Beyond labeled lines: A population coding account of the thermal grill illusion

TY - JOUR

T1 - Beyond labeled lines

T2 - A population coding account of the thermal grill illusion

AU - Fardo, Francesca

AU - Beck, Brianna

AU - Allen, Micah

AU - Finnerup, Nanna Brix

N1 - Copyright © 2019 Elsevier Ltd. All rights reserved.

PY - 2020/1

Y1 - 2020/1

N2 - Heat and pain illusions (synthetic heat and the thermal grill illusion) can be generated by simultaneous cold and warm stimulation on the skin at temperatures that would normally be perceived as innocuous in isolation. Historically, two key questions have dominated the literature: which specific pathway conveys the illusory perceptions of heat and pain, and where, specifically, does the illusory pain originate in the central nervous system? Two major theories - the addition and disinhibition theories - have suggested distinct pathways, as well as specific spinal or supraspinal mechanisms. However, both theories fail to fully explain experimental findings on illusory heat and pain phenomena. We suggest that the disagreement between previous theories and experimental evidence can be solved by abandoning the assumption of one-to-one relations between pathways and perceived qualities. We argue that a population coding framework, based on distributed activity across non-nociceptive and nociceptive pathways, offers a more powerful explanation of illusory heat and pain. This framework offers new hypotheses regarding the neural mechanisms underlying temperature and pain perception.

AB - Heat and pain illusions (synthetic heat and the thermal grill illusion) can be generated by simultaneous cold and warm stimulation on the skin at temperatures that would normally be perceived as innocuous in isolation. Historically, two key questions have dominated the literature: which specific pathway conveys the illusory perceptions of heat and pain, and where, specifically, does the illusory pain originate in the central nervous system? Two major theories - the addition and disinhibition theories - have suggested distinct pathways, as well as specific spinal or supraspinal mechanisms. However, both theories fail to fully explain experimental findings on illusory heat and pain phenomena. We suggest that the disagreement between previous theories and experimental evidence can be solved by abandoning the assumption of one-to-one relations between pathways and perceived qualities. We argue that a population coding framework, based on distributed activity across non-nociceptive and nociceptive pathways, offers a more powerful explanation of illusory heat and pain. This framework offers new hypotheses regarding the neural mechanisms underlying temperature and pain perception.

KW - Illusion

KW - Pain

KW - Synthetic heat

KW - TGI

KW - Thermal grill

KW - Thermosensation

U2 - 10.1016/j.neubiorev.2019.11.017

DO - 10.1016/j.neubiorev.2019.11.017

M3 - Review

C2 - 31783059

SN - 0149-7634

VL - 108

SP - 472

EP - 479

JO - Neuroscience and Biobehavioral Reviews

JF - Neuroscience and Biobehavioral Reviews

ER -