% (P<O.001) and Wave N2 increased by 223.16% (P<O.01).

Discussion: The decrease of the amplitudes of MLR showed the activities of the temporal acustice cortex and the nuclei polysensory thalamus were inhibited by the qigong state. The brainstem is the Center of adjustment of the internal organ activities. The ABR potential change reflected the facilitation from the acustical nerve to the medulla oblongata. midbrain and interbrain, but the part near the acustica cortex was inhibited. This supported MLR results. The increase of the EcochG explained the excitability increase of the basilar membrane of the cochlear and the increase of Nl, N2 and N3 showed the number of the synchronous neuron of the acustic nerve was increased during the qigong state. It supported the result of ABR. PAP belongs to the muscular electric response that was evoked by the sound stimuli. Increase of PAB showed the excitability of the facial and the middle ear muscule is increased too during the qigong state. It may result from the brain stem facilitation because the centers of its reflex arc are situated in the brainstem. To sum up, the results suggest that the cerebral cortex and the hypothalamus were inhibited, while the facilitation occurred from the interbrain to the peripheral nerves and receptors during the qigong state. These provide a basis for further expounding the theory that 'when the internal organs are active the brain is quiescent' during the qigong state.