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Wu C, Zhang H, Hong H, Chen C, Chen J, Zhang J, Xue P, Jiang J, Cui Z. E3 ubiquitin ligase Triad1 promotes neuronal apoptosis by regulating the p53-caspase3 pathway after spinal cord injury. Somatosens Mot Res 2021; 39:21-28. [PMID: 34641746 DOI: 10.1080/08990220.2021.1986385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE Spinal cord injury entails a high risk of major disability, but there is still no effective treatment for this condition. This study aims to explore the neuronal apoptosis after spinal cord injury, which is a key component of secondary injury processes, and plays a critical role in the development of neurological dysfunction. MATERIALS AND METHODS We studied the expression of the E3 ubiquitin ligase Triad1 and its interaction with p53 in the spinal cord after a spinal cord contusion injury in rats. We explored the regulation function of Triad1 to the neuronal apoptosis through p53-caspase3 pathway in primary neurons. RESULTS Triad1 was markedly up-regulated in the grey matter one day after injury, and the distribution and time point of Triad1 expression correlated with the presence of apoptotic neurons. Co-immunoprecipitation experiments further demonstrated that Triad1 interacted with p53 after spinal cord injury. Specific siRNA and overexpression plasmids for Triad1 were transfected into primary neurons, and the expression of both p53 and caspase3 was altered following the change of Triad1. CONCLUSIONS These findings indicate that Triad1 is involved in regulating the pathological process of neuronal apoptosis mediated by p53-caspase3 pathway after spinal cord injury.
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Affiliation(s)
- Chunshuai Wu
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
| | - Huiyu Zhang
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
| | - Hongxiang Hong
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
| | - Chu Chen
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
| | - Jiajia Chen
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
| | - Jinlong Zhang
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
| | - Pengfei Xue
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
| | - Jiawei Jiang
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
| | - Zhiming Cui
- Department of Spine Surgery, Affiliated Hospital 2 of Nantong University, Nantong University, The First People's Hospital of Nantong, Nantong, Jiangsu, People's Republic of China
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Chen G, Wu H, Chen N, Wang M, Shi L, Li J, Wei F, Xu Z, Liu X, Liu S. Potential of intraoperative ultrasonographic assessment of the spinal cord central echo complex in predicting postoperative neurological recovery of degenerative cervical myelopathy. Eur J Neurol 2021; 29:217-224. [PMID: 34528341 DOI: 10.1111/ene.15109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 09/09/2021] [Indexed: 01/24/2023]
Abstract
BACKGROUND AND PURPOSE The spinal cord central echo complex (SCCEC) is a special ultrasonography-based intramedullary structure, but its clinical significance in degenerative cervical myelopathy (DCM) is undefined. This study aimed to explore the potential of the SCCEC in predicting postoperative neurological recovery in DCM. METHODS Thirty-two DCM patients who underwent intraoperative ultrasonography-guided French-door laminoplasty were prospectively enrolled. The modified Japanese Orthopaedic Association (mJOA) score was evaluated preoperatively and 12 months postoperatively. SCCEC width (SCCEC-W), and anteroposterior diameter (APD) and transverse diameter (TD) of the spinal cord were measured on transverse ultrasonographic images, while the tissue widths from anterior and posterior borders of the spinal cord to the SCCEC were measured on sagittal ultrasonographic images. The APD of the spinal cord and occupying rate of the spinal canal were measured on preoperative magnetic resonance imaging (MRI). RESULTS All patients achieved improvements in mJOA scores, with an average recovery rate (RR) of 68.69 ± 20.22%. Spearman correlation analysis revealed that SCCEC-W, and ratios between the SCCEC-W and APD/TD based on ultrasonography, correlated moderately with mJOA score RR, with coefficients of -0.527, -0.605 and -0.514, respectively. The ratio between SCCEC-W and ultrasonographic TD correlated moderately with preoperative APD of the spinal cord. The MRI measurements and ultrasonography-based tissue widths showed no significant correlation with mJOA score RR. CONCLUSIONS The SCCEC may have predictive potential as an intraoperative indicator of neurological recovery in treating DCM. SCCEC-W may be related to spinal cord compression in DCM.
