Hale Joanne R, White Thomas P, Mayhew Stephen D, Wilson Rebecca S, Rollings David T, Khalsa Sakhvinder, Arvanitis Theodoros N, Bagshaw Andrew P
School of Psychology, University of Birmingham, Birmingham, UK.
School of Psychology, University of Birmingham, Birmingham, UK.
Neuroimage. 2016 Jan 15;125:657-667. doi: 10.1016/j.neuroimage.2015.10.041. Epub 2015 Oct 21.
The transition from wakefulness into sleep is accompanied by modified activity in the brain's thalamocortical network. Sleep-related decreases in thalamocortical functional connectivity (FC) have previously been reported, but the extent to which these changes differ between thalamocortical pathways, and patterns of intra-thalamic FC during sleep remain untested. To non-invasively investigate thalamocortical and intra-thalamic FC as a function of sleep stage we recorded simultaneous EEG-fMRI data in 13 healthy participants during their descent into light sleep. Visual scoring of EEG data permitted sleep staging. We derived a functional thalamic parcellation during wakefulness by computing seed-based FC, measured between thalamic voxels and a set of pre-defined cortical regions. Sleep differentially affected FC between these distinct thalamic subdivisions and their associated cortical projections, with significant increases in FC during sleep restricted to sensorimotor connections. In contrast, intra-thalamic FC, both within and between functional thalamic subdivisions, showed significant increases with advancement into sleep. This work demonstrates the complexity and state-specific nature of functional thalamic relationships--both with the cortex and internally--over the sleep/wake cycle, and further highlights the importance of a thalamocortical focus in the study of sleep mechanisms.
从清醒状态过渡到睡眠状态伴随着大脑丘脑皮质网络活动的改变。此前已有报道称，与睡眠相关的丘脑皮质功能连接（FC）会下降，但这些变化在丘脑皮质通路之间的差异程度以及睡眠期间丘脑内FC的模式仍未得到验证。为了以非侵入性方式研究丘脑皮质和丘脑内FC与睡眠阶段的关系，我们在13名健康参与者进入浅睡眠状态时同步记录了脑电图-功能磁共振成像（EEG-fMRI）数据。通过对脑电图数据进行视觉评分来确定睡眠阶段。我们通过计算丘脑体素与一组预定义皮质区域之间基于种子点的FC，在清醒状态下得出了功能性丘脑分区。睡眠对这些不同丘脑亚区与其相关皮质投射之间的FC有不同影响，睡眠期间FC的显著增加仅限于感觉运动连接。相比之下，功能性丘脑亚区内以及之间的丘脑内FC随着睡眠加深而显著增加。这项研究揭示了在睡眠/清醒周期中，丘脑功能关系——与皮质之间以及丘脑内部——的复杂性和状态特异性本质，并进一步强调了丘脑皮质聚焦在睡眠机制研究中的重要性。
