Song Bryan J, Sharp Slater J, Rogulja Dragana
Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
Sci Adv. 2021 Mar 24;7(13). doi: 10.1126/sciadv.abe4284. Print 2021 Mar.
Behavioral responsiveness to external stimulation is shaped by context. We studied how sensory information can be contextualized, by examining light-evoked locomotor responsiveness of relative to time of day. We found that light elicits an acute increase in locomotion (startle) that is modulated in a time-of-day-dependent manner: Startle is potentiated during the nighttime, when light is unexpected, but is suppressed during the daytime. The internal daytime-nighttime context is generated by two interconnected and functionally opposing populations of circadian neurons-LNvs generating the daytime state and DN1as generating the nighttime state. Switching between the two states requires daily remodeling of LNv and DN1a axons such that the maximum presynaptic area in one population coincides with the minimum in the other. We propose that a dynamic model of environmental light resides in the shifting connectivities of the LNv-DN1a circuit, which helps animals evaluate ongoing conditions and choose a behavioral response.
对外部刺激的行为反应是由环境塑造的。我们通过研究相对于一天中的时间的光诱发运动反应，来探究感觉信息是如何被情境化的。我们发现，光会引起运动（惊吓）的急性增加，这种增加以一种依赖于一天中时间的方式被调节：当光在意想不到的夜间出现时，惊吓反应会增强，但在白天会受到抑制。昼夜内部环境是由两组相互连接且功能相反的昼夜节律神经元产生的——产生白天状态的LNv和产生夜间状态的DN1a。在两种状态之间切换需要每天对LNv和DN1a轴突进行重塑，以使一个群体中的最大突触前面积与另一个群体中的最小突触前面积重合。我们提出，环境光的动态模型存在于LNv-DN1a回路不断变化的连接性中，这有助于动物评估当前状况并选择行为反应。
