Waitt Advanced Biophotonics Center, The Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
Electrical and Computer Engineering Graduate Program, University of California, San Diego, La Jolla, CA, 92037, USA.
Nat Commun. 2023 Mar 21;14(1):1427. doi: 10.1038/s41467-023-36959-2.
While the spinal cord is known to play critical roles in sensorimotor processing, including pain-related signaling, corresponding activity patterns in genetically defined cell types across spinal laminae have remained challenging to investigate. Calcium imaging has enabled cellular activity measurements in behaving rodents but is currently limited to superficial regions. Here, using chronically implanted microprisms, we imaged sensory and motor-evoked activity in regions and at speeds inaccessible by other high-resolution imaging techniques. To enable translaminar imaging in freely behaving animals through implanted microprisms, we additionally developed wearable microscopes with custom-compound microlenses. This system addresses multiple challenges of previous wearable microscopes, including their limited working distance, resolution, contrast, and achromatic range. Using this system, we show that dorsal horn astrocytes in behaving mice show sensorimotor program-dependent and lamina-specific calcium excitation. Additionally, we show that tachykinin precursor 1 (Tac1)-expressing neurons exhibit translaminar activity to acute mechanical pain but not locomotion.
脊髓在感觉运动处理中起着关键作用，包括与疼痛相关的信号传递，但在遗传定义的细胞类型中，相应的活动模式在脊髓板层中仍然难以研究。钙成像技术能够在行为活跃的啮齿动物中进行细胞活动测量，但目前仅限于浅层区域。在这里，我们使用慢性植入的微棱镜，在以前的高分辨率成像技术无法到达的区域和速度下，对感觉和运动诱发的活动进行成像。为了使通过植入微棱镜在自由活动的动物中实现跨板层成像，我们还开发了带有定制复合微透镜的可穿戴显微镜。该系统解决了以前可穿戴显微镜的多个挑战，包括其有限的工作距离、分辨率、对比度和消色差范围。使用该系统，我们表明在行为活跃的小鼠中，背角星形胶质细胞表现出感觉运动程序依赖性和板层特异性钙兴奋。此外，我们还表明，速激肽前体 1（Tac1）表达神经元表现出对急性机械性疼痛的跨板层活动，但对运动没有反应。
