Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA; Neuroscience Institute, New York University School of Medicine, New York, NY 10016, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA.
Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA; Neuroscience Institute, New York University School of Medicine, New York, NY 10016, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA; PhD Programme in Experimental Biology and Biomedicine, Center for Neurosciences and Cell Biology, University of Coimbra, Portugal.
Brain Res. 2019 Apr 15;1709:39-49. doi: 10.1016/j.brainres.2018.05.048. Epub 2018 May 31.
Neural representations of the external world are constructed and updated in a manner that depends on behavioral context. For neocortical networks, this contextual information is relayed by a diverse range of neuromodulatory systems, which govern attention and signal the value of internal state variables such as arousal, motivation, and stress. Neuromodulators enable cortical circuits to differentially process specific stimuli and modify synaptic strengths in order to maintain short- or long-term memory traces of significant perceptual events and behavioral episodes. One of the most important subcortical neuromodulatory systems for attention and arousal is the noradrenergic locus coeruleus. Here we report that the noradrenergic system can enhance behavior in rats performing a self-initiated auditory recognition task, and optogenetic stimulation of noradrenergic locus coeruleus neurons accelerated the rate at which trained rats began correctly responding to a change in reward contingency. Animals successively progressed through distinct behavioral epochs, including periods of perseverance and exploration that occurred much more rapidly when animals received locus coeruleus stimulation. In parallel, we made recordings from primary auditory cortex and found that pairing tones with locus coeruleus stimulation led to a similar set of changes to cortical tuning profiles. Thus both behavioral and neural responses go through phases of adjustment for exploring and exploiting environmental reward contingencies. Furthermore, behavioral engagement does not necessarily recruit optimal locus coeruleus activity.
外部世界的神经表示是通过依赖于行为背景的方式构建和更新的。对于新皮层网络，这种上下文信息由多种神经调制系统传递，这些系统控制注意力并信号内部状态变量（如觉醒、动机和压力）的价值。神经调质使皮质回路能够有区别地处理特定的刺激，并调节突触强度，以维持对重要感知事件和行为事件的短期或长期记忆痕迹。对于注意力和觉醒来说，最重要的皮质下神经调制系统之一是去甲肾上腺素能蓝斑核。在这里，我们报告说，去甲肾上腺素能系统可以增强大鼠执行自主启动的听觉识别任务的行为，并且蓝斑核神经元的光遗传学刺激加速了经过训练的大鼠开始正确响应奖励关联变化的速度。动物依次经历不同的行为阶段，包括坚持不懈和探索的时期，当动物接受蓝斑核刺激时，这些时期发生得更快。与此同时，我们从初级听觉皮层进行了记录，发现将音调与蓝斑核刺激配对会导致皮质调谐曲线发生类似的变化。因此，无论是行为反应还是神经反应，都会经历探索和利用环境奖励关联的调整阶段。此外，行为参与不一定需要最佳的蓝斑核活动。
