正弦电流前庭刺激期间知觉反应的大脑皮层和皮层下相关因素：一项BOLD fMRI研究。

文献信息

中文摘要

背景： 支撑晕动病的皮层和皮层下神经环路目前了解甚少。然而，某些区域——包括孤束核（NTS）和顶岛前庭皮层（PIVC）——已知参与恶心的产生。尤其是PIVC，被认为在前庭输入的处理中发挥重要作用。我们此前曾使用低频正弦电流前庭刺激（sGVS）来诱发左右方向运动的知觉，这也会在约40%的人群中诱发恶心。虽然sGVS此前已与脑成像结合用于研究前庭通路，但那些研究使用的是较短的刺激时段（约30秒），并未诱发恶心。方法：在此，我们使用功能磁共振成像（fMRI）记录了17名参与者在基线期（5分钟）、持续较长时间的低频sGVS期间（±2 mA，0.08 Hz，100个周期；约21分钟）以及恢复期（9分钟）的血氧水平依赖（BOLD）信号强度变化。结果：然而令人意外的是，只有四名参与者在刺激期间报告了初现或明显的恶心。尽管如此，有两个区域显示出与长时程（相对于此前使用的短时程）刺激相关的BOLD信号强度变化：伏隔核和蓝斑。结论：尽管恶心的感觉不如预期那样明显（或许是由于参与者必须采取仰卧位且头部固定不动），但这些区域似乎与较长时间的前庭刺激更为相关，这可能是诱发恶心感觉所必需的。

英文摘要

The cortical and subcortical circuitry underpinning motion sickness is poorly understood. However, certain regions - including the nucleus of the solitary tract (NTS) and the parieto-insular vestibular cortex (PIVC) - are known to be involved in the generation of nausea. The PIVC, in particular, is believed to serve an important role in the processing of vestibular inputs. We have previously used low-frequency sinusoidal galvanic vestibular stimulation (sGVS) to induce perceptions of side-to-side motion, which also induces nausea in ~ 40% of people. While sGVS has been previously used with brain imaging to investigate vestibular pathways, those studies used shorter bouts of stimulation (~ 30 s) which did not induce nausea. Here, we have used functional magnetic resonance imaging (fMRI) to record blood-oxygen-level-dependent (BOLD) signal-intensity changes at baseline (5 min), during low-frequency sGVS for a sustained period of time (± 2 mA, 0.08 Hz, 100 cycles; ~21 min) and during a recovery period (9 min) in 17 participants. Surprisingly, however, only four participants reported incipient or overt nausea during stimulation. Nevertheless, two regions displayed BOLD signal-intensity changes associated with the long-form (as opposed to previously used short-form) stimulation: the nucleus accumbens and locus coeruleus. Though sensations of nausea were not as apparent as expected (perhaps due to the necessity of participants adopting a supine position with their heads fixed in place), these regions would appear to be more associated with a longer period of vestibular stimulation, perhaps required to evoke sensations of nausea.