Project 1

摘要 小鼠--妊娠期短，寿命短，产仔数大，最重要的是，遗传易驯服 - 是探索哺乳动物大脑发育的强大实验工具。一 一个突出的例子是自闭症风险基因的可逆性破坏，如Mecp 2或Shank 3。 在成熟的表型出现后打开这些基因可以挽救几个运动- 相关症状，包括惯性，步态异常，体重，呼吸不规则，重复 梳理或后肢紧握。相反，其他神经学方面的问题没有得到纠正， 成年期，如焦虑或运动协调。对于人类患者来说， 尚不清楚Shank 3或Mecp 2突变小鼠的高级认知受损程度 以及复苏是否也将限于一个关键时期。Hensch项目将直接 解决敏感期和背内侧前额叶皮层（dmPFC）功能的可逆性 使用新的注意力、认知灵活性和声学偏好的行为测试沿着 相关区域的相关生理测量。第一阶段的开拓性工作 康特中心建立了关键的抑制性神经元的关键作用， 老鼠感觉系统中的周期计时。小清蛋白（PV+）GABA回路成熟决定 这些电路改进窗口的开始和关闭。精神科操作 风险因素，如生物钟基因破坏或氧化还原失调，可以延迟或延长 局部电路易损PV+元件破坏的发展轨迹 兴奋抑制平衡最近，Hensch和Feng将这一原理推广到高阶 岛叶皮层的多感觉整合（MSI，自闭症患者通常受损）。 缺乏Shank 3（弱PV+）或Mecp 2（过量PV+）的小鼠中的共有MSI损伤 建议PV+网络功能的最佳范围，可以适当修剪 - 是的在这里，我们将研究电路生理和解剖之前/之后恢复柄3 或Mecp 2，最终通过完全3D EM电路重建，Lichtman也在 携带相同Shank 3缺失的绒猴（来自Feng）。此外，我们的触摸屏2- 选择视觉注意力测定，多项选择觅食任务，以评估灵活的规则学习， 以及对生命早期所经历的听觉刺激（音乐、超声波）的偏好， 突变小鼠和获救小鼠的dmPFC功能。电生理记录与双光子 体内dmPFC的钙/氯化物成像将重点关注这些区域的PV+网络 从与阿洛塔的人类类器官的比较开始。基于这些 从小鼠的许多见解，沉默/激活PV+电路的影响，在相应的额叶 使用病毒DREADD的局灶性注射的PV-Cre绒猴的皮质区域（Feng） 结构可以在类似的灵长类动物的注意力、认知灵活性和 在MIT的偏好行为我们的集体工作将决定生物决定因素 感觉系统中的关键期在认知中起着类似的作用，相应的回路 当Shank 3/Mecp 2症状逆转时纠正的变化以及 小鼠和灵长类动物的大脑不同。

Abstract Mice – with their short gestation time, lifespan, large litter size, and above all, genetic tractability –are powerful experimental tools with which to explore mammalian brain development. One striking example is the reversible disruption of autism risk genes, like Mecp2 or Shank3. Switching on these genes after the emergence of fullblown phenotypes rescues several motor- related symptoms, including inertia, abnormal gait, weight, irregular breathing, repetitive grooming or hind-limb clasping. Instead, other neurological aspects are uncorrected in adulthood, such as anxiety or motor coordination. Of central relevance to human patients, it remains unknown to what extent higher cognition is impaired in Shank3 or Mecp2 mutant mice and whether recovery would also be limited to a critical period. The Hensch project will directly address sensitive periods and reversibility of dorsomedial prefrontal cortical (dmPFC) functions using novel behavioral tests of attention, cognitive flexibility and acoustic preference along with associated physiological measures from relevant areas. Pioneering work in the first phase of the Conte Center established the pivotal role of particular inhibitory neurons underlying critical period timing in mouse sensory systems. Parvalbumin (PV+) GABA circuit maturation dictates both the onset and closure of these windows of circuit refinement. Manipulations of psychiatric risk factors, such as circadian Clock gene disruption or redox dysregulation, can delay or extend developmental trajectories by upsetting the vulnerable PV+ component of local circuit excitatory-inhibitory balance. Recently, Hensch and Feng extended this principle to higher-order multi-sensory integration (MSI, commonly impaired in patients with autism) in the insular cortex. Shared MSI impairments in mice lacking either Shank3 (weak PV+) or Mecp2 (excessive PV+) suggest an optimal range of PV+ network function enables proper pruning of connections in the insula. Here, we will examine circuit physiology and anatomy before/after restoration of Shank3 or Mecp2 in mice, ultimately by full 3D EM circuit reconstruction with Lichtman also in marmosets carrying the same Shank3 deletion (from Feng). Further, our touchscreen two- choice visual attention assay, a multiple-choice foraging task to assess flexible rule learning, and preference for acoustic stimuli (music, ultrasonic calls) experienced early in life will probe dmPFC function in mutant and rescued mice. Electrophysiological recording and two-photon Calcium / Chloride imaging from the dmPFC in vivo will focus on PV+ networks in these areas across development, starting with comparison to Arlotta’s human organoids. Based on these many insights from mice, the impact of silencing/activating PV+ circuits in corresponding frontal cortical regions of PV-Cre marmosets (by Feng) using focal injections of viral DREADD constructs can be tested on analogous primate tasks of attention, cognitive flexibility and preference behavior at MIT. Our collective work will determine whether biological determinants of critical periods in sensory systems play a similar role in cognition, the corresponding circuit changes which are corrected when Shank3/Mecp2 symptoms are reversed and how much the mouse and primate brain differ.