Somatosensation encompasses a variety of essential modalities including touch, pressure, proprioception, temperature, pain, and itch. These peripheral sensations are crucial for all types of behaviors, ranging from social interaction to danger avoidance. Somatosensory information is transmitted from primary afferent fibers in the periphery into the central nervous system via the dorsal horn of the spinal cord. The dorsal horn functions as an intermediary processing center for this information, comprising a complex network of excitatory and inhibitory interneurons as well as projection neurons that transmit the processed somatosensory information from the spinal cord to the brain. It is now known that there can be dysfunction within this spinal cord circuitry in pathological pain conditions and that these perturbations contribute to the development and maintenance of pathological pain. However, the complex and heterogeneous network of the spinal dorsal horn has hampered efforts to further elucidate its role in somatosensory processing. Emerging optical techniques promise to illuminate the underlying organization and function of the dorsal horn and provide insights into the role of spinal cord sensory processing in shaping the behavioral response to somatosensory input that we ultimately observe. This review article will focus on recent advances in optogenetics and fluorescence imaging techniques in the spinal cord, encompassing findings from both in vivo and in vitro preparations. We will also discuss the current limitations and difficulties of employing these techniques to interrogate the spinal cord and current practices and approaches to overcome these challenges.

中文翻译：

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使用光学方法洞察脊髓背角电路功能和功能障碍。

躯体感觉包括多种基本方式，包括触觉，压力，本体感受，温度，疼痛和瘙痒。这些外围感觉对于从社交互动到危险规避的所有行为都是至关重要的。体感信息从周围的初级传入纤维通过脊髓的背角传递到中枢神经系统。背角充当该信息的中间处理中心，包括兴奋性和抑制性中间神经元以及投射神经元的复杂网络，这些神经元将经过处理的体感信息从脊髓传递到大脑。现在已知在病理性疼痛情况下该脊髓电路中可能存在功能障碍，并且这些扰动有助于病理性疼痛的发展和维持。但是，脊髓背角复杂而异质的网络阻碍了进一步阐明其在体感加工中的作用的努力。新兴的光学技术有望阐明背角的基本组织和功能，并深入了解脊髓感觉处理在塑造我们最终观察到的对体感输入的行为反应中的作用。这篇综述文章将重点介绍脊髓光遗传学和荧光成像技术的最新进展，包括体内和体外制剂的发现。