Spatial discrimination of one versus two test stimuli in the human skin: dissociation of mechanisms depending on the task and the modality of stimulation.
We determined whether the ability to localize a single noxious cold versus innocuous tactile stimulus is associated with the ability to discriminate between two stimuli in the forearm skin of healthy human subjects. When single stimuli were applied, the localization of a noxious cold stimulus was at least as good as that of a tactile stimulus. With both of these modalities, the localization of a single stimulus was more accurate in the radial-ulnar than proximo-distal direction. In contrast to localization of a single stimulus, the discrimination of two cutaneous test stimuli from each other was an order of magnitude worse for noxious cold than touch. This dissociation indicates that localization of single cutaneous stimuli and discrimination of two cutaneous stimuli from each other are based on different mechanisms.
Martikainen
Ilkka K
IK
Department of Physiology, Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, 20520, Turku, Finland.
Pertovaara
Antti
A
D000328:Adult; D003080:Cold Temperature; D004056:Differential Threshold; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000379:methods; D012879:Skin Physiological Phenomena; D013028:Space Perception / Q000502:physiology*; D014110:Touch