Elucidating the Role of Dorsal Lateral Geniculate Nucleus Burst-Mode Firing in Retinal Inactivation Induced Recovery from Monocular Deprivation

弱视是一种常见的视觉系统发育障碍，导致一只眼睛的视力下降。 虽然有很多研究来了解这种疾病的病理生理学， 患有弱视的儿童和成人仍然是一个挑战。有趣的是，有临床报告显示 这表明，在成年人中，去除弱视眼后，弱视眼的视敏度可能会增加。 正常的眼睛由于受伤或疾病。受这些临床报告的启发，我们的实验室最近发现， 通过玻璃体内注射钠通道阻滞剂暂时沉默正常眼的视网膜 河豚毒素（TTX）在猫和小鼠模型中均能有效地促进视力的恢复， 弱视令人惊讶的是，这种治疗在年龄较大，更具治疗抗性的动物中有效，并且不会引起 对注射眼的任何损害。通过阐明视网膜失活促进 从动物模型中弱视饲养期的恢复，我们有可能确定如何最好地 利用这种机制来治疗人类弱视。最初的假设是， 通过TTX注射视网膜将导致背外侧膝状体核（dLGN）的活性降低， 因为dLGN将活动从视网膜传递到皮层。令人惊讶的是，这被证明是不正确的;实际上， dLGN中的神经元在视网膜失活后表现出更多的自发爆发活动。拟议 该项目将重点研究dLGN突发模式放电的增加是其机制的假设 通过视网膜失活驱动弱视的恢复。为了研究这个假设，我们首先 描述了使用慢性单位记录通过TTX进行视网膜失活后的dLGN活性。dLGN 然后，突发将被重新阻止，以确定TTX是否需要dLGN突发 介导的从弱视养育中恢复。最后，dLGN爆发样活性将通过光遗传学方法施加。 操作，以确定爆发是否足以驱动从弱视期恢复 养育通过加深我们对dLGN活性在视网膜失活诱导的恢复中的作用的理解， 从弱视的饲养，这个项目有可能为我们未来的研究提供信息，并提出新的临床 治疗弱视的方法。该项目将在大脑中的Mark Bear博士的实验室进行， 认知科学系（BCS）在马萨诸塞州理工学院（MIT）。熊实验室 包含拟议项目所需的所有设备。关于所需实验室的所有必要培训 技术将由高级实验室成员或通过与BCS的其他实验室合作提供。熊 实验室，BCS和麻省理工学院将提供优质的科学和专业发展资源，以促进成功的 过渡到申请人的研究生涯的下一阶段。

Amblyopia is a common disorder of visual system development, resulting in poor visual acuity in one eye. Though there has been much research to understand the pathophysiology of the disorder, treating older children and adults with amblyopia remains a challenge. Interestingly, there have been clinical reports suggesting gains in the visual acuity of the amblyopic eye may be possible in adults following removal of the normal eye due to injury or disease. Motivated by these clinical reports, our lab recently discovered that temporarily silencing the retina of the normal eye via intravitreal injection of the sodium channel blocker tetrodotoxin (TTX) is effective at promoting a recovery in visual acuity in both cat and mouse models of amblyopia. Amazingly, this treatment is effective in older, more treatment resistant animals and does not cause any penalty to the injected eye. By elucidating the mechanism by which retinal inactivation is promoting recovery from a period of amblyopic rearing in animal models, we have the potential to determine how to best exploit this mechanism for the treatment of human amblyopia. It was initially hypothesized that silencing the retina via TTX injection would result in reduced activity in the dorsal lateral geniculate nucleus (dLGN), because the dLGN relays activity from retina to cortex. Surprisingly, this turned out to be incorrect; in actuality, neurons in the dLGN exhibit more spontaneous bursting activity following retinal inactivation. The proposed project will focus on investigating the hypothesis that this increase in dLGN burst mode firing is the mechanism by which retinal inactivation drives recovery from amblyopic rearing. To investigate this hypothesis, we will first describe dLGN activity following retinal inactivation via TTX with the use of chronic unit recordings. dLGN bursting will then be pharmacologically blocked to determine whether dLGN bursting is necessary for TTX mediated recovery from amblyopic rearing. Finally, dLGN burst-like activity will be imposed via optogenetic manipulation in order to determine whether bursting is sufficient to drive recovery from a period of amblyopic rearing. By enhancing our understanding of the role of dLGN activity in retinal inactivation induced recovery from amblyopic rearing, this project has the potential to inform our future research and suggest novel clinical approaches for treating amblyopia. This project will be carried out in the lab of Dr. Mark Bear in the Brain and Cognitive Sciences Department (BCS) at the Massachusetts Institute of Technology (MIT). The Bear lab contains all required equipment for the proposed project. All necessary training regarding required laboratory techniques will be provided by senior lab members or through collaboration with other labs in BCS. The Bear lab, BCS, and MIT will offer quality scientific and professional development resources to facilitate a successful transition into the next stage of the applicant’s research career.