Biology Department, University of Pennsylvania, Philadelphia, Pennsylvania.
Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania.
J Neurophysiol. 2020 Aug 1;124(2):458-470. doi: 10.1152/jn.00154.2020. Epub 2020 Jul 15.
Recent theories of norepinephrine (NE) function suggest that NE modulates the transition between stereotyped, goal-directed behavior and more variable, exploratory behaviors that facilitate learning and adaptation. We provide evidence for context-dependent switching by NE that is analogous to this explore/exploit strategy in the vocal system of the zebra finch (). Stimulation of the locus coeruleus, the major source of NE in the brain, decreases song trial-to-trial variability, transforming the variable, exploratory "undirected" song into song that resembles the more stereotyped, exploitative "directed" song that males sing to females. This behavioral switch is mediated by NE acting directly on a cortical motor nucleus that integrates inputs from a premotor cortical nucleus and a basal ganglia circuit necessary for vocal motor learning. These findings suggest that NE can act directly on the motor system to influence the transition between exploratory and exploitative behavioral strategies. Norepinephrine (NE) function is often implicated in regulating arousal levels. Recent theory suggests that the noradrenergic system also regulates the optimization of behavior with respect to reward maximization by controlling a switch between exploration and exploitation of the specific actions that yield greatest utility. We show in the songbird that NE can act directly on a cortical motor area and cause a switch between exploratory and exploitative behavior.
近期去甲肾上腺素 (NE) 功能的理论表明，NE 调节刻板的、有目标导向的行为与更可变的、探索性行为之间的转变，从而促进学习和适应。我们提供了类似斑马雀发声系统中探索/利用策略的 NE 依赖性转换的证据。刺激蓝斑核，大脑中 NE 的主要来源，减少了歌曲试验之间的可变性，将可变的、探索性的“无定向”歌曲转化为更刻板的、利用性的“定向”歌曲，雄性向雌性唱歌。这种行为转换是由 NE 直接作用于一个皮质运动核介导的，该核整合了来自一个前运动皮质核和一个基底神经节回路的输入，基底神经节回路是发声运动学习所必需的。这些发现表明，NE 可以直接作用于运动系统，影响探索性行为和利用性行为策略之间的转变。NE 功能通常与调节觉醒水平有关。最近的理论表明，去甲肾上腺素系统还通过控制对产生最大效用的特定动作的探索和利用之间的转换，来控制行为的优化，从而调节对奖励的最大化。我们在鸣禽中表明，NE 可以直接作用于皮质运动区，并导致探索性行为和利用性行为之间的转换。