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Affiliation(s)
- Guoliang Chen
- Guangdong Provincial Biomedical Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopedic Surgery, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China.,Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology /Orthopaedic Research Institute, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Huachuan Wu
- Guangdong Provincial Biomedical Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopedic Surgery, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China.,Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology /Orthopaedic Research Institute, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ningning Chen
- Guangdong Provincial Biomedical Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopedic Surgery, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Meng Wang
- Department of Radiology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Liangyu Shi
- Guangdong Provincial Biomedical Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopedic Surgery, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Jiachun Li
- Guangdong Provincial Biomedical Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopedic Surgery, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Fuxin Wei
- Guangdong Provincial Biomedical Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopedic Surgery, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Zuofeng Xu
- Department of Ultrasound, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Xizhe Liu
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology /Orthopaedic Research Institute, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Shaoyu Liu
- Guangdong Provincial Biomedical Innovation Platform of Regeneration and Repair of Spinal Cord and Nerve Injury, Department of Orthopedic Surgery, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China.,Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology /Orthopaedic Research Institute, Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
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Qi HX, Reed JL, Wang F, Gross CL, Liu X, Chen LM, Kaas JH. Longitudinal fMRI measures of cortical reactivation and hand use with and without training after sensory loss in primates. Neuroimage 2021; 236:118026. [PMID: 33930537 PMCID: PMC8409436 DOI: 10.1016/j.neuroimage.2021.118026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 03/18/2021] [Accepted: 03/26/2021] [Indexed: 11/28/2022] Open
Abstract
In a series of previous studies, we demonstrated that damage to the dorsal column in the cervical spinal cord deactivates the contralateral somatosensory hand cortex and impairs hand use in a reach-to-grasp task in squirrel monkeys. Nevertheless, considerable cortical reactivation and behavioral recovery occurs over the following weeks to months after lesion. This timeframe may also be a window for targeted therapies to promote cortical reactivation and functional reorganization, aiding in the recovery process. Here we asked if and how task specific training of an impaired hand would improve behavioral recovery and cortical reorganization in predictable ways, and if recovery related cortical changes would be detectable using noninvasive functional magnetic resonance imaging (fMRI). We further asked if invasive neurophysiological mapping reflected fMRI results. A reach-to-grasp task was used to test impairment and recovery of hand use before and after dorsal column lesions (DC-lesion). The activation and organization of the affected primary somatosensory cortex (area 3b) was evaluated with two types of fMRI - either blood oxygenation level dependent (BOLD) or cerebral blood volume (CBV) with a contrast agent of monocrystalline iron oxide nanocolloid (MION) - before and after DC-lesion. At the end of the behavioral and fMRI studies, microelectrode recordings in the somatosensory areas 3a, 3b and 1 were used to characterize neuronal responses and verify the somatotopy of cortical reactivations. Our results indicate that even after nearly complete DC lesions, monkeys had both considerable post-lesion behavioral recovery, as well as cortical reactivation assessed with fMRI followed by extracellular recordings. Generalized linear regression analyses indicate that lesion extent is correlated with the behavioral outcome, as well as with the difference in the percent signal change from pre-lesion peak activation in fMRI. Monkeys showed behavioral recovery and nearly complete cortical reactivation by 9-12 weeks post-lesion (particularly when the DC-lesion was incomplete). Importantly, the specific training group revealed trends for earlier behavioral recovery and had higher magnitude of fMRI responses to digit stimulation by 5-8 weeks post-lesion. Specific kinematic measures of hand movements in the selected retrieval task predicted recovery time and related to lesion characteristics better than overall task performance success. For measures of cortical reactivation, we found that CBV scans provided stronger signals to vibrotactile digit stimulation as compared to BOLD scans, and thereby may be the preferred non-invasive way to study the cortical reactivation process after sensory deprivations from digits. When the reactivation of cortex for each of the digits was considered, the reactivation by digit 2 stimulation as measured with microelectrode maps and fMRI maps was best correlated with overall behavioral recovery.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA.
