Enhancing Dendritic Inhibition for the Control of Critical Period Plasticity

项目摘要/摘要 在全球范围内，数以百万计的人因受伤、退化或神经形成不当而丧失视力。 视觉系统内的电路。虽然有许多努力来再生视觉皮质的输入，但任何 成功的治疗必须包括将新的输入整合到现有的大脑皮层回路中。在正常期间 视觉发育，这是由于在有限的时间窗口内感觉可塑性增强的结果， 被称为关键时期。目前尚不清楚成年期的关键期可塑性如何重新开启。 寻求有效的治疗策略。此外，抑制和胆碱能调节是已知的成分 关键时期的可塑性，但尚未联系起来。我的初步数据显示了一条共同的途径 这些机制：在主要的抑制性中间神经元组中，只有生长抑素表达(SST) 在关键期结束时，中间神经元在注意力视觉过程中的反应发生逆转。 虽然已知SST中间神经元在成人注意过程中调节锥体细胞树突活动，但它是 尚不清楚胆碱能输入如何直接作用于SST中间神经元改变树突状细胞活动 临界时期塑性。我的工作假设是，SST细胞调制的变化改变了树突状细胞 学习规则，结束关键期。在这里，我提出了两个具体目标，以应对重新 在成年大脑皮质中建立强大的可塑性。在目标1中，为了了解胆碱能输入是如何 在向成年期的转变中，我将测试不同年龄组的SST中间神经元的胆碱能输入 使用通道视紫红质辅助的电路标测。在目标2中，我将使用活体双光子显微镜来 比较正常的SST反应与缺乏胆碱能受体拮抗剂Lynx1的小鼠的反应，Lynx1 是关键时期关闭的重要组成部分。这些目标应该会促进对电路层面的理解 研究成年期的可塑性如何变得有限，并将为视力障碍的新治疗策略提供信息。

Project Summary/Abstract Globally, millions of people suffer loss of vision as a result of injury, degeneration, or improperly formed neural circuitry within the visual system. While there are many efforts to regenerate inputs to the visual cortex, any successful therapy must include the integration of new inputs into existing cortical circuitry. During normal visual development, this occurs as a result of heightened sensory plasticity during a limited time window, referred to as a critical period. It is not understood how critical period plasticity can be re-opened in adulthood for effective therapeutic strategies. Furthermore, inhibition and cholinergic modulation are known components of critical period plasticity but have yet to be linked. My preliminary data demonstrates a common pathway for these mechanisms: out of the major inhibitory interneuron groups, only somatostatin-expressing (SST) interneurons undergo a reversal in their response during attentive vision at the closure of the critical period. While it is known that SST interneurons mediate pyramidal cell dendritic activity during attention in adults, it is not known how cholinergic inputs are directly acting on SST interneurons to alter dendritic activity during critical period plasticity. My working hypothesis is that the shift in modulation of SST cells alters dendritic learning rules to close the critical period. Here I am proposing two specific aims to address the challenge of re- establishing strong plasticity in the adult cortex. In Aim 1, in order to understand how cholinergic inputs may be changing in the transition to adulthood, I will test cholinergic inputs to SST interneurons across age groups using channelrhodopsin-assisted circuit mapping. In Aim 2, I will use in vivo two-photon microscopy to compare normal SST responses to those seen in mice lacking a cholinergic receptor antagonist, Lynx1, which is an essential component for critical period closure. These aims should advance a circuit-level understanding of how plasticity becomes limited in adulthood and will inform novel therapeutic strategies for visual disorders.