CO2 laser activation of nociceptive and non-nociceptive thermal afferents from hairy and glabrous skin

Towell, Anthony; Purves, A.M.; Boyd, Stewart

doi:10.1016/0304-3959(96)03016-3

Cited by 81 publications

(36 citation statements)

References 19 publications

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“…In addition, our early and late time windows correspond well to latencies of A␦ and C fiber-mediated cortical responses in previous electroencephalographic studies (9)(10)(11)(12)(13) and to reaction times to first and second pain of about 400-500 and 1,000 ms, respectively (1, 2, 4, 7). Taken together, these points strongly suggest that early and late responses reflect perception of first and second pain, respectively.…”

Section: Discussionsupporting

confidence: 86%

“…Neurophysiological recordings in humans revealed early A␦ fibermediated activations in S1, S2, and ACC (for review, see ref. 8), whereas C fiber-mediated cortical responses at latencies of about 1,000 ms have been shown in scalp recordings (9)(10)(11)(12)(13) but have not yet been consistently localized. Conversely, functional imaging studies using tonic C fiber stimuli demonstrated activation of S1, S2, Insula, and ACC (14-17) but did not provide temporal information.…”

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confidence: 99%

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Cortical representation of first and second pain sensation in humans

Ploner

Groß

Timmermann

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

204

109

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Single painful stimuli evoke two successive and qualitatively distinct sensations referred to as first and second pain sensation. Peripherally, the neural basis of this phenomenon is a dual pathway for pain with A␦ and C fibers mediating first and second pain, respectively. Yet, the differential cortical correlates of both sensations are largely unknown. We therefore used magnetoencephalography to record and directly compare first and second painrelated cortical responses to cutaneous laser stimuli in humans. Our results show that brief painful stimuli evoke sustained cortical activity corresponding to sustained pain perception comprising early first pain-related and late second pain-related components. Cortical activity was located in primary (S1) and secondary (S2) somatosensory cortices and anterior cingulate cortex. Time courses of activations disclosed that first pain was particularly related to activation of S1 whereas second pain was closely related to anterior cingulate cortex activation. Both sensations were associated with S2 activation. These results correspond to the different perceptual characteristics of both sensations and probably reflect different biological functions of first and second pain. First pain signals threat and provides precise sensory information for an immediate withdrawal, whereas second pain attracts longerlasting attention and motivates behavioral responses to limit further injury and optimize recovery. I t is a unique perceptual phenomenon that single painful stimuli yield two successive and qualitatively distinct sensations referred to as first and second pain sensation (1-4). First pain is brief, pricking, and well localized, whereas second pain is longer-lasting, burning, and less well localized. Peripherally, the neural basis of this phenomenon is a dual pathway for pain with A␦ and C fibers mediating first and second pain, respectively (2, 3). Different conduction velocities of both fiber types of about 10-20 and 1 m/s (5, 6) account for the temporal sequence of both sensations with reaction times to first pain of 400-500 ms and to second pain of about 1,000 ms after application of painful stimuli to the hand (1, 2, 4, 7).The biological functions and the differential cortical correlates of first and second pain are less well known. Anatomical, physiological, and lesion studies in humans and animals have revealed an extensive cortical network associated with sensory, cognitive, and affective aspects of pain (for review, see ref. 8). This network consistently includes primary (S1) and secondary (S2) somatosensory cortices, insular cortex, and anterior cingulate cortex (ACC). However, only a few studies disentangled A␦ and C fiber activations and, thus, first and second pain. Neurophysiological recordings in humans revealed early A␦ fibermediated activations in S1, S2, and ACC (for review, see ref. 8), whereas C fiber-mediated cortical responses at latencies of about 1,000 ms have been shown in scalp recordings (9-13) but have not yet been consistently localized. Conversely, ...

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Section: Discussionsupporting

confidence: 86%

mentioning

confidence: 99%

Cortical representation of first and second pain sensation in humans

Ploner

Groß

Timmermann

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

204

109

View full text Add to dashboard Cite

show abstract

“…Indeed, because the thermal activation threshold of C-fiber afferents is consistently lower than the thermal activation threshold of A␦-fiber afferents (difference, 2.3-3°C) (Plaghki et al, 2010), reducing the energy density of the laser stimulus constitutes one of the previously validated methods to activate C-nociceptors selectively (for review, see Plaghki andMouraux, 2002, 2005;Plaghki, 2007), and this approach has been already used successfully in several previous studies (Treede et al, 1995;Towell et al, 1996;Magerl et al, 1999;Agostino et al, 2000;Tran et al, 2002;Cruccu et al, 2003;Iannetti et al, 2003;Mouraux et al, 2003;Qiu et al, 2006;Mouraux and Plaghki, 2007).…”

Section: Steady-state Thermal Stimulation Of A␦-and C-nociceptorsmentioning

confidence: 99%

Nociceptive Steady-State Evoked Potentials Elicited by Rapid Periodic Thermal Stimulation of Cutaneous Nociceptors