| | - Jamie L. Reed
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Feng Wang
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA,Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | | | - Xin Liu
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Li Min Chen
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA,Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Jon H. Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA,Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA
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Liao C, Qi H, Reed JL, Jeoung H, Kaas JH. Corticocuneate projections are altered after spinal cord dorsal column lesions in New World monkeys. J Comp Neurol 2021; 529:1669-1702. [PMID: 33029803 PMCID: PMC7987845 DOI: 10.1002/cne.25050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 12/31/2022]
Abstract
Recovery of responses to cutaneous stimuli in the area 3b hand cortex of monkeys after dorsal column lesions (DCLs) in the cervical spinal cord relies on neural rewiring in the cuneate nucleus (Cu) over time. To examine whether the corticocuneate projections are modified during recoveries after the DCL, we injected cholera toxin subunit B into the hand representation in Cu to label the cortical neurons after various recovery times, and related results to the recovery of neural responses in the affected area 3b hand cortex. In normal New World monkeys, labeled neurons were predominately distributed in the hand regions of contralateral areas 3b, 3a, 1 and 2, parietal ventral (PV), secondary somatosensory cortex (S2), and primary motor cortex (M1), with similar distributions in the ipsilateral cortex in significantly smaller numbers. In monkeys with short-term recoveries, the area 3b hand neurons were unresponsive or responded weakly to touch on the hand, while the cortical labeling pattern was largely unchanged. After longer recoveries, the area 3b hand neurons remained unresponsive, or responded to touch on the hand or somatotopically abnormal parts, depending on the lesion extent. The distributions of cortical labeled neurons were much more widespread than the normal pattern in both hemispheres, especially when lesions were incomplete. The proportion of labeled neurons in the contralateral area 3b hand cortex was not correlated with the functional reactivation in the area 3b hand cortex. Overall, our findings indicated that corticocuneate inputs increase during the functional recovery, but their functional role is uncertain.
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Affiliation(s)
- Chia‐Chi Liao
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Hui‐Xin Qi
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Jamie L. Reed
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Ha‐Seul Jeoung
- Department of Psychology Vanderbilt University Nashville Tennessee USA
| | - Jon H. Kaas
- Department of Psychology Vanderbilt University Nashville Tennessee USA
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Chen G, Wei F, Li J, Shi L, Zhang W, Wang X, Xu Z, Liu X, Zou X, Liu S. Intensity of Intraoperative Spinal Cord Hyperechogenicity as a Novel Potential Predictive Indicator of Neurological Recovery for Degenerative Cervical Myelopathy. Korean J Radiol 2021; 22:1163-1171. [PMID: 33739631 PMCID: PMC8236360 DOI: 10.3348/kjr.2020.0755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/29/2020] [Accepted: 11/03/2020] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE To analyze the correlations between intraoperative ultrasound and MRI metrics of the spinal cord in degenerative cervical myelopathy and identify novel potential predictive ultrasonic indicators of neurological recovery for degenerative cervical myelopathy. MATERIALS AND METHODS Twenty-two patients who underwent French-door laminoplasty for multilevel degenerative cervical myelopathy were followed up for 12 months. The Japanese Orthopedic Association (JOA) scores were assessed preoperatively and 12 months postoperatively. Maximum spinal cord compression and compression rates were measured and calculated using both intraoperative ultrasound imaging and preoperative T2-weight (T2W) MRI. Signal change rates of the spinal cord on preoperative T2W MRI and gray value ratios of dorsal and ventral spinal cord hyperechogenicity on intraoperative ultrasound imaging were measured and calculated. Correlations between intraoperative ultrasound metrics, MRI metrics, and the recovery rate JOA scores were analyzed using Spearman correlation analysis. RESULTS The postoperative JOA scores improved significantly, with a mean recovery rate of 65.0 ± 20.3% (p < 0.001). No significant correlations were found between the operative ultrasound metrics and MRI metrics. The gray value ratios of the spinal cord hyperechogenicity was negatively correlated with the recovery rate of JOA scores (ρ = -0.638, p = 0.001), while the ventral and dorsal gray value ratios of spinal cord hyperechogenicity were negatively correlated with the recovery rate of JOA-motor scores (ρ = -0.582, p = 0.004) and JOA-sensory scores (ρ = -0.452, p = 0.035), respectively. The dorsal gray value ratio was significantly higher than the ventral gray value ratio (p < 0.001), while the recovery rate of JOA-motor scores was better than that of JOA-sensory scores at 12 months post-surgery (p = 0.028). CONCLUSION For degenerative cervical myelopathy, the correlations between intraoperative ultrasound and preoperative T2W MRI metrics were not significant. Gray value ratios of the spinal cord hyperechogenicity and dorsal and ventral spinal cord hyperechogenicity were significantly correlated with neurological recovery at 12 months postoperatively.
