Yokoyama K, Farner D S
Science. 1978 Jul 7;201(4350):76-9. doi: 10.1126/science.566467.
Daily 20-hour encephalic photophases (DEPP), transmitted (hours 0 to 20) via chronically implanted light-conducting fibers to selected sites in the basal hypothalamus of male white-crowned sparrows, were superimposed on daily 8-hour (hours 0 to 8) external ambient photophases (DAPP). Initially the birds displayed motor activity only during the 8-hour DAPP. After a delay of at least 2 weeks, some of the birds became intensively active during hours 8 to 20. We postulate that this period of "nocturnal" activity is equivalent to the nocturnal Zugunruhe shown by caged individuals of many nocturnally migratory species subjected to long days; such activity is generally regarded as the expression of migratory behavior.
每天20小时的脑部光照期（DEPP），通过长期植入的光导纤维在0至20小时传输至雄性白冠雀基底下丘脑的选定部位，叠加在每天8小时（0至8小时）的外部环境光照期（DAPP）上。最初，这些鸟只在8小时的DAPP期间表现出运动活动。至少延迟2周后，一些鸟在8至20小时变得极度活跃。我们推测，这段“夜间”活动期等同于许多在长日照条件下笼养的夜行性迁徙物种个体所表现出的夜间 Zugunruhe；这种活动通常被视为迁徙行为的表现。
