Figure 3. The measured thermal stimulus traces applied on the surface of the skin with three ramp rates and the estimated stimulus traces within the skin at the estimated depth of neurons’ terminals for two example neurons C-MH1 and C-MH4.

The estimation of the depth and T_threshold was done according to the classical and probabilistic method. The probabilistic estimated T_threshold is the solution of equation (3). The classical T_threshold is the intersection of Tⁱ_surface, i = 1,2,3 curves in D-T_threshold plane for three ramp rates of equation (1). (a–c) The stimulus traces of neuron C-MH1 for (a) long ramp, (b) middle ramp, and (c) short ramp. Both classical and probabilistic methods successfully estimated the parameters. The classical model approached a single intersection of ramped stimuli and probabilistic method approached small delays. (d–f) The stimulus traces of neuron C-MH4 for (d) long ramp, (e) middle ramp, and (f) short ramp. The classical method failed to find an intersection but the probabilistic method resulted successfully to a parameters estimate.