Stability of Sensory Topographies in Adult Cortex

Makin, Tamar R.; Bensmaı̈a, Sliman J.

doi:10.1016/j.tics.2017.01.002

Cited by 114 publications

(105 citation statements)

References 69 publications

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“…Error bars = SEM. FST, foot size task; HST, hand size task; *significant difference (p < .05) between pre-and post-rTMS assessment limb seems to remain stable despite the loss of the peripheral input (Kikkert et al, 2016;Makin & Bensmaia, 2017;Makin, Scholz, Henderson Slater, Johansen-Berg, & Tracey, 2015).…”

Section: Discussionmentioning

confidence: 99%

Somatosensory cortical representation of the body size

Giurgola

Pisoni

Maravita

et al. 2019

Human Brain Mapping

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The knowledge of the size of our own body parts is essential for accurately moving in space and efficiently interact with objects. A distorted perceptual representation of the body size often represents a core diagnostic criterion for some psychopathological conditions. The metric representation of the body was shown to depend on somatosensory afferences: local deafferentation indeed causes a perceptual distortion of the size of the anesthetized body part. A specular effect can be induced by altering the cortical map of body parts in the primary somatosensory cortex. Indeed, the present study demonstrates, in healthy adult participants, that repetitive Transcranial Magnetic Stimulation to the somatosensory cortical map of the hand in both hemispheres causes a perceptual distortion (i.e., an overestimation) of the size of the participants' own hand (Experiments 1–3), which does not involve other body parts (i.e., the foot, Experiment 2). Instead, the stimulation of the inferior parietal lobule of both hemispheres does not affect the perception of the own body size (Experiment 4). These results highlight the role of the primary somatosensory cortex in the building up and updating of the metric of body parts: somatosensory cortical activity not only shapes our somatosensation, it also affects how we perceive the dimension of our body.

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Section: Discussionmentioning

confidence: 99%

Somatosensory cortical representation of the body size

Giurgola

Pisoni

Maravita

et al. 2019

Human Brain Mapping

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“…Hence, loss of input from a body region in adulthood may lead to the formation or potentiation of lateral connections in the brainstem, which gives rise to a new pathway from periphery to cortex. It is not clear whether this new pathway contributes to cortical reorganisation, but the original pathway seems to be relatively spared even under the extreme circumstance of limb amputation (Makin and Bensmaia, 2017).…”

Section: Discussionmentioning

confidence: 99%

Fine-grained mapping of cortical somatotopies in chronic Complex Regional Pain Syndrome

Mancini

Wang

Schira

et al. 2018

Preprint

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32It has long been thought that severe chronic pain conditions, such as Complex Regional 33 Pain Syndrome (CRPS), are not only associated with, but even maintained by a 34 reorganisation of the somatotopic representation of the affected limb in primary 35 somatosensory cortex (S1). This notion has driven treatments that aim to restore S1 36 representations, such as sensory discrimination training and mirror therapy. However, 37 this notion is based on both indirect and incomplete evidence obtained with imaging 38 methods with low spatial resolution. Here, we used functional MRI to characterize the S1 39 representation of the affected and unaffected hand in patients with unilateral CRPS. At 40 the group level, the cortical area, location, and geometry of the S1 representation of the 41 CRPS hand were largely comparable to those of the healthy hand and controls. 42However, the area of the map of the affected hand was modulated by disease duration 43 (the smaller the map, the more chronic the CRPS), but not by pain intensity, pain 44 sensitivity and severity of the physical disability. Thus, if any map reorganization occurs, 45it does not appear to be directly related to our pain measures. These findings compel us 46 to reconsider the cortical mechanisms underlying CRPS and the rationale for 47 interventions that aim to "restore" somatotopic representations to treat pain. 49Significance statement 50 51This study shows that the spatial map of the fingers in S1 is largely preserved in chronic 52 CRPS. Shrinkage of the area of the affected hand map can occur in the most chronic 53 stages of disease. Map shrinkage is related to CRPS duration rather than diagnosis, and 54 is unrelated to how much pain patients experience or to the severity of the physical 55 disability. These findings challenge the rationale for using sensory interventions to treat 56 pain by restoring somatotopic representations in CRPS patients. 58 59 Introduction 60Chronic pain is a highly common and debilitating disorder, that can be associated with 61 functional and morphological changes in the brain. For instance, it has long been 62 thought that some severe chronic pain conditions, such as Complex Regional Pain 63 Syndrome (CRPS), are not only associated with, but even maintained by, maladaptive 64 topographic changes in the primary somatosensory cortex (S1) (Maihofner et al., 2003, 93 quantification of the representation of the fingers (i.e. with exclusion of the thumb) in 94 patients with chronic and unilateral CRPS to the upper limb. We tested whether the S1 95 representation of the fingertips of the affected hand was different from that of the healthy 96 hand of CRPS patients and from controls in terms of its spatial extent, location relative to 97 the central sulcus, and geometry (i.e. variability of the map gradients). 98 99 Materials and Methods 100 101 4 Participants. We recruited 20 adults with unilateral CRPS to the upper limb and 20 102 healthy controls (HC) matched for age, gender and handedness. Each participant gave 103 written inf...

