The rodent external globus pallidus (GPe) contains two main neuronal subpopulations, prototypic and arkypallidal cells, which differ in their cellular properties. Their functional synaptic connectivity is largely unknown. Here we studied the membrane properties, synaptic inputs, and sensory responses of these subpopulations in the mouse GPe. We performed in vivo whole-cell recordings in GPe neurons and used optogenetic stimulation to dissect their afferent inputs from the striatum and subthalamic nucleus (STN). Both GPe subpopulations received barrages of excitatory and inhibitory inputs during slow wave activity and responded to sensory stimulation with distinct multiphasic patterns. Prototypic cells synaptically inhibited arkypallidal and prototypic cells. Both GPe subpopulations received synaptic input from STN and striatal medium spiny neurons (MSNs). Although STN and indirect pathway MSNs strongly targeted prototypic cells, direct pathway MSNs selectively inhibited arkypallidal cells. We show that GPe subtypes have distinct connectivity patterns that underlie their respective functional roles.

啮齿动物外部苍白球（GPe）包含两个主要的神经元亚群，即原型和侧苍白细胞，它们的细胞特性不同。它们的功能性突触连通性很大程度上未知。在这里，我们研究了小鼠GPe中这些亚群的膜特性，突触输入和感觉响应。我们在体内进行GPe神经元中的全细胞记录，并使用光遗传学刺激从纹状体和丘脑下核（STN）解剖其传入输入。这两个GPe亚群在慢波活动期间均收到大量的兴奋性和抑制性输入，并以明显的多相模式对感觉刺激做出反应。原型细胞突触地抑制了腮腺细胞和原型细胞。这两个GPe亚群均从STN和纹状体中棘神经元（MSN）接收突触输入。尽管STN和间接途径的MSN强烈靶向原型细胞，但直接途径的MSN选择性地抑制了腮腺细胞。我们显示GPe子类型具有不同的连通性模式，这些模式是其各自功能角色的基础。