Fuster Laboratory of Cognitive Neuroscience, Department of Psychiatry and Biobehavioral Sciences, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA.
Cell Rep. 2022 Apr 19;39(3):110699. doi: 10.1016/j.celrep.2022.110699.
We report that increasing inhibition from the basal ganglia (BG) to the superior colliculus (SC) through the substantia nigra pars reticulata (nigra) using in vivo optogenetic activation of GABAergic terminals in mice produces contralateral orienting movements. These movements are unexpected because decreases, and not increases, in nigral activity are generally associated with the initiation of orienting movements. We found that, in slice recordings, the same optogenetic stimulation of nigral terminals producing movements in vivo evokes post-inhibitory rebound depolarization followed by Na spikes in SC output neurons. Moreover, blocking T-type Ca channels in slices prevent post-inhibitory rebound and subsequent Na spiking in SC output neurons and also reduce the likelihood of contralateral orienting in vivo. On the basis of these results, we propose that, in addition to the permissive role, the BG may play an active role in the generation of orienting movements in mice by driving post-inhibitory rebound depolarization in SC output neurons.
我们报告称，通过在体内使用光遗传学方法激活小鼠黑质网状部（nigra）中的 GABA 能末梢，增加基底神经节（BG）对上丘（SC）的抑制作用，会产生对侧定向运动。这些运动出乎意料，因为通常情况下，黑质活动的减少而不是增加与定向运动的启动有关。我们发现，在切片记录中，对体内产生运动的相同黑质末梢进行光遗传学刺激会引起 SC 输出神经元的后抑制性反弹去极化，随后是 Na 峰。此外，在切片中阻断 T 型钙通道会防止 SC 输出神经元中的后抑制性反弹和随后的 Na 峰，并降低体内对侧定向的可能性。基于这些结果，我们提出，除了许可作用之外，BG 可能通过驱动 SC 输出神经元中的后抑制性反弹去极化，在小鼠定向运动的产生中发挥积极作用。
