Detection of temperature increases in the operating range of warm receptors and of nociceptors

Abstract

In healthy subjects the ability to detect small temperature increases in a 2-alternative forced choice experiment was tested from different basic temperatures ranging from 36-46.degree. C. Detection improved up to an adapting temperature (AT) of 40.degree. C, a further increase of AT into the operating range of nociceptors did not change detection rate. The subjects rated their confidence after each forced choice on a 6-point scale. From these confidence ratings, 2 measures developed in the context of sensory decision theory were calculated, one of discrimination and one of bias. A bias towards higher confidence in having detected temperature increases was the clearest sign of transition into the operating range of nociceptors.