Limbic Circuit Dysfunction in Offspring following Maternal Immune Activation

项目总结/摘要 在一般人群中，只有不到1%的儿童会发生癫痫发作，而超过30%的自闭症儿童 谱系障碍（ASD）在青春期就这样了。孕妇在怀孕期间感染是一个危险因素， ASD和癫痫，然而，我们对早期免疫损伤如何改变神经功能的理解有限。 与这两种疾病有关的回路内侧前额叶皮层（mPFC）是一个重要的大脑区域， 调节ASD中改变的各种认知和情感行为。我们已经获得了试验数据， 妊娠期暴露于病毒模拟物聚肌苷酸：聚胞苷酸后mPFC回路功能改变 （聚（I：C））。在急性mPFC脑切片中使用高通量多位点场电位记录方法， 初步结果表明，母体免疫激活（MIA）导致mPFC的持续改变 活动，在突触前和突触后位点，并增加易感性产生癫痫 体外活动拟议的实验将阐明精确的细胞类型和层特异性改变 网络兴奋性的潜在变化。本提案的目标1将确定功能性皮质内 mPFC内的连接。妊娠母鼠将接受生理盐水或聚（I：C）治疗，以获得急性抗病毒药物 炎症反应。含有mPFC的急性脑切片将从三岁到四岁的成年后代制备。 四个月大基于图案化谷氨酸释放的激光扫描光刺激将用于 映射光激发突触前神经元之间的mPFC内的兴奋性突触连接， 单个突触后锥体和中间神经元。对兴奋性和兴奋性的板层特异性输入的变化 MIA后的抑制细胞类型将通过突触的细胞内电压钳记录来评估。 活动免疫组织化学方法将确认细胞类型、位置和形态，并将用于 识别层压中的结构缺陷。目的2将评价远端输入的募集变化， 来自两个区域的mPFC高度参与边缘系统癫痫发作的启动和扩散，基底外侧 杏仁核（BLA）和腹侧海马（vHC）。将使用AAV-CamKII AAV-ChR 2/eYFP靶向表达 的通道视紫红质-eYFP或单独的eYFP的兴奋性神经元在这些额外的前额叶结构。 将测量L2/3和L5神经元中的mPFC中的突触后电流以响应光遗传学激活 BLA和vHC终端，分别和兴奋性和抑制性成分的变化进行评估。 这些目标共同解决电路内在和外在的变化，可能有助于共享 ASD和癫痫的发病机制。从一个mPFC电路的询问中获得的信息， 建立的MIA模型将鉴定可能作为治疗靶点的神经病理学改变。

PROJECT SUMMARY/ABSTRACT In the general population, less than 1% of children develop seizures, whereas over 30% of children with autism spectrum disorder (ASD) do so by adolescence. Maternal infection during pregnancy is a risk factor for both ASD and epilepsy, however we have limited understanding of how early-life immune insults alter neural circuitry implicated in both disorders. The medial prefrontal cortex (mPFC) is a brain region important for regulating diverse cognitive and emotional behaviors altered in ASD. We have obtained pilot data supporting altered mPFC circuit function after gestational exposure to a viral mimetic polyinosinic:polycytidylic acid (poly(I:C)). Using a high-throughput multisite field potential recording approach in acute mPFC brain slices, our preliminary results indicate that maternal immune activation (MIA) leads to persistent alterations in mPFC activity, at both presynaptic and postsynaptic loci, and an increased susceptibility to generation of epileptic activities in vitro. The proposed experiments will elucidate the precise cell type- and lamina-specific alterations underlying changes in network excitability. Aim 1 of this proposal will identify changes to functional intracortical connectivity within the mPFC. Pregnant dams will be treated with saline or poly(I:C) to mount an acute antiviral inflammatory response. Acute brain slices containing mPFC will be prepared from adult offspring at three to four months of age. Laser scanning photostimulation based on patterned glutamate uncaging will be used to map excitatory synaptic connectivity within the mPFC between photo-excited presynaptic neurons and individual postsynaptic pyramidal and interneurons. Changes to laminar-specific inputs to excitatory and inhibitory cells types following MIA will be assessed by intracellular voltage-clamp recordings of synaptic activity. Immunohistochemical methods will confirm cell type, location and morphology and will be used to identify structural defects in lamination. Aim 2 will evaluate alterations in the recruitment of distal inputs to the mPFC from two regions highly implicated in the initiation and spread of limbic seizures, the basolateral amygdala (BLA) and ventral hippocampus (vHC). AAV-CamKII-ChR2/eYFP will be used to target expression of channelrhodopsin-eYFP or eYFP alone to excitatory neurons in these extra-prefrontal structures. Postsynaptic currents in mPFC in L2/3 and L5 neurons will be measured in response to optogenetic activation of BLA and vHC terminals, respectively, and changes in excitatory and inhibitory components assessed. Together these aims address circuit intrinsic and extrinsic changes that may contribute to the shared pathogenesis of ASD and epilepsy. Information gained from the interrogation of mPFC circuitry in an established MIA model will identify neuropathological alterations that might be targeted for therapies.