Schubert Ruth, Blankenburg Felix, Lemm Steven, Villringer Arno, Curio Gabriel
Department of Neurology, Charité-University Medicine, Campus Mitte, Berlin, Germany.
Psychophysiology. 2006 Jan;43(1):31-40. doi: 10.1111/j.1469-8986.2006.00379.x.
We investigated correlates of somatosensory awareness for supra theshold stimuli using event-related potentials in a masking paradigm: Conscious perception of a weak, but suprathreshold "target" stimulus was suppressed in a significant number of trials when followed by a higher-intensity "mask" stimulus. ERPs were compared for trials with perceived versus unperceived target stimuli. Early ERPs (P60, N80), generated in the contralateral S1, were found independent of stimulus perception. In contrast, for consciously perceived target stimuli, amplitude enhancements were observed for the P100 and N140. Thus, early activation of S1 is not sufficient to warrant conscious stimulus perception. Conscious stimulus processing differs significantly from unconscious processing starting around 100 ms after stimulus presentation when the signal is processed in parietal and frontal cortices, brain regions crucial for stimulus access into conscious perception.
当一个较弱但阈上的“目标”刺激之后紧接着一个更高强度的“掩蔽”刺激时，在相当数量的试验中，对该目标刺激的有意识感知会受到抑制。对目标刺激被感知和未被感知的试验的事件相关电位进行了比较。发现在对侧初级体感皮层产生的早期事件相关电位（P60、N80）与刺激感知无关。相反，对于有意识感知到的目标刺激，在P100和N140处观察到了波幅增强。因此，初级体感皮层的早期激活不足以保证有意识的刺激感知。当信号在顶叶和额叶皮层（对刺激进入有意识感知至关重要的脑区）进行处理时，有意识的刺激处理与刺激呈现后约100毫秒开始的无意识处理有显著差异。
