Jang Hyunwoo, Fotiadis Panagiotis, Mashour George A, Hudetz Anthony G, Huang Zirui
Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA.
Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
bioRxiv. 2024 Oct 10:2024.10.07.617034. doi: 10.1101/2024.10.07.617034.
The neural basis of conscious perception remains incompletely understood. While cortical mechanisms of conscious content have been extensively investigated, the role of subcortical structures, including the thalamus, remains less explored. We aim to elucidate the causal contributions of different thalamic regions to conscious perception using transcranial low-intensity focused ultrasound (LIFU) neuromodulation. We hypothesize that modulating different thalamic regions would result in distinct perceptual outcomes. We apply LIFU in human volunteers to investigate region-specific and sonication parameter-dependent effects. We target anterior (transmodal-dominant) and posterior (unimodal-dominant) thalamic regions, further divided into ventral and dorsal regions, while participants perform a near-threshold visual perception task. Task performance is evaluated using Signal Detection Theory metrics. We find that the high duty cycle stimulation of the ventral anterior thalamus enhanced object recognition sensitivity. We also observe a general (i.e., region-independent) effect of LIFU on decision bias (i.e., a tendency toward a particular response) and object categorization accuracy. Specifically, high duty cycle stimulation decreases categorization accuracy, whereas low duty cycle shifts decision bias towards a more conservative stance. In conclusion, our results provide causal insight into the functional organization of the thalamus in shaping human visual experience and highlight the unique role of the transmodal-dominant ventral anterior thalamus.
意识知觉的神经基础仍未被完全理解。虽然对意识内容的皮层机制已进行了广泛研究，但包括丘脑在内的皮层下结构的作用仍较少被探索。我们旨在使用经颅低强度聚焦超声（LIFU）神经调节来阐明不同丘脑区域对意识知觉的因果贡献。我们假设调节不同的丘脑区域会导致不同的知觉结果。我们在人类志愿者中应用LIFU，以研究区域特异性和超声参数依赖性效应。当参与者执行接近阈值的视觉知觉任务时，我们针对丘脑的前部（跨模式主导）和后部（单模式主导）区域，进一步分为腹侧和背侧区域。使用信号检测理论指标评估任务表现。我们发现，腹侧前丘脑的高占空比刺激增强了物体识别敏感性。我们还观察到LIFU对决策偏差（即倾向于特定反应）和物体分类准确性的一般（即与区域无关）效应。具体而言，高占空比刺激会降低分类准确性，而低占空比会使决策偏差转向更保守的立场。总之，我们的结果为丘脑在塑造人类视觉体验中的功能组织提供了因果性见解，并突出了跨模式主导的腹侧前丘脑的独特作用。
