Figure 1. Schematic representation of two variations of the computational model: (a) Model variation A involving an integrated cortical map receiving input from both tactile and nociceptive channels.

(b) Model variation B involving a split cortical map receiving separate input from tactile and nociceptive channels. The tactile and nociceptive channels (red and blue lines) sample the entire skin surface. For simplicity, a homogeneous distribution of receptors was assumed, and only the fingers of one hand were modeled. Each channel has a receptive field on the skin with a specific threshold and gain for either tactile or nociceptive stimuli. There are three types of gate per channel: peripheral gates, spinal gates, and central gates. The peripheral gates control the receptor sensitivity, the spinal gates control the afferent flow through the dorsal horn, and the central gates control the input into a self-organizing cortical map. Each channel is independently afflicted with discrete neuronal noise (DNN) and spontaneous coherent activity (SCA). For the simulations, the only modified parameters after amputation correspond to the channels originating in the amputated finger. These are 1) the spinal gate threshold, 2) the SCA strength, and 3) the central gate threshold. See Table 1 for an overview over the model parameters on the different conditions.