Striosome Microcircuit Critical for Motor Skill Learning

纹状体微电路对于运动技能学习至关重要

• 批准号: 10688882
• 负责人: Huaibin Cai
• 金额: $ 21.23万
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10688882
• 关键词: Axon; Calcium; Control Groups; Corpus striatum structure; Dendrimers; Dendrites; Dopamine; Dorsal; Electrophysiology (science); Enterobacteria phage P1 Cre recombinase; Feedback; Fiber; Fiber Optics; GABA-B Receptor; Genetic; Globus Pallidus; Implant; LRRK2 gene; Learning; Motor Skills; Mus; Neurons; Pathway interactions; Pattern; Performance; Photometry; Physiological; Play; Presynaptic Terminals; Process; Regulation; Role; Rotarod Performance Test; Signal Transduction; Structure; Thinness; Time; Training; Transgenic Mice; Viral Vector; base; calcium indicator; designer receptors exclusively activated by designer drugs; improved; motor control; motor impairment; motor learning; motor skill learning; mouse model; nerve supply; neural; optogenetics; presynaptic; protein biomarkers; response; selective expression; striosome

Since ALDH1A1+ SNc DANs are required for rotarod motor skill learning and striosome dSPNs provide major inhibitory presynaptic inputs and regulate the transition from tonic to burst firing of ALDH1A1+ SNc DANs, we decided to systematically examine the involvement of striosome dSPNs in motor skill leaning. To elucidate how striosome dSPNs participate in motor skill learning, we first performed fiber photometry live recording of striosome neural activity during 10 sequential rotarod training sessions. We injected Cre-dependent GCaMP6-axon and tdTomato viral vectors to the dorsal striatum of Sepw1-Cre mice (a transgenic mouse model with preferential expression of Cre recombinase in striosomes), which allows for selective expression of this genetically encoded calcium indicator in the axon terminals of striosome neurons. Then we implanted an optic fiber in SNr to record calcium transients specifically in the axon terminals of striosome dSPNs during the rotarod tests. In contrast to the fast improvement of rotarod performance, our fiber photometry recording revealed a large increase of presynaptic calcium transients in the first trial of the first training session, with calcium transients gradually decreasing in the subsequent nine trials. The same reverse correlation between rotarod performance and presynaptic calcium transients was also observed in the 10 trials of the second training sessions. The calcium transients diminished in the following four sessions. These observations suggest that the striosome dSPNs may promote a novelty or salience signal to initiate the motor learning process. Since striosomes are comprised with both dSPNs and indirect-pathway SPNs (iSPNs), and their axonal targets include SNr, globus pallidus internus (GPi), and globus pallidus externa (GPe), we will also record the presynaptic calcium transients in GPi and GPe regions during rotarod tests and reveal their activity patterns over different trials and sessions. To determine whether striosome SPNs are required for motor skill learning, we used chemogenetic approach to modulate the striosome neuronal activity during rotarod training sessions. We injected Cre-dependent Gq and Gi chemogenetic modulator DREADD, as well as control mCherry viral vectors to the dorsal striatum of Sepw1-Cre mice, to either activate (Gq) or inhibit (Gi) the striosome neuronal activity during motor skill learning. We found that inhibition of striosome neuronal activity completely disrupted the motor skill learning, whereas activation of striosome neurons substantially improved the learning in Sepw1-Cre mice when compared with the mCherry control group. These findings demonstrated that striosome neurons are required for rotarod motor skill learning. To determine which striosome SPN subtype(s) plays a role in motor skill learning, we will use an optogenetics approach to selectively inhibit the transmitter release in the corresponding axon terminals at SNr, GPe and GPi during rotarod training. Together, this combination of fiber photometry, chemogenetics and opogenetics approaches will help to establish a causal relationship between the activity of striosome SPN subtypes and motor skill learning. To determine whether the strisosome dSPN-induced rebound and burst firing in ALDH1A1+ SNc DANs is related to motor skill learning, we will conduct fiber photometry recording of calcium transients in the axon terminals of strisosome dSPNs and single unit electrophysiology recording of ALDH1A1+ SNc DANs simultaneously during rotarod training sessions. We will investigate whether genetic deletion of GABA-B receptors in ALDH1A1+ SNc DANs disrupts the dSPN-induced rebound and burst firing and impairs motor skill learning. This study will help to define a key physiological function of striosome dSPN and ALDH1A1+ SNc DAN microcircuit in regulating motor learning.

