Distinct retinohypothalamic innervation patterns predict the developmental emergence of species-typical circadian phase preference in nocturnal Norway rats and diurnal nile grass rats.
Distinct retinohypothalamic innervation patterns predict the developmental emergence of species-typical circadian phase preference in nocturnal Norway rats and diurnal nile grass rats.
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不同的视网膜下丘脑神经支配模式预测了夜间活动的挪威大鼠和昼间尼罗河草大鼠物种典型昼夜节律相位偏好的发育出现。
DOI：
10.1002/cne.23098
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
Blumberg,MarkS
中科院分区：
文献类型：
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作者：
Todd,WilliamD;Gall,AndrewJ;Weiner,JoshuaA;Blumberg,MarkS
大脑如何以不同的方式发育来支持某些哺乳动物的夜间活动，而另一些哺乳动物则支持白天活动？为了回答这个问题，人们可以看看视交叉上核（SCN），它通过视网膜下丘脑束（RHT）被光夹带。然而，由于迄今为止研究的所有哺乳动物的视交叉上核在白天更加活跃，因此仅靠它无法确定昼夜节律相位偏好。在夜间活动的成年挪威大鼠 (Rattusnorvegicus) 中，RHT 也投射到腹侧室旁区 (vSPVZ)，这是一个表达 SCN-vSPVZ 神经元活动同相模式的相邻区域。相比之下，在昼夜活动的成年尼罗草大鼠（Arvicanthis niloticus）中，表达了 SCN-vSPVZ 神经元活动的反相模式。我们假设这些物种差异部分是由于草鼠 RHT 到 vSPVZ 投射较弱或缺失造成的。在这里，我们使用发育比较方法评估了行为、下丘脑活动和 RHT 解剖学方面的物种差异。我们报告称，挪威大鼠在出生后第二周结束时，当夜间觉醒和神经元活动的同相模式出现时，会出现强烈的视网膜到 vSPVZ 投射。然而，在草鼠中，这种投射不会发展，并且在出生后第二周反相位模式的出现伴随着昼间觉醒的增加。考虑到先前发表的关于多种物种 RHT 预测的报告，当前的研究结果表明，视网膜与下丘脑的连接方式和时间会以不同的方式塑造大脑和行为，从而产生占据相反时间生态位的动物。 J.Comp。 Neurol.，520：3277–3292，2012 年。© 2012 Wiley periodicals, Inc.
How does the brain develop differently to support nocturnality in some mammals, but diurnality in others? To answer this question, one might look to the suprachiasmatic nucleus (SCN), which is entrained by light via the retinohypothalamic tract (RHT). However, because the SCN is more active during the day in all mammals studied thus far, it alone cannot determine circadian phase preference. In adult Norway rats (Rattus norvegicus), which are nocturnal, the RHT also projects to the ventral subparaventricular zone (vSPVZ), an adjacent region that expresses an in‐phase pattern of SCN‐vSPVZ neuronal activity. In contrast, in adult Nile grass rats (Arvicanthis niloticus), which are diurnal, an anti‐phase pattern of SCN‐vSPVZ neuronal activity is expressed. We hypothesized that these species differences result in part from a weak or absent RHT‐to‐vSPVZ projection in grass rats. Here, using a developmental comparative approach, we assessed species differences in behavior, hypothalamic activity, and RHT anatomy. We report that a robust retina‐to‐vSPVZ projection develops in Norway rats around the end of the second postnatal week when nocturnal wakefulness and the in‐phase pattern of neuronal activity emerge. In grass rats, however, such a projection does not develop and the emergence of the anti‐phase pattern during the second postnatal week is accompanied by increased diurnal wakefulness. When considered within the context of previously published reports on RHT projections in a variety of species, the current findings suggest that how and when the retina connects to the hypothalamus differentially shapes brain and behavior to produce animals that occupy opposing temporal niches. J. Comp. Neurol., 520:3277–3292, 2012. © 2012 Wiley Periodicals, Inc.