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Shen Y, Wang W, Wang Y, Yang L, Yuan C, Yang Y, Wu F, Wang J, Deng Y, Wang X, Liu H. Not Only in Sensorimotor Network: Local and Distant Cerebral Inherent Activity of Chronic Ankle Instability—A Resting-State fMRI Study. Front Neurosci 2022; 16:835538. [PMID: 35197822 PMCID: PMC8859266 DOI: 10.3389/fnins.2022.835538] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/10/2022] [Indexed: 12/26/2022] Open
Abstract
BackgroundIncreasing evidence has proved that chronic ankle instability (CAI) is highly related to the central nervous system (CNS). However, it is still unclear about the inherent cerebral activity among the CAI patients.PurposeTo investigate the differences of intrinsic functional cerebral activity between the CAI patients and healthy controls (HCs) and further explore its correlation with clinical measurement in CAI patients.Materials and MethodsA total of 25 CAI patients and 39 HCs were enrolled in this study. Resting-state functional magnetic resonance imaging (rs-fMRI) was used to detect spontaneous cerebral activity. The metrics of amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), and regional homogeneity (ReHo) of the two groups were compared by two-sample t-test. The brain regions that demonstrated altered functional metrics were selected as the regions of interest (ROIs). The functional connectivity (FC) was analyzed based on the ROIs. The Spearman correlation was calculated between rs-fMRI metrics and clinical scale scores.ResultsCompared with HCs, CAI patients showed higher ALFF and ReHo values in the right postcentral gyrus, the right precentral gyrus, and the right middle frontal gyrus, while lower fALFF values in the orbital-frontal cortex (OFC, p < 0.01 after correction). Increasing FC between the right precentral gyrus and the right postcentral gyrus while decreasing FC between the right precentral gyrus and the anterior cingulum cortex (ACC), the right middle frontal gyrus and the left middle temporal gyrus, and the OFC and left inferior parietal lobule (IPL) was observed. In addition, in the CAI group, the ReHo value negatively correlated with the Cumberland Ankle Instability Tool score in the right middle frontal gyrus (r = −0.52, p = 0.007).ConclusionThe CAI patients exhibited enhanced and more coherent regional inherent neuronal activity within the sensorimotor network while lower regional inherent activity in pain/emotion modulation related region. In addition, the information exchanges were stronger within the sensorimotor network while weaker between distant interhemispheric regions. Besides, the increased inherent activity in the right middle frontal gyrus was related to clinical severity. These findings may provide insights into the pathophysiological alteration in CNS among CAI patients.
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Affiliation(s)
- Yiyuan Shen
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Weiwei Wang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yin Wang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
- Department of Radiology, Eye & ENT Hospital, Fudan University, Shanghai, China
| | - Liqin Yang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
- Institute of Functional and Molecular Medical Imaging, Fudan University, Shanghai, China
| | - Chengjie Yuan
- Department of Orthopedic, Huashan Hospital, Fudan University, Shanghai, China
| | - Yang Yang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Fei Wu
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
- Department of Radiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Junlong Wang
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yan Deng
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Xu Wang
- Department of Orthopedic, Huashan Hospital, Fudan University, Shanghai, China
- Xu Wang,
| | - Hanqiu Liu
- Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China
- *Correspondence: Hanqiu Liu,
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Testing the exteroceptive function of nociception: The role of visual experience in shaping the spatial representations of nociceptive inputs. Cortex 2020; 126:26-38. [PMID: 32062141 DOI: 10.1016/j.cortex.2019.12.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/21/2019] [Accepted: 12/14/2019] [Indexed: 01/30/2023]
Abstract
Adequately localizing pain is crucial to protect the body against physical damage and react to the stimulus in external space having caused such damage. Accordingly, it is hypothesized that nociceptive inputs are remapped from a somatotopic reference frame, representing the skin surface, towards a spatiotopic frame, representing the body parts in external space. This ability is thought to be developed and shaped by early visual experience. To test this hypothesis, normally sighted and early blind participants performed temporal order judgment tasks during which they judged which of two nociceptive stimuli applied on each hand's dorsum was perceived as first delivered. Crucially, tasks were performed with the hands either in an uncrossed posture or crossed over body midline. While early blinds were not affected by the posture, performances of the normally sighted participants decreased in the crossed condition relative to the uncrossed condition. This indicates that nociceptive stimuli were automatically remapped into a spatiotopic representation that interfered with somatotopy in normally sighted individuals, whereas early blinds seemed to mostly rely on a somatotopic representation to localize nociceptive inputs. Accordingly, the plasticity of the nociceptive system would not purely depend on bodily experiences but also on crossmodal interactions between nociception and vision during early sensory experience.
