(A) Schematic of the semi-intact somatosensory preparation. Spinal cord, L2 and L3 roots, saphenous nerve, lateral femoral cutaneous nerve, and hind paw skin are taken together and whole-cell patch clamp recording is made from retrogradely-labeled SPB neurons. (B) Pie chart of response properties of SPB neurons to mechanical (small, firm brush and/or von Frey filaments, 1 – 4 g), cold (0˚C saline) and heat (50 ˚C saline) stimulation to the skin. Approximately 25% of SPB neurons are cold-selective. n = 34 SPB neurons from 22 mice. (C-H) Example traces of a cold-selective SPB neuron (C), a mechano-selective neuron (D) a mechano- and cold-sensitive neuron (E), a mechano- and heat-sensitive neuron (F), a mechano- heat- and cold-sensitive neuron (G), and a subthreshold neuron, which showed EPSPs but no action potentials. * indicates response to stimulation is greater than 3 SD of the baseline activity.