The impact of temporal modulations in irradiance under light adapted conditions on the mouse suprachiasmatic nuclei (SCN).
The impact of temporal modulations in irradiance under light adapted conditions on the mouse suprachiasmatic nuclei (SCN).
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DOI：
10.1038/s41598-017-11184-2
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发表时间：
2017-09-05
影响因子：
4.6
通讯作者：
Lucas RJ
中科院分区：
文献类型：
--
作者：
Dobb R;Martial F;Elijah D;Storchi R;Brown TM;Lucas RJ
SCN神经元对光步的电生理反应已经建立，但对更自然的辐射调节的反应研究得少得多。我们首先通过显示人类受试者的辐照度变化偏向于低时间频率和小幅度来解决这一缺陷。利用细胞外记录，我们发现小鼠SCN中的神经元对具有这些特征的刺激有反应，在较低的时间频率下最好地跟踪辐照度的正弦调制，并在一系列常见对比中响应辐照度的突然变化。这些光适应反应的光谱灵敏度表明，它们主要是由视锥细胞驱动的，但黑视素（和/或视杆细胞）在更渐进的变化中起作用。较高频率的辐照调制适度增加了SCN神经元的平均放电时间（通常被认为是对背景光强度进行编码），但对光的昼夜节律相位重置效率没有可检测的影响。我们的研究结果强调了SCN对辐照度的自然时间调制进行编码的能力，同时揭示了昼夜节律系统可以随着时间的推移有效地整合这些信号，从而使相位重置反应保持与平均光照成正比。
Electrophysiological responses of SCN neurons to light steps are well established, but responses to more natural modulations in irradiance have been much less studied. We address this deficit first by showing that variations in irradiance for human subjects are biased towards low temporal frequencies and small magnitudes. Using extracellular recordings we show that neurons in the mouse SCN are responsive to stimuli with these characteristics, tracking sinusoidal modulations in irradiance best at lower temporal frequencies and responding to abrupt changes in irradiance over a range of commonly encountered contrasts. The spectral sensitivity of these light adapted responses indicates that they are driven primarily by cones, but with melanopsin (and/or rods) contributing under more gradual changes. Higher frequency modulations in irradiance increased time averaged firing of SCN neurons (typically considered to encode background light intensity) modestly over that encountered during steady exposure, but did not have a detectable effect on the circadian phase resetting efficiency of light. Our findings highlight the SCN’s ability to encode naturalistic temporal modulations in irradiance, while revealing that the circadian system can effectively integrate such signals over time such that phase-resetting responses remain proportional to the mean light exposure.
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影响因子：
16.2
作者：
Lall, Gurprit S.;Revell, Victoria L.;Momiji, Hiroshi;Al Enezi, Jazi;Altimus, Cara M.;Gueler, Ali D.;Aguilar, Carlos;Cameron, Morven A.;Allender, Susan;Hankins, Mark W.;Lucas, Robert J.
通讯作者：
Lucas, Robert J.
影响因子：
25
作者：
Altimus, Cara M.;Gueler, Ali D.;Alam, Nazia M.;Arman, A. Cyrus;Prusky, Glen T.;Sampath, Alapakkam P.;Hattar, Samer
通讯作者：
Hattar, Samer
影响因子：
3.7
作者：
Brown TM;Allen AE;al-Enezi J;Wynne J;Schlangen L;Hommes V;Lucas RJ
通讯作者：
Lucas RJ
影响因子：
5.5
作者：
Brown, Timothy M.;Wynne, Jonathan;Lucas, Robert J.
通讯作者：
Lucas, Robert J.
影响因子：
4.4
作者：
Vartanian, Garen V.;Zhao, Xiwu;Wong, Kwoon Y.
通讯作者：
Wong, Kwoon Y.