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“…An integrative explanatory hypothesis for the mechanisms responsible for generating phantom pain suggests the potential of coexistence between reorganizational processes of the cortex with the expansion of cortical map neighboring the deafferented area and the abnormal spontaneous activity of the area now deprived of peripheral input 84. The maladaptive plasticity and persistent representation models may be not mutually exclusive 85,86…”

Section: Discussionmentioning

confidence: 99%

Capsaicin 8% patch treatment for amputation stump and phantom limb pain: a clinical and functional MRI study

Privitera¹,

Birch²,

Sinisi³

et al. 2017

JPR

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PurposeThe aim of this study was to measure the efficacy of a single 60 min application of capsaicin 8% patch in reducing chronic amputation stump and phantom limb pain, associated hypersensitivity with quantitative sensory testing, and changes in brain cortical maps using functional MRI (fMRI) scans.MethodsA capsaicin 8% patch (Qutenza) treatment study was conducted on 14 patients with single limb amputation, who reported pain intensity on the Numerical Pain Rating Scale ≥4/10 for chronic stump or phantom limb pain. Pain assessments, quantitative sensory testing, and fMRI (for the lip pursing task) were performed at baseline and 4 weeks after application of capsaicin 8% patch to the amputation stump. The shift into the hand representation area of the cerebral cortex with the lip pursing task has been correlated with phantom limb pain intensity in previous studies, and was the fMRI clinical model for cortical plasticity used in this study.ResultsThe mean reduction in spontaneous amputation stump pain, phantom limb pain, and evoked stump pain were −1.007 (p=0.028), −1.414 (p=0.018), and −2.029 (p=0.007), respectively. The areas of brush allodynia and pinprick hypersensitivity in the amputation stump showed marked decreases: −165 cm2, −80% (p=0.001) and −132 cm2, −72% (p=0.001), respectively. fMRI analyses provided objective evidence of the restoration of the brain map, that is, reversal of the shift into the hand representation of the cerebral cortex with the lip pursing task (p<0.05).ConclusionThe results show that capsaicin 8% patch treatment leads to significant reduction in chronic pain and, particularly, in the area of stump hypersensitivity, which may enable patients to wear prostheses, thereby improving mobility and rehabilitation. Phantom limb pain (“central” pain) and associated brain plasticity may be modulated by peripheral inputs, as they can be ameliorated by the peripherally restricted effect of the capsaicin 8% patch.

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Stability of Sensory Topographies in Adult Cortex

Cited by 114 publications

References 69 publications

Somatosensory cortical representation of the body size

Somatosensory cortical representation of the body size

Fine-grained mapping of cortical somatotopies in chronic Complex Regional Pain Syndrome

Capsaicin 8% patch treatment for amputation stump and phantom limb pain: a clinical and functional MRI study

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