Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and Reinnervation
Despite state-of-the-art surgical and postoperative treatment, median nerve transection causes lasting impaired hand function due to limitations in the nerve’s reinnervation ability. The defective innervation and thus controllability of the affected hand can shape the brain’s control of manual behav...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2020-05-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fnhum.2020.00166/full |
| _version_ | 1818390629923684352 |
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| author | Per F. Nordmark Per F. Nordmark Per F. Nordmark Roland S. Johansson Roland S. Johansson |
| author_facet | Per F. Nordmark Per F. Nordmark Per F. Nordmark Roland S. Johansson Roland S. Johansson |
| author_sort | Per F. Nordmark |
| collection | DOAJ |
| description | Despite state-of-the-art surgical and postoperative treatment, median nerve transection causes lasting impaired hand function due to limitations in the nerve’s reinnervation ability. The defective innervation and thus controllability of the affected hand can shape the brain’s control of manual behaviors. Earlier studies of changes in the processing of tactile stimuli have focused mainly on stimulation of the reinnervated hand and lack sufficient control over the brain’s use of the tactile input in perceptual terms. Here we used fMRI to measure brain activity (BOLD-signal) in 11 people with median nerve injury and healthy controls (N = 11) when performing demanding tactile tasks using the tip of either the index or little finger of either hand. For the nerve-injured group, the left median nerve had been traumatically transected in the distal forearm and surgically repaired on average 8 years before the study. The hand representation of their contralesional (right) primary somatosensory cortex (S1) showed greater activity compared to controls when the left reinnervated index finger was used, but also when the left-hand little finger and the fingers of the right hand innervated by uninjured nerves were used. We argue that the overall increase in activity reflects a general disinhibition of contralesional S1 consistent with an augmented functional reorganizational plasticity being an ongoing feature of chronic recovery from nerve injury. Also, the nerve-injured showed increased activity within three prefrontal cortical areas implicated in higher-level behavioral processing (dorsal anterior cingulate cortex, left ventrolateral prefrontal and right dorsolateral prefrontal cortex), suggesting that processes supporting decision-making and response-selection were computationally more demanding due to the compromised tactile sensibility. |
| first_indexed | 2024-12-14T05:00:40Z |
| format | Article |
| id | doaj.art-082cbad5f92941b89079984de4fd3b52 |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-12-14T05:00:40Z |
| publishDate | 2020-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-082cbad5f92941b89079984de4fd3b522022-12-21T23:16:14ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612020-05-011410.3389/fnhum.2020.00166519404Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and ReinnervationPer F. Nordmark0Per F. Nordmark1Per F. Nordmark2Roland S. Johansson3Roland S. Johansson4Department of Integrative Medical Biology, Physiology Section, Umeå University, Umeå, SwedenUmeå Center for Functional Brain Imaging, Umeå University, Umeå, SwedenDepartment of Surgical and Perioperative Sciences, Section for Hand and Plastic Surgery, Umeå University, Umeå, SwedenDepartment of Integrative Medical Biology, Physiology Section, Umeå University, Umeå, SwedenUmeå Center for Functional Brain Imaging, Umeå University, Umeå, SwedenDespite state-of-the-art surgical and postoperative treatment, median nerve transection causes lasting impaired hand function due to limitations in the nerve’s reinnervation ability. The defective innervation and thus controllability of the affected hand can shape the brain’s control of manual behaviors. Earlier studies of changes in the processing of tactile stimuli have focused mainly on stimulation of the reinnervated hand and lack sufficient control over the brain’s use of the tactile input in perceptual terms. Here we used fMRI to measure brain activity (BOLD-signal) in 11 people with median nerve injury and healthy controls (N = 11) when performing demanding tactile tasks using the tip of either the index or little finger of either hand. For the nerve-injured group, the left median nerve had been traumatically transected in the distal forearm and surgically repaired on average 8 years before the study. The hand representation of their contralesional (right) primary somatosensory cortex (S1) showed greater activity compared to controls when the left reinnervated index finger was used, but also when the left-hand little finger and the fingers of the right hand innervated by uninjured nerves were used. We argue that the overall increase in activity reflects a general disinhibition of contralesional S1 consistent with an augmented functional reorganizational plasticity being an ongoing feature of chronic recovery from nerve injury. Also, the nerve-injured showed increased activity within three prefrontal cortical areas implicated in higher-level behavioral processing (dorsal anterior cingulate cortex, left ventrolateral prefrontal and right dorsolateral prefrontal cortex), suggesting that processes supporting decision-making and response-selection were computationally more demanding due to the compromised tactile sensibility.https://www.frontiersin.org/article/10.3389/fnhum.2020.00166/fullhumanshandperipheral nerve injurytouchmagnetic resonance imagingsomatosensory cortex |
| spellingShingle | Per F. Nordmark Per F. Nordmark Per F. Nordmark Roland S. Johansson Roland S. Johansson Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and Reinnervation Frontiers in Human Neuroscience humans hand peripheral nerve injury touch magnetic resonance imaging somatosensory cortex |
| title | Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and Reinnervation |
| title_full | Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and Reinnervation |
| title_fullStr | Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and Reinnervation |
| title_full_unstemmed | Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and Reinnervation |
| title_short | Disinhibition of Human Primary Somatosensory Cortex After Median Nerve Transection and Reinnervation |
| title_sort | disinhibition of human primary somatosensory cortex after median nerve transection and reinnervation |
| topic | humans hand peripheral nerve injury touch magnetic resonance imaging somatosensory cortex |
| url | https://www.frontiersin.org/article/10.3389/fnhum.2020.00166/full |
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