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Augmented Pain Processing in Primary and Secondary Somatosensory Cortex in Fibromyalgia: A Magnetoencephalography Study Using Intra-Epidermal Electrical Stimulation. PLoS One 2016; 11:e0151776. [PMID: 26992095 PMCID: PMC4798786 DOI: 10.1371/journal.pone.0151776] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 03/03/2016] [Indexed: 11/19/2022] Open
Abstract
The aim of this study was to investigate augmented pain processing in the cortical somatosensory system in patients with fibromyalgia (FM). Cortical evoked responses were recorded in FM (n = 19) and healthy subjects (n = 21) using magnetoencephalography after noxious intra-epidermal electrical stimulation (IES) of the hand dorsum (pain rating 6 on a numeric rating scale, perceptually-equivalent). In addition, healthy subjects were stimulated using the amplitude corresponding to the average stimulus intensity rated 6 in patients with FM (intensity-equivalent). Quantitative sensory testing was performed on the hand dorsum or thenar muscle (neutral site) and over the trapezius muscle (tender point), using IES (thresholds, ratings, temporal summation of pain, stimulus-response curve) and mechanical stimuli (threshold, ratings). Increased amplitude of cortical responses was found in patients with FM as compared to healthy subjects. These included the contralateral primary (S1) and bilateral secondary somatosensory cortices (S2) in response to intensity-equivalent stimuli and the contralateral S1 and S2 in response to perceptually-equivalent stimuli. The amplitude of the contralateral S2 response in patients with FM was positively correlated with average pain intensity over the last week. Quantitative sensory testing results showed that patients with FM were more sensitive to painful IES as well as to mechanical stimulation, regardless of whether the stimulation site was the hand or the trapezius muscle. Interestingly, the slope of the stimulus-response relationship as well as temporal summation of pain in response to IES was not different between groups. Together, these results suggest that the observed pain augmentation in response to IES in patients with FM could be due to sensitization or disinhibition of the cortical somatosensory system. Since the S2 has been shown to play a role in higher-order functions, further studies are needed to clarify the role of augmented S2 response in clinical characteristics of FM.
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Mochizuki H, Kakigi R. Itch and brain. J Dermatol 2015; 42:761-7. [DOI: 10.1111/1346-8138.12956] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 04/16/2015] [Indexed: 01/23/2023]
Affiliation(s)
- Hideki Mochizuki
- Department of Dermatology; Temple University School of Medicine; Temple Itch Center; Philadelphia Pennsylvania USA
| | - Ryusuke Kakigi
- Department of Integrative Physiology; National Institute for Physiological Sciences; Okazaki Japan
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Nakata H, Sakamoto K, Honda Y, Kakigi R. Temporal dynamics of neural activity in motor execution and inhibition processing. Eur J Neurosci 2015; 41:1448-58. [DOI: 10.1111/ejn.12889] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 03/04/2015] [Accepted: 03/06/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Hiroki Nakata
- Department of Integrative Physiology; National Institute for Physiological Sciences; Okazaki Japan
- Department of Health Sciences; Faculty of Human Life and Environment; Nara Women's University; Kitauoya-Nishi Machi Nara City 630-8506 Japan
| | - Kiwako Sakamoto
- Department of Integrative Physiology; National Institute for Physiological Sciences; Okazaki Japan
| | - Yukiko Honda
- Department of Integrative Physiology; National Institute for Physiological Sciences; Okazaki Japan
| | - Ryusuke Kakigi
- Department of Integrative Physiology; National Institute for Physiological Sciences; Okazaki Japan
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Mochizuki H, Kakigi R. Central mechanisms of itch. Clin Neurophysiol 2014; 126:1650-60. [PMID: 25534483 DOI: 10.1016/j.clinph.2014.11.019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 10/31/2014] [Accepted: 11/18/2014] [Indexed: 10/24/2022]
Abstract
Itch is a complex sensory and emotional experience. Functional brain imaging studies have been performed to identify brain regions associated with this complex experience, and these studies reported that several brain regions are activated by itch stimuli. The possible roles of these regions in itch perception and difference in cerebral mechanism between healthy subjects and chronic itch patients are discussed in this review article. Additionally, the central itch modulation system and cerebral mechanisms of contagious itch, pleasurable sensation evoked by scratching have also been investigated in previous brain imaging studies. We also discuss how these studies advance our understanding of these mechanisms.