Mouraux¹,

Iannetti²,

Colon³

et al. 2011

J. Neurosci.

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The periodic presentation of a sensory stimulus induces, at certain frequencies of stimulation, a sustained electroencephalographic response known as steady-state evoked potential (SS-EP). In the somatosensory, visual, and auditory modalities, SS-EPs are considered to constitute an electrophysiological correlate of cortical sensory networks resonating at the frequency of stimulation. In the present study, we describe and characterize, for the first time, SS-EPs elicited by the selective activation of skin nociceptors in humans. The stimulation consisted of 2.3-s-long trains of 16 identical infrared laser pulses (frequency, 7 Hz), applied to the dorsum of the left and right hand and foot. Two different stimulation energies were used. The low energy activated only C-nociceptors, whereas the high energy activated both A␦-and C-nociceptors. Innocuous electrical stimulation of large-diameter A␤-fibers involved in the perception of touch and vibration was used as control. The high-energy nociceptive stimulus elicited a consistent SS-EP, related to the activation of A␦-nociceptors. Regardless of stimulus location, the scalp topography of this response was maximal at the vertex. This was noticeably different from the scalp topography of the SS-EPs elicited by innocuous vibrotactile stimulation, which displayed a clear maximum over the parietal region contralateral to the stimulated side. Therefore, we hypothesize that the SS-EPs elicited by the rapid periodic thermal activation of nociceptors may reflect the activation of a network that is preferentially involved in processing nociceptive input and may thus provide some important insight into the cortical processes generating painful percepts.

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“…Although waveforms consistent with an ultralate (C-mediated) LEP have been recorded in the immediate wake of a late (Aδ-mediated) LEP, (Magerl et al, 1999) a fiber-specific origin of the suspected ultralate response could not be established; nor could an incomplete suppressive effect of the preceding Aδ response be ruled out. Indeed, Towell and colleagues (Towell et al, 1996) noticed that the ultra-late LEPs could be recorded most frequently when the stimulus intensity was low and the late LEPs less well identified. These observations support our finding that the mutually suppressive interaction depends on the magnitude of the conditioning stimulus.…”

Section: The Interaction Of Aδ and C Signals Is Intensity Dependentmentioning

confidence: 99%

An inhibitory interaction of human cortical responses to stimuli preferentially exciting Aδ or C fibers

2008

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Finely myelinated (type Aδ) and unmyelinated (type C) fibers are the major afferent inputs to spinothalamic tract neurons mediating sensory and reflex responses to noxious and thermal stimuli. These two fiber types differ in their sensory and biophysical properties, raising questions about the interaction of their supraspinal responses. Therefore, we investigated the interaction of cortical responses to stimuli that preferentially excite these fibers in human subjects using evoked potential recordings in a paired conditioning stimulation (CS) and test stimulation (TS) paradigm. There were two experiments, one with Aδ as CS and C as TS (Aδ-C) and another with these stimuli reversed (C-Aδ). We used intra-epidermal electrical pulses applied to the dorsal left hand at 2 and 1 × pinprick threshold (pp) for the preferential stimulation of Aδ fibers and 37 -50°C contact heat pulses applied to the left or right thenar and left hypothenar eminences for the preferential stimulation of C fibers. We found that the cortical response to preferential Aδ or C fiber stimulation was attenuated whenever either cortical response preceded the other. Standardized values of peak and integrated amplitudes were < 1 in all paring conditions and in all subjects in both experiments. The suppressive effect varied in magnitude with the intensity of the conditioning stimulus in both Aδ-C and C-Aδ experiments. Furthermore, intra-segmental interaction was differentially effective for Aδ conditioning, (peak amplitude, p < 0.008; ANOVA). Our experiments provide the first neurophysiological evidence for a somatotopically distributed, mutually suppressive interaction between cortical responses to preferentially activated Aδ and C afferents in humans. This suppressive interaction of cortical responses suggests contrasting and possibly mutually exclusive sensori-motor functions mediated through the Aδ and C fiber afferent channels. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptNeuroscience. Author manuscript; available in PMC 2008 June 20. Published in final edited form as:Neuroscience. 2008 March 27; 152(3): 798-808. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptAs a population, spinothalamic neurons receive direct synaptic input from a variety of somatic and visceral afferent fibers. The cutaneous afferent inputs include large diameter myelinated (Aβ) fibers that are activated only by tactile stimuli and small diameter, finely myelinated (Aδ) and unmyelinated (C) fibers innervating receptors responding to innocuous and noxious mechanical...

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CO2 laser activation of nociceptive and non-nociceptive thermal afferents from hairy and glabrous skin

Cited by 81 publications

References 19 publications

Cortical representation of first and second pain sensation in humans

Cortical representation of first and second pain sensation in humans

Nociceptive Steady-State Evoked Potentials Elicited by Rapid Periodic Thermal Stimulation of Cutaneous Nociceptors

An inhibitory interaction of human cortical responses to stimuli preferentially exciting Aδ or C fibers

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