Perceiving substrate-borne vibrations is a fundamental component of tactile perception. How location (somatotopy) and frequency tuning (tonotopy) of vibrations are integratively processed is poorly understood. Here we addressed this question using in vivo electrophysiology and two-photon calcium imaging along the dorsal column–medial lemniscal pathway. We found that both frequency and location are organized into structured maps in the dorsal column nuclei (DCN). Both maps are intimately related at the fine spatial scale, with parallel map gradients that are consistent across the depth of the DCN and preserved along the ascending pathway. The tonotopic map only partially reflects the distribution of end organs in the skin and deep tissue; instead, the emergence of the fine-scale tonotopy is due to the selective dendritic sampling from axonal afferents, already at the first synaptic relay. We conclude that DCN neural circuits are key to the emergence of these two fine-scale topographical organizations in early somatosensory pathways.

感知基板传播的振动是触觉感知的基本组成部分。人们对振动的位置（体位）和频率调谐（音调）是如何被综合处理的知之甚少。在这里，我们使用体内电生理学和沿背柱-内侧 lemniscal 通路的双光子钙成像来解决这个问题。我们发现频率和位置都组织成背柱核 （DCN） 中的结构化图。两张地图在精细的空间尺度上密切相关，平行地图梯度在 DCN 的深度上保持一致，并沿上升路径保留。音调图仅部分反映了皮肤和深层组织中终末器官的分布;相反，精细尺度音调的出现是由于来自轴突传入神经的选择性树突采样，已经在第一次突触中继处。我们得出结论，DCN 神经回路是早期体感通路中出现这两个精细地形组织的关键。