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Affiliation(s)
- Hideki Mochizuki
- Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan; Department of Dermatology and Temple Itch Center, Temple University School of Medicine, Philadelphia, PA, USA.
| | - Ryusuke Kakigi
- Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Aichi, Japan
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Otsuru N, Hashizume A, Nakamura D, Endo Y, Inui K, Kakigi R, Yuge L. Sensory incongruence leading to hand disownership modulates somatosensory cortical processing. Cortex 2014; 58:1-8. [DOI: 10.1016/j.cortex.2014.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/24/2014] [Accepted: 05/12/2014] [Indexed: 11/17/2022]
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Yamashiro K, Sato D, Onishi H, Sugawara K, Nakazawa S, Kameyama S, Maruyama A. Effect of changes in stimulus site on activation of the posterior parietal cortex. Brain Topogr 2014; 28:261-8. [PMID: 24878895 DOI: 10.1007/s10548-014-0378-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 05/10/2014] [Indexed: 11/24/2022]
Abstract
A previous functional magnetic resonance imaging study elucidated the specific activity of the inferior parietal lobe (IPL) during a two-point discrimination task compared with that during an intensity discrimination task Akatsuka et al. (Neuroimage 40: 852-858, 2008). If the posterior parietal cortex (PPC), including IPL, is responsible for detecting changes in stimulus sites, PPC activity depends on the level of change at stimulus sites. The aim of this study was to clarify whether a particular site exists that could detect changes in stimulus sites using the oddball paradigm. Somatosensory-evoked magnetic fields were recorded in 10 right-handed subjects. Three oddball conditions were performed by all subjects, with the probability of deviant and standard stimuli being 20 and 80 %, respectively, under all three conditions. Deviant stimuli were always presented to the second digit of the hand and standard stimuli were presented to the first (small deviance: SD) and fifth digits (medium deviance: MD) of the hand and the first digit of the toe (large deviance: LD). Inter-stimulus intervals were set at 500 ms. A brain electrical source analysis showed that activities of areas 1 and 3b elicited by the deviant stimuli were not significantly different among the three conditions. In contrast, PPC activity was significantly greater for LD than for SD and MD. PPC activity tended to increase with greater deviance at stimulus sites, but activities of areas 1 and 3b did not differ. These findings suggest that PPC may have a functional role in automatic change detection systems with regard to deviance of stimulus sites.
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Affiliation(s)
- Koya Yamashiro
- Institute for Human Movement and Medical Sciences, Niigata University of Health and Welfare, Niigata, 950-3198, Japan,
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Favril L, Mouraux A, Sambo CF, Legrain V. Shifting attention between the space of the body and external space: Electrophysiological correlates of visual-nociceptive crossmodal spatial attention. Psychophysiology 2014; 51:464-77. [DOI: 10.1111/psyp.12157] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 07/18/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Louis Favril
- Department of Experimental Clinical and Health Psychology; Ghent University; Ghent Belgium
| | - André Mouraux
- Institute of Neuroscience; Université catholique de Louvain; Brussels Belgium
| | - Chiara F. Sambo
- Department of Neuroscience; Physiology and Pharmacology; University College London; London UK
| | - Valéry Legrain
- Department of Experimental Clinical and Health Psychology; Ghent University; Ghent Belgium
- Institute of Neuroscience; Université catholique de Louvain; Brussels Belgium
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Mouraux A, De Paepe AL, Marot E, Plaghki L, Iannetti GD, Legrain V. Unmasking the obligatory components of nociceptive event-related brain potentials. J Neurophysiol 2013; 110:2312-24. [DOI: 10.1152/jn.00137.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
It has been hypothesized that the human cortical responses to nociceptive and nonnociceptive somatosensory inputs differ. Supporting this view, somatosensory-evoked potentials (SEPs) elicited by thermal nociceptive stimuli have been suggested to originate from areas 1 and 2 of the contralateral primary somatosensory (S1), operculo-insular, and cingulate cortices, whereas the early components of nonnociceptive SEPs mainly originate from area 3b of S1. However, to avoid producing a burn lesion, and sensitize or fatigue nociceptors, thermonociceptive SEPs are typically obtained by delivering a small number of stimuli with a large and variable interstimulus interval (ISI). In contrast, the early components of nonnociceptive SEPs are usually obtained by applying many stimuli at a rapid rate. Hence, previously reported differences between nociceptive and nonnociceptive SEPs could be due to differences in signal-to-noise ratio and/or differences in the contribution of cognitive processes related, for example, to arousal and attention. Here, using intraepidermal electrical stimulation to selectively activate Aδ-nociceptors at a fast and constant 1-s ISI, we found that the nociceptive SEPs obtained with a long ISI are no longer identified, indicating that these responses are not obligatory for nociception. Furthermore, using a blind source separation, we found that, unlike the obligatory components of nonnociceptive SEPs, the obligatory components of nociceptive SEPs do not receive a significant contribution from a contralateral source possibly originating from S1. Instead, they were best explained by sources compatible with bilateral operculo-insular and/or cingulate locations. Taken together, our results indicate that the obligatory components of nociceptive and nonnociceptive SEPs are fundamentally different.