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Affiliation(s)
- Guoliang Chen
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology/Orthopaedic Research Institute, Department of Spine Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Department of Orthopedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Fuxin Wei
- Department of Orthopedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Jiachun Li
- Department of Orthopedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Liangyu Shi
- Department of Orthopedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Wei Zhang
- Department of Orthopedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Xianxiang Wang
- Department of Ultrasound, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Zuofeng Xu
- Department of Ultrasound, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Xizhe Liu
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology/Orthopaedic Research Institute, Department of Spine Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
| | - Xuenong Zou
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology/Orthopaedic Research Institute, Department of Spine Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Shaoyu Liu
- Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology/Orthopaedic Research Institute, Department of Spine Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Department of Orthopedic Surgery, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
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6
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Qi HX, Liao CC, Reed JL, Kaas JH. Reorganization of Higher-Order Somatosensory Cortex After Sensory Loss from Hand in Squirrel Monkeys. Cereb Cortex 2020; 29:4347-4365. [PMID: 30590401 DOI: 10.1093/cercor/bhy317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/18/2018] [Accepted: 11/20/2018] [Indexed: 12/31/2022] Open
Abstract
Unilateral dorsal column lesions (DCL) at the cervical spinal cord deprive the hand regions of somatosensory cortex of tactile activation. However, considerable cortical reactivation occurs over weeks to months of recovery. While most studies focused on the reactivation of primary somatosensory area 3b, here, for the first time, we address how the higher-order somatosensory cortex reactivates in the same monkeys after DCL that vary across cases in completeness, post-lesion recovery times, and types of treatments. We recorded neural responses to tactile stimulation in areas 3a, 3b, 1, secondary somatosensory cortex (S2), parietal ventral (PV), and occasionally areas 2/5. Our analysis emphasized comparisons of the responsiveness, somatotopy, and receptive field size between areas 3b, 1, and S2/PV across DCL conditions and recovery times. The results indicate that the extents of the reactivation in higher-order somatosensory areas 1 and S2/PV closely reflect the reactivation in primary somatosensory cortex. Responses in higher-order areas S2 and PV can be stronger than those in area 3b, thus suggesting converging or alternative sources of inputs. The results also provide evidence that both primary and higher-order fields are effectively activated after long recovery times as well as after behavioral and electrocutaneous stimulation interventions.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
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7
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Vallotton K, Huber E, Sutter R, Curt A, Hupp M, Freund P. Width and neurophysiologic properties of tissue bridges predict recovery after cervical injury. Neurology 2019; 92:e2793-e2802. [PMID: 31092621 PMCID: PMC6598793 DOI: 10.1212/wnl.0000000000007642] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 02/07/2019] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE To assess whether preserved dorsal and ventral midsagittal tissue bridges after traumatic cervical spinal cord injury (SCI) encode tract-specific electrophysiologic properties and are predictive of appropriate recovery. METHODS In this longitudinal study, we retrospectively assessed MRI scans at 1 month after SCI that provided data on width and location (dorsal vs ventral) of midsagittal tissue bridges in 28 tetraplegic patients. Regression analysis assessed associations between midsagittal tissue bridges and motor- and sensory-specific electrophysiologic recordings and appropriate outcome measures at 12 months after SCI. RESULTS Greater width of dorsal midsagittal tissue bridges at 1 month after SCI identified patients who were classified as being sensory incomplete at 12 months after SCI (p = 0.025), had shorter sensory evoked potential (SEP) latencies (r = -0.57, p = 0.016), and had greater SEP amplitudes (r = 0.61, p = 0.001). Greater width of dorsal tissue bridges predicted better light-touch score at 12 months (r = 0.40, p = 0.045) independently of baseline clinical score and ventral tissue bridges. Greater width of ventral midsagittal tissue bridges at 1 month identified patients who were classified as being motor incomplete at 12 months (p = 0.002), revealed shorter motor evoked potential (MEP) latencies (r = -0.54, p = 0.044), and had greater ratios of MEP amplitude to compound muscle action potential amplitude (r = 0.56, p = 0.005). Greater width of ventral tissue bridges predicted better lower extremity motor scores at 12 months (r = 0.41, p = 0.035) independently of baseline clinical score and dorsal tissue bridges. CONCLUSION Midsagittal tissue bridges, detectable early after SCI, underwrite tract-specific electrophysiologic communication and are predictors of appropriate sensorimotor recovery. Neuroimaging biomarkers of midsagittal tissue bridges may be integrated into the diagnostic workup, prediction of recovery, and patients' stratification in clinical trials.
