Temporo-spatial analysis of cortical activation by phasic innocuous and noxious cold stimuli – a magnetoencephalographic study

Maihöfner, Christian; Kaltenhäuser, Martin; Neundörfer, B.; Lang, E.

doi:10.1016/s0304-3959(02)00276-2

Cited by 87 publications

(74 citation statements)

References 46 publications

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“…A laser-evoked potential study provided evidence that selective warming specifically activates the dpIns (29), and recent fMRI studies provided supplemental data supporting activation of the insular cortex by cooling and "paradoxical heat" (3,18,20). Notably, imaging evidence also indicates strong activation of the human dpIns by noxious cold (8,12,36).…”

Section: Discussionmentioning

confidence: 96%

Anteroposterior somatotopy of innocuous cooling activation focus in human dorsal posterior insular cortex

Hua¹,

Strigo²,

Baxter³

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

113

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Prior data indicate that graded activation by innocuous thermal stimuli occurs in the dorsal posterior insular (dpIns) cortex of humans, rather than the parietal somatosensory regions traditionally thought necessary for discriminative somatic sensations. We hypothesized that if the dpIns subserves the haptic capacity of localization in addition to discrimination, then it should be somatotopically organized. Using functional magnetic resonance imaging to detect activation in the dpIns by graded cooling stimuli applied to the hand and neck, we found unimodal foci arranged in an anteroposterior somatotopographic pattern, consistent with participation of the dpIns in localization as well as discrimination. This gradient is orthogonal to the mediolateral somatotopy of parietal somatosensory regions, which supports the fundamental conceptual differentiation of the interoceptive somatic representation in the dpIns from the parietal exteroceptive representations. These data also support the suggestion that the poststroke central pain syndrome associated with lesions of the dpIns is a thermoregulatory dysfunction. Finally, another focus of strongly graded activation, which we interpret to represent thermoregulatory behavioral motivation elicited by dynamic cooling, was observed in the dorsal medial cortex.temperature; homeostasis; interoception; thermoregulation; functional imaging THERMAL SENSATIONS IN HUMANS (i.e., sensations of cool, warm, cold, and hot) are important for tactile recognition of objects and for homeostatic control of body temperature, functions that are traditionally differentiated as exteroceptive and interoceptive, respectively (28). The exteroceptive aspect of (innocuous and noxious) thermal sensibility has been regarded as a capacity of the somatosensory system, allied with the sense of touch. Specifically, it has been thought that the haptic abilities to discriminate different temperatures and to localize thermal stimuli on the body must involve the somatotopically wellorganized system that represents discriminative cutaneous mechanoreception (23,43). This has been an explicit presumption at least since Weber's analysis of somatic sensation in 1846 (47).However, recent findings indicate that the cortical substrate for discriminative innocuous thermal sensation is not part of the somatosensory cortices but, rather, is located in the insula, which is associated with autonomic control (14). This site is the terminus of a spinothalamocortical pathway, phylogenetically distinct to primates and highly developed in humans, that is an expansion of a homeostatic afferent system representing the physiological condition of the body (16). These new findings fundamentally revise our understanding of the neural representation of feelings from the body (16).To verify and extend these findings, we used functional magnetic resonance imaging (fMRI) to examine thermosensory activation sites in the dorsal posterior insula (dpIns). Our central hypothesis is that if the thermosensory representation in the dpIns partici...

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Section: Discussionmentioning

confidence: 96%

Anteroposterior somatotopy of innocuous cooling activation focus in human dorsal posterior insular cortex

Hua¹,

Strigo²,

Baxter³

et al. 2005

American Journal of Physiology-Regulatory, Integrative and Comp

113

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“…Three in whom the parietal operculum and posterior insula were involved had raised heat pain, innocuous cool, and mechanical pain thresholds in the contralateral hand. Maihöfner et al [26]have recently published a magnetoencephalographic study of cortical activity following innocuous and noxious cold stimulation of the hand dorsum. Innocuous cold stimulation evoked activity only in the posterior insular cortex bilaterally – with a shorter latency for the side ipsilateral to the stimulus.…”

