Inter-hemispheric plasticity in patients with median nerve injury

Fornander, Lotta; Nyman, Torbjörn; Hansson, Thomas; Brismar, Tom; Engström, Maria

doi:10.1016/j.neulet.2016.06.018

Cited by 9 publications

(6 citation statements)

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“…Ipsilateral finger representations are engaged in active movement, but not during somatosensory processing (Berlot et al, 2018). Peripheral nerve injury can enhance activity in ipsilateral S1 (Fornander et al, 2016), especially at the level of interneurons in laminae V and VI (Pelled et al, 2009). Crucially, ipsilateral activations and deactivations in S1 are diffused and not somatotopically specific (Helmich et al, 2005; Reed et al, 2011; Ann Stringer et al, 2014; Geva et al, 2017).…”

Section: Methodsmentioning

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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Section: Methodsmentioning

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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“…37,38 Recruiting bilateral neural resources may be compensation for the faulty sensorimotor circuit. [39][40][41] Enhanced FCs after nerve transfer were only observed in the contralateral hemispherical, including right motor cortex and right piriform cortex, suggesting the contralateral motor representation regained control of the affected limb. Peripheral pathway alteration disrupts integrity of the sensorimotor network, which is critical for maintaining synergy and correcting sensory and motor performance.…”

Section: Discussionmentioning

confidence: 99%

Altered Neural Pathways and Related Brain Remodeling: A Rat Study Using Different Nerve Reconstructions

et al. 2023

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BACKGROUND: Function recovery is related to cortical plasticity. The brain remodeling patterns induced by alterations in peripheral nerve pathways with different nerve reconstructions are unknown. OBJECTIVE: To explore brain remodeling patterns related to alterations in peripheral neural pathways after different nerve reconstruction surgeries. METHODS: Twenty-four female Sprague-Dawley rats underwent complete left brachial plexus nerve transection, together with the following interventions: no nerve repair (n = 8), grafted nerve repair (n = 8), and phrenic nerve transfer (n = 8). Resting-state functional MR images of brain were acquired at the end of seventh month postsurgery. Amplitude of low-frequency fluctuation (ALFF), regional homogeneity (ReHo), and functional connectivity (FC) were compared among 3 groups. Behavioral observation and electromyography assessed nerve regeneration. RESULTS: Compared with brachial plexus injury group, ALFF and ReHo of left entorhinal cortex decreased in nerve repair and nerve transfer groups. The nerve transfer group showed increased ALFF and ReHo than nerve repair group in left caudate putamen, right accumbens nucleus shell (AcbSh), and right somatosensory cortex. The FC between right somatosensory cortex and bilateral piriform cortices and bilateral somatosensory cortices increased in nerve repair group than brachial plexus injury and nerve transfer groups. The nerve transfer group showed increased FC between right somatosensory cortex and areas including left corpus callosum, left retrosplenial cortex, right parietal association cortex, and right dorsolateral thalamus than nerve repair group. CONCLUSION: Entorhinal cortex is a key brain area in recovery of limb function after nerve reconstruction. Nerve transfer related brain remodeling mainly involved contralateral sensorimotor areas, facilitating directional “shifting” of motor representation.

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“…Improved muscle function was probably due to plastic processes at many levels. 19 – 22 , 32 Regarding the cortical level at least three findings indicate plastic changes. At the time of the AIN transfer, both patients were in a stable chronic phase after the nerve injury.…”

Section: Discussionmentioning

confidence: 99%

“…The human brain is capable of reorganization following injury, demonstrated for median and ulnar nerve lesions 19 , 20 and for nerve transfers at the spinal nerve root level in animals and humans. 21 , 22 To explore the neuro anatomy and physiological mechanisms of central plasticity, navigated transcranial magnetic stimulation (nTMS) may be used to probe the system with high resolution.…”

Section: Introductionmentioning

confidence: 99%

Neuroplasticity following Nerve Transfer of the Anterior Interosseous Nerve for Proximal Ulnar Nerve Injuries

Nyman

Rubensson

et al. 2021

Plastic and Reconstructive Surgery - Global Open

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Background: Injuries to the ulnar nerve at or above proximal forearm level result in poor recovery despite early microsurgical repair, especially concerning the intrinsic motor function of the hand. To augment the numbers of regenerating axons into the targeted muscles, a nerve transfer of the distal branch of the median nerve, the anterior interosseous nerve, to the ulnar motor branch has been described. Methods: Two patients with severe atrophy of the intrinsic hand muscles following an initial proximal ulnar nerve repair had surgery with an end-to-side transfer of the anterior interosseous nerve to the ulnar motor branch at the wrist level. Outcome and neuroplasticity were prospectively studied using questionnaires, clinical examinations, electroneurography, electromyography, somatosensory evoked potentials at pre nerve transfer and 3-, 12-, and 24-months post nerve transfer as well as navigated transcranial magnetic stimulation at pre nerve transfer and 3- and 12-months post nerve transfer. Results: Successively improved motor function was observed. Complete reinnervation of intrinsic hand muscles was demonstrated at 12- to 24-months follow-up by electroneurography and electromyography. At the cortical level, navigated transcranial magnetic stimulation detected a movement of the hot-spot for the abductor digiti mini muscle, originally innervated by the ulnar nerve and the size of the area from where responses could be elicited in this muscle changed over time, indicating central plastic processes. An almost complete reinnervation of the pronator quadratus muscle was also observed. Conclusion: Both central and peripheral plastic mechanisms are involved in muscle reinnervation after anterior interosseous nerve transfer for treatment of proximal ulnar nerve injuries.

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Inter-hemispheric plasticity in patients with median nerve injury

Cited by 9 publications

References 100 publications

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

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

Altered Neural Pathways and Related Brain Remodeling: A Rat Study Using Different Nerve Reconstructions

Neuroplasticity following Nerve Transfer of the Anterior Interosseous Nerve for Proximal Ulnar Nerve Injuries

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