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Affiliation(s)
- A. Mouraux
- Institute of Neuroscience (IoNS), Université catholique de Louvain, Brussels, Belgium
| | - A. L. De Paepe
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium; and
| | - E. Marot
- Institute of Neuroscience (IoNS), Université catholique de Louvain, Brussels, Belgium
| | - L. Plaghki
- Institute of Neuroscience (IoNS), Université catholique de Louvain, Brussels, Belgium
| | - G. D. Iannetti
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, United Kingdom
| | - V. Legrain
- Institute of Neuroscience (IoNS), Université catholique de Louvain, Brussels, Belgium
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium; and
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Omori S, Isose S, Otsuru N, Nishihara M, Kuwabara S, Inui K, Kakigi R. Somatotopic representation of pain in the primary somatosensory cortex (S1) in humans. Clin Neurophysiol 2013; 124:1422-30. [DOI: 10.1016/j.clinph.2013.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 01/11/2013] [Accepted: 01/12/2013] [Indexed: 10/27/2022]
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12
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Canavero S, Bonicalzi V. Role of primary somatosensory cortex in the coding of pain. Pain 2013; 154:1156-1158. [PMID: 23590938 DOI: 10.1016/j.pain.2013.02.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
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Emotional facial expressions modulate pain-induced beta and gamma oscillations in sensorimotor cortex. J Neurosci 2011; 31:14542-50. [PMID: 21994371 DOI: 10.1523/jneurosci.6002-10.2011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Painful events in our environment are often accompanied by stimuli from other sensory modalities. These stimuli may influence the perception and processing of acute pain, in particular when they comprise emotional cues, like facial expressions of people surrounding us. In this whole-head magnetoencephalography (MEG) study, we examined the neuronal mechanisms underlying the influence of emotional (fearful, angry, or happy) compared to neutral facial expressions on the processing of pain in humans. Independent of their valence, subjective pain ratings for intracutaneous inputs were higher when pain stimuli were presented together with emotional facial expressions than when they were presented with a neutral facial expression. Source reconstruction using linear beamforming revealed pain-induced early (70-270 ms) oscillatory beta-band activity (BBA; 15-25 Hz) and gamma-band activity (GBA; 60-80 Hz) in the sensorimotor cortex. The presentation of faces with emotional expressions compared to faces with neutral expressions led to a stronger bilateral suppression of the pain-induced BBA, possibly reflecting enhanced response readiness of the sensorimotor system. Moreover, pain-induced GBA in the sensorimotor cortex was larger for faces expressing fear than for faces expressing anger, which might reflect the facilitation of avoidance-motivated behavior triggered by the concurrent presentation of faces with fearful expressions and painful stimuli. Thus, the presence of emotional cues, like facial expressions from people surrounding us, while receiving acute pain may facilitate neuronal processes involved in the preparation and execution of adequate protective motor responses.
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15
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Onishi H, Oyama M, Soma T, Kubo M, Kirimoto H, Murakami H, Kameyama S. Neuromagnetic activation of primary and secondary somatosensory cortex following tactile-on and tactile-off stimulation. Clin Neurophysiol 2010; 121:588-93. [DOI: 10.1016/j.clinph.2009.12.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2009] [Revised: 11/24/2009] [Accepted: 12/17/2009] [Indexed: 10/19/2022]
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Keeping pain in mind: A motivational account of attention to pain. Neurosci Biobehav Rev 2010; 34:204-13. [DOI: 10.1016/j.neubiorev.2009.01.005] [Citation(s) in RCA: 267] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 01/08/2009] [Accepted: 01/19/2009] [Indexed: 11/19/2022]
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Caetano G, Olausson H, Cole J, Jousmäki V, Hari R. Cortical responses to Aδ-fiber stimulation: magnetoencephalographic recordings in a subject lacking large myelinated afferents. Cereb Cortex 2009; 20:1898-903. [PMID: 19959562 PMCID: PMC2901021 DOI: 10.1093/cercor/bhp260] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Controversy persists over the role of the primary somatosensory cortex (SI) in processing small-fiber peripheral afferent input. We therefore examined subject I.W, who, due to sensory neuronopathy syndrome, has no large-fiber afferents below C3 level. Cortical evoked responses were recorded with a whole-scalp neuromagnetometer to high-intensity electrical stimulation of the distal right radial, median, and tibial nerves and skin over the forearm and mechanical stimulation of (neurologically intact) lip. The responses to electrical stimulation in the Aβ-denervated limbs peaked at 110–140 ms in contralateral SI and at 140–220 ms in contralateral secondary somatosensory cortex (SII), consistent with Aδ-mediated input. I.W. was able to localize pin-prick stimuli with 4 cm accuracy. Responses to laser stimuli on the radial dorsum of the hand peaked in contralateral SII cortex at 215 ms, also compatible with Aδ-mediated input. These results support the role of the SI cortex in processing the sensory discriminative aspects of Aδ-mediated input.