Section: Discussionmentioning

confidence: 99%

Central Representation of Somatic Sensations in the Parietal Operculum (SII) and Insula

2004

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Four subjects with small restricted cerebral cortical infarcts have been examined. One had a lesion confined to the parietal operculum (SII), while in the second the SII lesion also encroached on the posterior insula; in the third subject, both banks of the sylvian fissure and the dorsal insula were involved, while in the fourth the lesion involved the upper bank of the sylvian fissure. In all cases, the postcentral gyrus (SI) was intact. Subjects 1 and 2 had mild spontaneous pain, but subjects 3 and 4 had never had spontaneous pain. In the affected areas, none could feel mechanical (skinfold pinch) pain. The 2 subjects with spontaneous pain could not discriminate sharpness (pinprick), but this was unimpaired in the third and fourth subjects. Warmth, cold, and heat pain were impaired in the 2 subjects with spontaneous pain, but not in those without; however warm-cold difference was greater in the affected regions of all subjects. The possibility must nevertheless be considered that the presence of central pain in some way alters the cortical mechanisms for the perception of thermal stimuli. Certainly, as we had earlier observed, spontaneous pain only occurs when there is interference with thermal sensation. Functional MRI (fMRI) studies following thermal stimulation in subjects 1 and 2 showed these areas, particularly SII, to be concerned with the reception of innocuous and noxious thermal stimuli, mechanical (skinfold pinch) pain and sharpness (pinprick), implying that SI is principally concerned with the reception of low-intensity mechanical stimuli, although it was activated in 1 of our fMRI-studied subjects by innocuous cooling.

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“…This device has already been used by us and others in previous psychophysical and functional imaging studies to explore tactile-induced sensations and central somatosensory processing [6,17,19,20,23]. The skin contact area was a circular rubber bladder, 10 mm in diameter, and the intensity of mechanical stimulation was 40 g/cm 2 .The rise time was 20 ms as measured from 10 to 90 % of the intensity increment.…”

Section: ■ Experimental Design and Tactile Stimulationmentioning

confidence: 99%

Mislocalization of tactile stimulation in patients with complex regional pain syndrome

et al. 2006

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Complex-Regional-Pain-Syndromes (CRPS) are characterized by sensory,motor and autonomic dysfunctions. Patterns of sensory symptoms suggest changes within the central nervous system (CNS). Recently, we could show substantial reorganization of somatotopic maps within the central nervous system of patients with CRPS using functional imaging techniques (Maihofner et al. Neurology, 2003). These changes were predicted by CRPS pain and mechanical hyperalgesia. In the present study we looked for potential psychophysical correlates of cortical reorganization in CRPS. Sequential pneumatic non-noxious tactile stimulation was performed at digits 1 and 5 in 24 patients with CRPS of the upper extremities. Both the unaffected and affected side were examined. Patients were interviewed for tactile induced sensations. The occurrence of mislocalizations was correlated with a detailed psychophysical examination in which sensory, motor and autonomic symptoms were assessed. Eight patients (30 %) reported tactile mislocalizations, which were felt in the affected hand. In four cases the referred sensations spread into other nerve territories (ulnar/median nerve). Presence of mechanical hyperalgesia significantly predicted the occurrence of mislocalizations. In contrast, in a healthy control group, no mislocalizations were found. Thus, our results further support the concept of pain-induced reorganization in the somatosensory system of CRPS patients.

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Temporo-spatial analysis of cortical activation by phasic innocuous and noxious cold stimuli – a magnetoencephalographic study

Cited by 87 publications

References 46 publications

Anteroposterior somatotopy of innocuous cooling activation focus in human dorsal posterior insular cortex

Anteroposterior somatotopy of innocuous cooling activation focus in human dorsal posterior insular cortex

Central Representation of Somatic Sensations in the Parietal Operculum (SII) and Insula

Mislocalization of tactile stimulation in patients with complex regional pain syndrome

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