由于 ALDH1A1+ SNc DAN 是旋转运动技能学习所必需的，并且纹状体 dSPN 提供主要的抑制性突触前输入并调节 ALDH1A1+ SNc DAN 从强直到爆发放电的转变，因此我们决定系统地研究纹状体 dSPN 在运动技能学习中的参与。 为了阐明纹状体 dSPN 如何参与运动技能学习，我们首先在 10 次连续旋转训练期间对纹状体神经活动进行光纤光度测定实时记录。我们将 Cre 依赖性 GCaMP6-axon 和 tdTomato 病毒载体注射到 Sepw1-Cre 小鼠（一种在纹状体中优先表达 Cre 重组酶的转基因小鼠模型）的背侧纹状体中，从而允许在轴突中选择性表达这种遗传编码的钙指示剂纹状体神经元的末端。然后，我们在 SNr 中植入光纤，以记录旋转杆测试期间纹状体 dSPN 轴突末端的钙瞬变。与旋转杆性能的快速提高相反，我们的纤维光度测量记录显示，在第一次训练的第一次试验中，突触前钙瞬变大量增加，而在随后的九次试验中，钙瞬变逐渐减少。在第二次训练的 10 次试验中，也观察到转棒表现与突触前钙瞬变之间存在相同的反向相关性。在接下来的四次治疗中，钙瞬变减少了。这些观察结果表明，纹状体 dSPN 可能会促进新奇或显着信号来启动运动学习过程。由于纹状体由 dSPN 和间接通路 SPN (iSPN) 组成，并且它们的轴突靶标包括 SNr、苍白球内部 (GPi) 和苍白球外部 (GPe)，因此我们还将记录 GPi 和 GPe 中的突触前钙瞬变旋转棒测试期间的区域并揭示它们在不同试验和会议中的活动模式。 为了确定运动技能学习是否需要纹状体 SPN，我们在转棒训练期间使用化学遗传学方法来调节纹状体神经元活动。我们将 Cre 依赖性 Gq 和 Gi 化学遗传学调节剂 DREADD 以及控制 mCherry 病毒载体注射到 Sepw1-Cre 小鼠的背侧纹状体，以在运动技能学习过程中激活 (Gq) 或抑制 (Gi) 纹状体神经元活动。我们发现，纹状体神经元活动的抑制完全破坏了运动技能的学习，而与 mCherry 对照组相比，纹状体神经元的激活显着改善了 Sepw1-Cre 小鼠的学习能力。这些发现表明，纹状体神经元是旋转运动技能学习所必需的。为了确定哪些纹状体 SPN 亚型在运动技能学习中发挥作用，我们将使用光遗传学方法在转棒训练期间选择性抑制 SNr、GPe 和 GPi 相应轴突末端的递质释放。纤维光度测定法、化学遗传学和光遗传学方法的结合将有助于建立纹状体 SPN 亚型的活动与运动技能学习之间的因果关系。 为了确定 ALDH1A1+ SNc DAN 中纹小体 dSPN 诱导的反弹和爆发放电是否与运动技能学习有关，我们将同时进行纹小体 dSPN 轴突末端钙瞬变的纤维光度记录和 ALDH1A1+ SNc DAN 的单单元电生理学记录。转棒培训课程。我们将研究 ALDH1A1+ SNc DAN 中 GABA-B 受体的基因删除是否会破坏 dSPN 诱导的反弹和爆发放电并损害运动技能学习。这项研究将有助于确定纹状体 dSPN 和 ALDH1A1+ SNc DAN 微电路在调节运动学习中的关键生理功能。