Institute of Psychology, Leiden University, Leiden, Netherlands.
Donders Institute, Centre for Cognitive Neuroimaging, Radboud University Nijmegen, Nijmegen, Netherlands.
Elife. 2023 Jun 27;12:e84822. doi: 10.7554/eLife.84822.
Neuromodulatory nuclei that are part of the ascending arousal system (AAS) play a crucial role in regulating cortical state and optimizing task performance. Pupil diameter, under constant luminance conditions, is increasingly used as an index of activity of these AAS nuclei. Indeed, task-based functional imaging studies in humans have begun to provide evidence of stimulus-driven pupil-AAS coupling. However, whether there is such a tight pupil-AAS coupling during rest is not clear. To address this question, we examined simultaneously acquired resting-state fMRI and pupil-size data from 74 participants, focusing on six AAS nuclei: the locus coeruleus, ventral tegmental area, substantia nigra, dorsal and median raphe nuclei, and cholinergic basal forebrain. Activation in all six AAS nuclei was optimally correlated with pupil size at 0-2 s lags, suggesting that spontaneous pupil changes were almost immediately followed by corresponding BOLD-signal changes in the AAS. These results suggest that spontaneous changes in pupil size that occur during states of rest can be used as a noninvasive general index of activity in AAS nuclei. Importantly, the nature of pupil-AAS coupling during rest appears to be vastly different from the relatively slow canonical hemodynamic response function that has been used to characterize task-related pupil-AAS coupling.
参与上行觉醒系统 (AAS) 的神经调节核在调节皮质状态和优化任务表现方面发挥着关键作用。在恒定亮度条件下，瞳孔直径越来越多地被用作这些 AAS 核活动的指标。事实上，人类基于任务的功能成像研究已经开始提供刺激驱动的瞳孔-AAS 耦合的证据。然而，在休息期间是否存在如此紧密的瞳孔-AAS 耦合尚不清楚。为了解决这个问题，我们同时检查了 74 名参与者的静息状态 fMRI 和瞳孔大小数据，重点关注六个 AAS 核：蓝斑、腹侧被盖区、黑质、中缝背核和中缝正中核以及胆碱能基底前脑。在 0-2 秒的滞后时间内，所有六个 AAS 核的激活与瞳孔大小呈最佳相关性，这表明自发的瞳孔变化几乎立即伴随着 AAS 中的相应 BOLD 信号变化。这些结果表明，在休息状态下发生的自发瞳孔大小变化可以用作 AAS 核活动的非侵入性一般指标。重要的是，休息期间瞳孔-AAS 耦合的性质与用于描述与任务相关的瞳孔-AAS 耦合的相对较慢的经典血流动力学响应函数有很大不同。
