The somatosensory system decodes a range of tactile stimuli to generate a coherent sense of touch. Discriminative touch of the body depends on signals conveyed from peripheral mechanoreceptors to the brain through the spinal cord dorsal column and its brainstem target, the dorsal column nuclei (DCN)^1,2. Models of somatosensation emphasize that fast-conducting low-threshold mechanoreceptors (LTMRs) innervating the skin drive the DCN^3,4. However, postsynaptic dorsal column (PSDC) neurons within the spinal cord dorsal horn also collect mechanoreceptor signals and form a second major input to the DCN^5,6,7. The significance of PSDC neurons and their contributions to the coding of touch have remained unclear since their discovery. Here we show that direct LTMR input to the DCN conveys vibrotactile stimuli with high temporal precision. Conversely, PSDC neurons primarily encode touch onset and the intensity of sustained contact into the high-force range. LTMR and PSDC signals topographically realign in the DCN to preserve precise spatial detail. Different DCN neuron subtypes have specialized responses that are generated by distinct combinations of LTMR and PSDC inputs. Thus, LTMR and PSDC subdivisions of the dorsal column encode different tactile features and differentially converge in the DCN to generate specific ascending sensory processing streams.

体感系统解码一系列触觉刺激以产生连贯的触觉。身体的辨别性触摸取决于从外周机械感受器通过脊髓背柱及其脑干目标背柱核 (DCN) 传递到大脑的信号^1,2。体感模型强调支配皮肤的快速传导低阈值机械感受器 (LTMR) 驱动 DCN ^3,4。然而，脊髓背角内的突触后背柱 (PSDC) 神经元也收集机械感受器信号并形成 DCN 的第二个主要输入^5,6,7。自发现以来，PSDC 神经元的重要性及其对触觉编码的贡献仍不清楚。在这里，我们表明直接 LTMR 输入到 DCN 可以以高时间精度传达振动触觉刺激。相反，PSDC 神经元主要将触摸开始和持续接触的强度编码为高力范围。LTMR 和 PSDC 信号在 DCN 中进行拓扑重新排列，以保留精确的空间细节。不同的 DCN 神经元亚型具有由 LTMR 和 PSDC 输入的不同组合生成的专门响应。因此，背柱的 LTMR 和 PSDC 细分编码不同的触觉特征，并在 DCN 中差异性地汇聚，以生成特定的上升感觉处理流。