Spatial integration of cold pressor pain sensation in humans.
Spatial integration of cold pressor pain (CPP) in the hand was studied in healthy human subjects by measuring the latency to the ice water-induced first pain sensation with and without conditioning CPP. CPP alone showed a marked spatial summation effect. When conditioning and test CPP were applied at the same time, conditioning CPP suppressed test CPP both in an adjacent and a distant site. When test CPP was applied after the conditioning CPP (i.e. pain induced by conditioning CPP was considerably stronger than that evoked by test CPP) conditioning CPP suppressed the test CPP only in a distant site but enhanced it in an adjacent site. A decrease in the test stimulus area increased the suppressive effect by conditioning CPP. Thus, CPP shows spatial summation or inhibition depending on experimental parameters.
Martikainen
Ilkka K
IK
Department of Physiology, Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland.
Närhi
Matti V
MV
Pertovaara
Antti
A
D000328:Adult; D000344:Afferent Pathways / Q000502:physiology*; D001808:Blood Vessels / Q000294:innervation / Q000502:physiology; D002490:Central Nervous System / Q000502:physiology; D003080:Cold Temperature / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D017288:Pain Threshold / Q000502:physiology; D010812:Physical Stimulation; D011930:Reaction Time / Q000502:physiology; D012867:Skin / Q000294:innervation*; D009435:Synaptic Transmission / Q000502:physiology