Hubl Daniela, Koenig Thomas, Strik Werner K, Garcia Lester Melie, Dierks Thomas
University Hospital of Psychiatry, Department of Psychiatric Neurophysiology, Bolligenstrasse 111, CH-3000 Bern 60, Switzerland.
Br J Psychiatry. 2007 Jan;190:57-62. doi: 10.1192/bjp.bp.106.022954.
Hallucinations are perceptions in the absence of a corresponding external sensory stimulus. However, during auditory verbal hallucinations, activation of the primary auditory cortex has been described.
The objective of this study was to investigate whether this activation of the auditory cortex contributes essentially to the character of hallucinations and attributes them to alien sources, or whether the auditory activation is a sign of increased general auditory attention to external sounds.
The responsiveness of the auditory cortex was investigated by auditory evoked potentials (N100) during the simultaneous occurrence of hallucinations and external stimuli. Evoked potentials were computed separately for periods with and without hallucinations; N100 power, topography and brain electrical sources were analysed.
Hallucinations lowered the N100 amplitudes and changed the topography, presumably due to a reduced left temporal responsivity.
This finding indicates competition between auditory stimuli and hallucinations for physiological resources in the primary auditory cortex. The abnormal activation of the primary auditory cortex may thus be a constituent of auditory hallucinations.
幻觉是在没有相应外部感觉刺激时产生的感知。然而，在听幻觉期间，已观察到初级听觉皮层的激活。
本研究的目的是调查听觉皮层的这种激活是否对幻觉的特征起关键作用并将其归因于外部来源，或者听觉激活是否是对外部声音的一般听觉注意力增加的标志。
在幻觉和外部刺激同时出现时，通过听觉诱发电位（N100）研究听觉皮层的反应性。分别计算有幻觉和无幻觉期间的诱发电位；分析N100功率、地形图和脑电源。
幻觉降低了N100振幅并改变了地形图，可能是由于左侧颞叶反应性降低。
这一发现表明听觉刺激和幻觉在初级听觉皮层中争夺生理资源。因此，初级听觉皮层的异常激活可能是听幻觉的一个组成部分。
