The encoding of thermal stimuli by diffuse noxious inhibitory controls (DNIC).

The relationship between stimulus intensity and its efficacy in inducing diffuse noxious inhibitory controls (DNIC) was investigated in anaesthetized rats by using thermal stimulation of the tail for conditioning dorsal horn convergent neuronal responses to C fibres emanating from the hindpaw extremity. The threshold for obtaining inhibition of the neuronal responses ranged between 40 and 44 degrees C and there was a highly significant correlation between noxious temperatures (44-52 degrees C) and the degree of inhibition. These data provide support for the notion of an involvement of inhibitory processes (DNIC) in the signalling of pain by convergent neurones.