据4月24日的《科学》杂志报道说，一项新型的脑成像研究可能帮助人们解释为什么有些人在清晨思维最为敏捷，而另外一些人则在傍晚的时候变得最有效率。 Christina Schmidt及其在比利时和瑞士的同僚现在报告说，我们的思维敏捷程度及思想集中的能力受到了我们已经醒了多久以及当时在一天中所处的时间的双重影响，因为我们的生物钟节奏是根据日-夜周期运作的。
研究人员应用功能性核磁共振成像来对早起者和夜猫子的脑部活动进行监控。这些人在连续两个夜晚呆在一个睡眠实验室中，并周期性地从事一项需要保持持续注意力的作业。 研究的结果提示，一般来说，夜猫子在他们发生脑疲劳之前，其清醒的时间会比早起者长。 在清醒10个小时之后，与夜猫子相比，早起者的与注意力有关系的脑部区域的活动性会有所下降。 早起者还更容易感到困乏，并容易使作业操作变得更慢。 这些脑区域包括生物主时钟的所在地。 该区域的活动会降低实验自愿者清醒的时间（即“睡眠压力”增加了），提示早起者和夜猫子之间的行为差异至少有一部份与控制睡眠压力和生理节奏有关的脑区域间的相互作用的结果有关。（生物谷Bioon.com）
生物谷推荐原始出处：
Science 24 April 2009:DOI: 10.1126/science.1167337
Homeostatic Sleep Pressure and Responses to Sustained Attention in the Suprachiasmatic Area
Christina Schmidt,1,2,* Fabienne Collette,1,2 Yves Leclercq,1 Virginie Sterpenich,1 Gilles Vandewalle,1 Pierre Berthomier,3 Christian Berthomier,3 Christophe Phillips,1 Gilberte Tinguely,1 Annabelle Darsaud,1 Steffen Gais,1 Manuel Schabus,1 Martin Desseilles,1 Thien Thanh Dang-Vu,1 Eric Salmon,1 Evelyne Balteau,1 Christian Degueldre,1 André Luxen,1 Pierre Maquet,1 Christian Cajochen,4 Philippe Peigneux1,5,*
Throughout the day, cognitive performance is under the combined influence of circadian processes and homeostatic sleep pressure. Some people perform best in the morning, whereas others are more alert in the evening. These chronotypes provide a unique way to study the effects of sleep-wake regulation on the cerebral mechanisms supporting cognition. Using functional magnetic resonance imaging in extreme chronotypes, we found that maintaining attention in the evening was associated with higher activity in evening than morning chronotypes in a region of the locus coeruleus and in a suprachiasmatic area (SCA) including the circadian master clock. Activity in the SCA decreased with increasing homeostatic sleep pressure. This result shows the direct influence of the homeostatic and circadian interaction on the neural activity underpinning human behavior.
1 Cyclotron Research Centre, University of Liège, 4000 Liège, Belgium.
2 Cognitive and Behavioral Neuroscience Centre, University of Liège, 4000 Liège, Belgium.
3 PHYSIP S.A., 75011 Paris, France.
4 Centre for Chronobiology, Psychiatric Hospital of the University of Basel, CH-4025 Basel, Switzerland.
5 Neuropsychology and Functional Neuroimaging Research Unit (UR2NF), Université Libre de Bruxelles, B-1050 Brussels, Belgium.