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Affiliation(s)
- Kevin Vallotton
- From the Spinal Cord Injury Center (K.V., E.H., A.C., M.H., P.F.) and Department of Radiology (R.S.), Balgrist University Hospital; University of Zurich (K.V., E.H., A.C., M.H., P.F., R.S.), Switzerland; Wellcome Trust Centre for Neuroimaging (P.F.) and Department of Brain Repair and Rehabilitation (P.F.), UCL Institute of Neurology, University College London, UK; and Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Eveline Huber
- From the Spinal Cord Injury Center (K.V., E.H., A.C., M.H., P.F.) and Department of Radiology (R.S.), Balgrist University Hospital; University of Zurich (K.V., E.H., A.C., M.H., P.F., R.S.), Switzerland; Wellcome Trust Centre for Neuroimaging (P.F.) and Department of Brain Repair and Rehabilitation (P.F.), UCL Institute of Neurology, University College London, UK; and Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Reto Sutter
- From the Spinal Cord Injury Center (K.V., E.H., A.C., M.H., P.F.) and Department of Radiology (R.S.), Balgrist University Hospital; University of Zurich (K.V., E.H., A.C., M.H., P.F., R.S.), Switzerland; Wellcome Trust Centre for Neuroimaging (P.F.) and Department of Brain Repair and Rehabilitation (P.F.), UCL Institute of Neurology, University College London, UK; and Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Armin Curt
- From the Spinal Cord Injury Center (K.V., E.H., A.C., M.H., P.F.) and Department of Radiology (R.S.), Balgrist University Hospital; University of Zurich (K.V., E.H., A.C., M.H., P.F., R.S.), Switzerland; Wellcome Trust Centre for Neuroimaging (P.F.) and Department of Brain Repair and Rehabilitation (P.F.), UCL Institute of Neurology, University College London, UK; and Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Markus Hupp
- From the Spinal Cord Injury Center (K.V., E.H., A.C., M.H., P.F.) and Department of Radiology (R.S.), Balgrist University Hospital; University of Zurich (K.V., E.H., A.C., M.H., P.F., R.S.), Switzerland; Wellcome Trust Centre for Neuroimaging (P.F.) and Department of Brain Repair and Rehabilitation (P.F.), UCL Institute of Neurology, University College London, UK; and Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Patrick Freund
- From the Spinal Cord Injury Center (K.V., E.H., A.C., M.H., P.F.) and Department of Radiology (R.S.), Balgrist University Hospital; University of Zurich (K.V., E.H., A.C., M.H., P.F., R.S.), Switzerland; Wellcome Trust Centre for Neuroimaging (P.F.) and Department of Brain Repair and Rehabilitation (P.F.), UCL Institute of Neurology, University College London, UK; and Department of Neurophysics (P.F.), Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
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Barroso FO, Yoder B, Tentler D, Wallner JJ, Kinkhabwala AA, Jantz MK, Flint RD, Tostado PM, Pei E, Satish ADR, Brodnick SK, Suminski AJ, Williams JC, Miller LE, Tresch MC. Decoding neural activity to predict rat locomotion using intracortical and epidural arrays. J Neural Eng 2019; 16:036005. [DOI: 10.1088/1741-2552/ab0698] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Filipp ME, Travis BJ, Henry SS, Idzikowski EC, Magnuson SA, Loh MY, Hellenbrand DJ, Hanna AS. Differences in neuroplasticity after spinal cord injury in varying animal models and humans. Neural Regen Res 2019; 14:7-19. [PMID: 30531063 PMCID: PMC6263009 DOI: 10.4103/1673-5374.243694] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Rats have been the primary model to study the process and underlying mechanisms of recovery after spinal cord injury. Two weeks after a severe spinal cord contusion, rats can regain weight-bearing abilities without therapeutic interventions, as assessed by the Basso, Beattie and Bresnahan locomotor scale. However, many human patients suffer from permanent loss of motor function following spinal cord injury. While rats are the most understood animal model, major differences in sensorimotor pathways between quadrupeds and bipeds need to be considered. Understanding the major differences between the sensorimotor pathways of rats, non-human primates, and humans is a start to improving targets for treatments of human spinal cord injury. This review will discuss the neuroplasticity of the brain and spinal cord after spinal cord injury in rats, non-human primates, and humans. A brief overview of emerging interventions to induce plasticity in humans with spinal cord injury will also be discussed.
