Fig. 1. Typical examples of an abrupt (left ) and a sustained (right ) neuron. Peristimulus–time histograms (1-s bins) are displayed, demonstrating response to colorectal distension (CRD; 80 mmHg, 20 s). Convergent cutaneous receptive fields for the same neurons are displayed in adjacent cartoon form. Brushing of the skin, pinching with forceps, and applying a hot probe (> 50°C) were used as cutaneous stimuli:+= excitatory response; −= inhibitory response; o = no response.