2025년 04월 29일 (화) 오후 5시

연사: 고려대 뇌공학과 민병경 교수님

제목: Thalamocortical neurodynamics in human conscious perception of mental representation

초록: Although conscious perception of mental representation is a fundamental cognitive function, its neural correlates remain unclear. It is still debated whether thalamocortical interactions play a decisive role in conscious perception. To investigate this, we used magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI), presenting flickering red and green visual cues that could be perceived either as non-fused colors or as a fused color. Using MEG, we observed 6-Hz thalamic activity associated with thalamocortical inhibitory coupling exclusively during the conscious perception of the illusory orange color. This sustained thalamic disinhibition was temporally linked with increased activation in higher visual cortical areas, providing neurophysiological evidence for the role of thalamocortical synchronization in the conscious perception of mental representations. Similarly, we found significantly different fMRI neurodynamics in higher-order thalamocortical regions compared to first-order regions. Anticorrelated neurodynamic activity was observed between the visual stream network and the default-mode network. Dynamic causal modeling consistently supported the involvement of higher-order thalamocortical iterative integration during the conscious perception of fused color, while inhibitory control was observed during the non-fusion condition. To further validate the role of higher-order thalamocortical networks in the conscious perception of mental representations, we employed non-invasive electrical brain stimulation. Application of transcranial alternating current stimulation (tACS) to the medial prefrontal cortex—a key node of the default-mode network—suppressed hemodynamic activation in higher-order subthalamic and central executive networks associated with the perception of fused colors. These findings suggest that higher-order thalamocortical and default-mode networks are crucial for the conscious perception of mental representations in humans. Taken together with our previous neuroimaging studies, our neuromodulatory results support a thalamocortical inhibitory model of consciousness, wherein both thalamic inhibitory regulation and integrative signal iteration across higher-order thalamocortical regions are essential for conscious perception of mental representation.