Laboratory of Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
Sleep. 2018 Jun 1;41(6). doi: 10.1093/sleep/zsy051.
The lateral hypothalamus (LH) is a relatively large hypothalamic structure containing several neurochemically different, but spatially intermingled, neuronal populations. While the role of these neurons in the homeostatic regulation of diverse physiological and behavioral functions such as sleep/wake cycle has been studied extensively, the impact of sleep history on the electrophysiology of the LH and whether this effect is homogenous across LH is unknown. By combining multiunit activity (MUA) recordings in different regions of LH with electroencephalogram recordings in freely moving rats, we unravelled a heterogeneity of neural-activity patterns within different subregions of LH. This heterogeneity was evident in both the circadian and the vigilance state-dependent modulation of MUA. Interestingly, and consistent with this heterogeneity under baseline conditions, the magnitude of MUA suppression following 6 hr of sleep deprivation (SD) was also different within different locations of LH. Unlike the cortex and in contrast to the predictions of the synaptic homeostatic hypothesis, no correlation was found between the magnitude of activity increase during SD and the percentage of suppression of MUA during recovery sleep. These data provide in vivo evidence of a functional heterogeneity in the circadian and homeostatic modulation of neuronal activity in LH.
外侧下丘脑 (LH) 是一个相对较大的下丘脑结构，包含几个神经化学不同但空间交织的神经元群体。虽然这些神经元在睡眠/觉醒周期等多种生理和行为功能的稳态调节中的作用已经得到了广泛的研究，但睡眠史对 LH 电生理学的影响以及这种影响是否在 LH 中是均匀的尚不清楚。通过将多单位活动 (MUA) 在 LH 的不同区域的记录与自由移动大鼠的脑电图记录相结合，我们揭示了 LH 不同亚区内部神经活动模式的异质性。这种异质性在 MUA 的昼夜节律和警觉状态依赖性调制中都很明显。有趣的是，与基线条件下的这种异质性一致，在 LH 的不同位置，经过 6 小时的睡眠剥夺 (SD) 后 MUA 抑制的幅度也不同。与皮层不同，与突触稳态假说的预测相反，在 SD 期间活动增加的幅度与恢复睡眠期间 MUA 抑制的百分比之间没有发现相关性。这些数据提供了体内证据，证明 LH 中神经元活动的昼夜节律和稳态调节存在功能异质性。