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Affiliation(s)
- Gina Caetano
- Brain Research Unit, Low Temperature Laboratory, Helsinki University of Technology, FIN-02015 Espoo, Finland
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Mochizuki H, Inui K, Tanabe HC, Akiyama LF, Otsuru N, Yamashiro K, Sasaki A, Nakata H, Sadato N, Kakigi R. Time Course of Activity in Itch-Related Brain Regions: A Combined MEG–fMRI Study. J Neurophysiol 2009; 102:2657-66. [DOI: 10.1152/jn.00460.2009] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Functional neuroimaging studies have identified itch-related brain regions. However, no study has investigated the temporal aspect of itch-related brain processing. Here this issue was investigated using electrically evoked itch in ten healthy adults. Itch stimuli were applied to the left wrist and brain activity was measured using magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI). In the MEG experiment, the magnetic responses evoked by the itch stimuli were observed in the contralateral and ipsilateral frontotemporal regions. The dipoles associated with the magnetic responses were mainly located in the contralateral (nine subjects) and ipsilateral (eight subjects) secondary somatosensory cortex (SII)/insula, which were also activated by the itch stimuli in the fMRI experiment. We also observed an itch-related magnetic response in the posterior part of the centroparietal region in six subjects. MEG and fMRI data showed that the magnetic response in this region was mainly associated with itch-related activation of the precuneus. The latency was significantly longer in the ipsilateral than that in the contralateral SII/insula, suggesting the difference to be associated with transmission in the callosal fibers. The timing of activation of the precuneus was between those of the contralateral and ipsilateral SII/insula. Other sources were located in the premotor, primary motor, and anterior cingulate cortices (one subject each). This study is the first to demonstrate part of the time course of itch-related brain processing. Combining methods with high temporal and spatial resolution (e.g., MEG and fMRI) would be useful to investigate the temporal aspect of the brain mechanism of itch.
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Affiliation(s)
- Hideki Mochizuki
- Department of Integrative Physiology and
- Japanese Foundation for Neuroscience and Mental Health
| | - Koji Inui
- Department of Integrative Physiology and
- Department of Physiological Sciences, School of Life Sciences, Graduate University for Advanced Studies, Kanagawa, Japan; and
| | - Hiroki C. Tanabe
- Department of Cerebral Research, National Institute for Physiological Sciences
- Department of Physiological Sciences, School of Life Sciences, Graduate University for Advanced Studies, Kanagawa, Japan; and
| | - Lisa F. Akiyama
- Department of Biology and
- Department of Psychology, University of Washington, Seattle, Washington
| | - Naofumi Otsuru
- Department of Integrative Physiology and
- Department of Physiological Sciences, School of Life Sciences, Graduate University for Advanced Studies, Kanagawa, Japan; and
| | - Koya Yamashiro
- Department of Integrative Physiology and
- Department of Physiological Sciences, School of Life Sciences, Graduate University for Advanced Studies, Kanagawa, Japan; and
| | - Akihiro Sasaki
- Department of Cerebral Research, National Institute for Physiological Sciences
- Department of Physiological Sciences, School of Life Sciences, Graduate University for Advanced Studies, Kanagawa, Japan; and
| | - Hiroki Nakata
- Department of Integrative Physiology and
- School of Health Sciences, Nagoya University, Aichi
- Japan Society for the Promotion of Science, Tokyo
| | - Norihiro Sadato
- Department of Cerebral Research, National Institute for Physiological Sciences
- Department of Physiological Sciences, School of Life Sciences, Graduate University for Advanced Studies, Kanagawa, Japan; and
| | - Ryusuke Kakigi
- Department of Integrative Physiology and
- Department of Physiological Sciences, School of Life Sciences, Graduate University for Advanced Studies, Kanagawa, Japan; and
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