Supplementary Figure 6: Additional characterization of Aβ inputs and outputs in VT3^Cre-tdTomato⁺ neurons

(a) Schematics illustrate how to prepare sagittal spinal cord slices to preserve low-threshold Aβ-fiber inputs onto dorsal horn neurons, based on the relative positions of the second cut to the entrance region of the dorsal root. (b) Low threshold Aβ intensity stimulation-induced inputs/outputs in a type 1 VT3^Cre-tdTomato⁺ neuron, indicating receiving Aβ with feedforward inhibition. Black arrows indicate artifacts. Red arrows indicate eEPSC/eEPSP and black arrowheads indicate eIPSC/eIPSP. The recordings are composed of three repeated traces. (c) Summary of low threshold Aβ intensity-induced inputs/outputs in VT3^Cre-tdTomato⁺ neuron in different laminae under normal recording conditions. Most VT3^Cre-tdTomato⁺ neurons that received Aβ evoked-EPSCs under normal recording conditions also received eIPSCs, indicating feedforward inhibition. (d) Summary of low threshold Aβ intensity-induced inputs/outputs in VT3^Cre-tdTomato⁺ neurons under both control and disinhibition conditions, with or without APV, a NMDAR antagonist (see recording traces in Fig. 5a-c). (e) Schematics showing primary afferent inputs to VT3^Cre-tdTomato⁺ neurons. “V1” and “V2” represent type 1 and type 2 neurons, respectively. “In” represents inhibitory interneurons. “V1?” indicates a type 1 VT3^Cre-tdTomato⁺ neuron or a V1-like neuron not marked by VT3^Cre. (f) Percentages of type1 and type 2 VT3^Cre-tdTomato⁺ neurons that displayed distinct firing patterns following current injection.