Wackermann Jiri, Pütz Peter, Büchi Simone, Strauch Inge, Lehmann Dietrich
Department of Empirical and Analytical Psychophysics, Institute for Frontier Areas of Psychology, i Br, Freiburg, Germany.
Int J Psychophysiol. 2002 Nov;46(2):123-46. doi: 10.1016/s0167-8760(02)00070-3.
Manifestations of experimentally induced altered states of consciousness in the brain's electrical activity as well as in subjective experience were explored via the hypnagogic state at sleep onset, and the state induced by exposure to an unstructured perceptual field (ganzfeld). Twelve female paid volunteers participated in sessions involving sleep onset, ganzfeld, and eyes-closed relaxed waking, and were repeatedly prompted for recall of their momentary mentation, according to a predefined schedule. Nineteen channel EEG, two channels EOG and EMG were recorded simultaneously. The mentation reports were followed by the subjects' ratings of their experience on a number of ordinal scales. Two-hundred and forty-one mentation reports were collected. EEG epochs immediately preceding the mentation reports were FFT-analysed and the spectra compared between states. The ganzfeld EEG spectrum, showing no signs of decreased vigilance, was very similar to the EEG spectrum of waking states, even showed a minor acceleration of alpha activity. The subjective experience data were reduced to four principal components: Factor I represented the subjective vigilance dimension, as confirmed by correlations with EEG spectral indices. Only Factor IV, the 'absorption' dimension, differentiated between the ganzfeld state (more absorption) and other states. In waking states and in ganzfeld, the subjects estimated elapsed time periods significantly shorter than in states at sleep onset. The results did not support the assumption of a hypnagogic nature of the ganzfeld imagery. Dream-like imagery can occur in various global functional states of the brain; hypnagogic and ganzfeld-induced states should be conceived as special cases of a broader class of 'hypnagoid' phenomena.
通过睡眠开始时的入睡幻觉状态以及暴露于无结构感知场（全视野）所诱发的状态，探索了实验诱导的意识改变状态在大脑电活动以及主观体验方面的表现。12名女性有偿志愿者参与了涉及睡眠开始、全视野和闭眼放松清醒的实验环节，并按照预先设定的时间表多次被提示回忆其瞬间的心理活动。同时记录了19通道脑电图、2通道眼电图和肌电图。心理活动报告之后，让受试者在一些顺序量表上对其体验进行评分。共收集了241份心理活动报告。对心理活动报告之前的脑电图片段进行快速傅里叶变换分析，并比较不同状态下的频谱。全视野脑电图频谱没有显示出警觉性降低的迹象，与清醒状态的脑电图频谱非常相似，甚至显示出α活动有轻微加速。主观体验数据被归纳为四个主要成分：因素I代表主观警觉维度，这通过与脑电图频谱指数的相关性得到了证实。只有因素IV，即“专注”维度，区分了全视野状态（更高的专注度）和其他状态。在清醒状态和全视野状态下，受试者估计的过去时间段明显短于睡眠开始时的状态。结果不支持全视野意象具有入睡幻觉性质的假设。梦境般的意象可以出现在大脑的各种整体功能状态中；入睡幻觉和全视野诱发的状态应被视为更广泛的“类入睡幻觉”现象中的特殊情况。
