Förster Jona, Nierhaus Till, Schröder Pia, Blankenburg Felix
Neurocomputation and Neuroimaging Unit, Freie Universität Berlin, Habelschwerdter Allee 45, 14195, Berlin, Germany.
Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, 10117, Berlin, Germany.
Sci Rep. 2025 Mar 5;15(1):7674. doi: 10.1038/s41598-025-91580-1.
The neural correlates of conscious somatosensory perception are usually investigated using threshold detection tasks. However, it is largely unclear how other aspects of conscious somatosensory experience, such as localization, discrimination, and identification, are processed in the brain. Here, we go beyond mere stimulus detection and analyze the EEG data of 34 participants to investigate the event-related potential correlates of somatosensory experience in a temporal discrimination task. We show that the perceptual experience of feeling one vs. two pulses for identical pairs of electrical stimuli is reflected in positive fronto-central ERP activity after ~ 150 ms, even when controlling for task-relevance and post-perceptual processes such as decision-making and response preparation. This effect is a modulation of an ERP component that peaks considerably later at 170 ms and in a different sensor region than the detection-related so-called N140, which was not modulated by our task. Distributed source reconstruction of the sensor-level effect suggested the contralateral primary somatosensory cortex as its origin. We therefore propose that conscious detection and temporal discrimination are likely to both involve early sensory areas but recruit different neuronal processes. Our result adds to the growing body of research investigating the mechanisms underlying different aspects of conscious experience.
意识体感知觉的神经关联通常使用阈值检测任务进行研究。然而，意识体感体验的其他方面，如定位、辨别和识别，在大脑中是如何处理的，目前还很不清楚。在这里，我们超越了单纯的刺激检测，分析了34名参与者的脑电图数据，以研究时间辨别任务中体感体验的事件相关电位关联。我们发现，即使在控制任务相关性以及诸如决策和反应准备等知觉后过程的情况下，对于相同的电刺激对，感觉到一个脉冲与两个脉冲的知觉体验在约150毫秒后会反映在额中央区的正性ERP活动中。这种效应是对一个ERP成分的调制，该成分在170毫秒时达到峰值，且出现在与检测相关的所谓N140不同的感觉区域，我们的任务并未对N140产生调制作用。传感器水平效应的分布式源重建表明其起源于对侧初级体感皮层。因此，我们提出，意识检测和时间辨别可能都涉及早期感觉区域，但招募了不同的神经元过程。我们的结果为研究意识体验不同方面背后机制的不断增加的研究成果增添了内容。
