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

Fardo, Francesca; Beck, Brianna; Allen, Micah; Finnerup, Nanna Brix

doi:10.1016/j.neubiorev.2019.11.017

Cited by 23 publications

(29 citation statements)

References 84 publications

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“…48 Population coding, in which sensory quality depends on a balance of activity across many different afferents, potentially differing in physiological type as well as in location, may play a crucial role in robust and stable thermosensation. 49 In the thermal system, spatial summation is a well-known feature in both object-level perception and in thermoregulation. 50,51 In our study, we use small probes to study thermosensation in its role during object-level perception.…”

Section: Discussionmentioning

confidence: 99%

Revisiting a classical theory of sensory specificity: assessing consistency and stability of thermosensitive spots

Ezquerra-Romano¹,

Clements

Costa³

et al. 2023

Preprint

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Thermal sensitivity is not uniform across the skin, and is particularly high in small (~1mm2) regions termed 'thermosensitive spots'. These spots are thought to reflect the anatomical location of specialised thermosensitive nerve endings from single primary afferents. Thermosensitive spots provide foundational support for 'labelled line' or specificity theory of sensory perception, which state that different sensory qualities are transmitted by separate and specific neural pathways. This theory predicts a highly stable relation between repetitions of a thermal stimulus and the resulting sensory quality, yet these predictions have rarely been tested systematically. Here we present the qualitative, spatial and repeatability properties of 334 thermosensitive spots on the dorsal forearm sampled across 4 separate sessions. In line with previous literature, we found that spots associated with cold sensations (112 cold spots, 34%) were more frequent than spots associated with warm sensations (41 warm spots, 12%). Still more frequent (165 spots, 49%) were spots that elicited inconsistent sensations when repeatedly stimulated by the same temperature. Remarkably, only 13 spots (4%) conserved their position between sessions. Overall, we show unexpected inconsistency of both the perceptual responses elicited by spot stimulation and of spot locations across time. These observations challenge the traditional view that thermosensitive spots reflect the location of individual thermosensitive primary afferents serving as specific labelled lines for corresponding sensory qualities.

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Section: Discussionmentioning

confidence: 99%

Revisiting a classical theory of sensory specificity: assessing consistency and stability of thermosensitive spots

Ezquerra-Romano¹,

Clements

Costa³

et al. 2023

Preprint

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“…Provided that these interlaced bars are suitably arranged, and their temperature differs by a sufficiently large margin (roughly ≥20°C), bars whose independent application is perceived as painless are collectively perceived as producing a painful burning sensation (Alrutz, 1898; Thunberg, 1896). While there is disagreement as to why this should be, candidate accounts suggest that it involves pain processing making a kind of (inferential) error about the nature, source or significance of the sensory stimulation it receives as input (Fardo et al, 2020). Yet what is known or believed by the organism seems to have no clear effect on the underlying systems' assessment of the situation.…”

Section: Modularity As the Default Hypothesismentioning

confidence: 99%

“…For example, onset of acute pain is frequently delayed by minutes, if not days (Melzack et al, 1982; Wall, 1979), while pain following a stroke or spinal cord injury can take years to set in (Schott, 2001). Even pain onset in the TGI is typically delayed by several seconds (Fardo et al, 2020). Consequently, one's cognitive assessment of an injury (or lack thereof) often precedes pain onset by a significant margin.…”

Section: Modularity As the Default Hypothesismentioning

confidence: 99%

Is pain modular?

Clarke

2022

Mind & Language

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We suggest that pain processing has a modular architecture. We begin by motivating the (widely assumed but seldom defended) conjecture that pain processing comprises inferential mechanisms. We then note that pain exhibits a characteristic form of judgement independence. On the assumption that pain processing is inferential, we argue that its judgement independence is indicative of modular (encapsulated) mechanisms. Indeed, we go further, suggesting that it renders the modularity of pain mechanisms a default hypothesis to be embraced pending convincing counterevidence. Finally, we consider what a modular pain architecture might look like, and question alleged counterevidence to our proposal.

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“…Two major theories on the development of the TGI have been suggested: the "addition or convergence theory" and "disinhibition or unmasking theory" [8][9][10][11][12].…”

Section: The Underlining Mechanisms Of the Tgimentioning

confidence: 99%

A Review on Various Topics on the Thermal Grill Illusion

Shin

Lee

2021

JCM

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The thermal grill illusion (TGI) is a paradoxical perception of burning heat and pain resulting from the simultaneous application of interlaced warm and cold stimuli to the skin. The TGI is considered a type of chronic centralized pain and has been used to apply nociceptive stimuli without inflicting harm to human participants in the study of pain mechanisms. In addition, the TGI is an interesting phenomenon for researchers, and various topics related to the TGI have been investigated in several studies, which we will review here. According to previous studies, the TGI is generated by supraspinal interactions. To evoke the TGI, cold and warm cutaneous stimuli should be applied within the same dermatome or across dermatomes corresponding to adjacent spinal segments, and a significant difference between cold and warm temperatures is necessary. In addition, due the presence of chronic pain, genetic factors, and sexual differences, the intensity of the TGI can differ. In addition, cold noxious stimulation, topical capsaicin, analgesics, self-touch, and the presence of psychological diseases can decrease the intensity of the TGI. Because the TGI corresponds to chronic centralized pain, we believe that the findings of previous studies can be applied to future studies to identify chronic pain mechanisms and clinical practice for pain management.

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

Abstract: The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record.

Cited by 23 publications

References 84 publications

Revisiting a classical theory of sensory specificity: assessing consistency and stability of thermosensitive spots

Revisiting a classical theory of sensory specificity: assessing consistency and stability of thermosensitive spots

Is pain modular?

A Review on Various Topics on the Thermal Grill Illusion

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