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Affiliation(s)
- Mallory E Filipp
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Benjamin J Travis
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Stefanie S Henry
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Emma C Idzikowski
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Sarah A Magnuson
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | - Megan Yf Loh
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
| | | | - Amgad S Hanna
- Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA
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10
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Brain-controlled modulation of spinal circuits improves recovery from spinal cord injury. Nat Commun 2018; 9:3015. [PMID: 30068906 PMCID: PMC6070513 DOI: 10.1038/s41467-018-05282-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 06/22/2018] [Indexed: 01/07/2023] Open
Abstract
The delivery of brain-controlled neuromodulation therapies during motor rehabilitation may augment recovery from neurological disorders. To test this hypothesis, we conceived a brain-controlled neuromodulation therapy that combines the technical and practical features necessary to be deployed daily during gait rehabilitation. Rats received a severe spinal cord contusion that led to leg paralysis. We engineered a proportional brain-spine interface whereby cortical ensemble activity constantly determines the amplitude of spinal cord stimulation protocols promoting leg flexion during swing. After minimal calibration time and without prior training, this neural bypass enables paralyzed rats to walk overground and adjust foot clearance in order to climb a staircase. Compared to continuous spinal cord stimulation, brain-controlled stimulation accelerates and enhances the long-term recovery of locomotion. These results demonstrate the relevance of brain-controlled neuromodulation therapies to augment recovery from motor disorders, establishing important proofs-of-concept that warrant clinical studies.
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O'Shea DJ, Kalanithi P, Ferenczi EA, Hsueh B, Chandrasekaran C, Goo W, Diester I, Ramakrishnan C, Kaufman MT, Ryu SI, Yeom KW, Deisseroth K, Shenoy KV. Development of an optogenetic toolkit for neural circuit dissection in squirrel monkeys. Sci Rep 2018; 8:6775. [PMID: 29712920 PMCID: PMC5928036 DOI: 10.1038/s41598-018-24362-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 04/03/2018] [Indexed: 01/01/2023] Open
Abstract
Optogenetic tools have opened a rich experimental landscape for understanding neural function and disease. Here, we present the first validation of eight optogenetic constructs driven by recombinant adeno-associated virus (AAV) vectors and a WGA-Cre based dual injection strategy for projection targeting in a widely-used New World primate model, the common squirrel monkey Saimiri sciureus. We observed opsin expression around the local injection site and in axonal projections to downstream regions, as well as transduction to thalamic neurons, resembling expression patterns observed in macaques. Optical stimulation drove strong, reliable excitatory responses in local neural populations for two depolarizing opsins in anesthetized monkeys. Finally, we observed continued, healthy opsin expression for at least one year. These data suggest that optogenetic tools can be readily applied in squirrel monkeys, an important first step in enabling precise, targeted manipulation of neural circuits in these highly trainable, cognitively sophisticated animals. In conjunction with similar approaches in macaques and marmosets, optogenetic manipulation of neural circuits in squirrel monkeys will provide functional, comparative insights into neural circuits which subserve dextrous motor control as well as other adaptive behaviors across the primate lineage. Additionally, development of these tools in squirrel monkeys, a well-established model system for several human neurological diseases, can aid in identifying novel treatment strategies.
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Affiliation(s)
- Daniel J O'Shea
- Neurosciences Program, Stanford University, Stanford, CA, USA.
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA.
| | - Paul Kalanithi
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | | | - Brian Hsueh
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | | | - Werapong Goo
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Ilka Diester
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Otophysiologie, Albert Ludwig University of Freiburg, Freiburg im Breisgau, Germany
- BrainLinks-BrainTools, Albert Ludwig University of Freiburg, Freiburg im Breisgau, Germany
| | | | - Matthew T Kaufman
- Neurosciences Program, Stanford University, Stanford, CA, USA
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Stephen I Ryu
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
- Palo Alto Medical Foundation, Palo Alto, CA, USA
| | - Kristen W Yeom
- Department of Radiology, Stanford University, Stanford, CA, USA
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Psychiatry and Behavioral Science, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Krishna V Shenoy
- Neurosciences Program, Stanford University, Stanford, CA, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Neurobiology, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
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12
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Second-order spinal cord pathway contributes to cortical responses after long recoveries from dorsal column injury in squirrel monkeys. Proc Natl Acad Sci U S A 2018; 115:4258-4263. [PMID: 29610299 DOI: 10.1073/pnas.1718826115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Months after the occurrence of spinal cord dorsal column lesions (DCLs) at the cervical level, neural responses in the hand representation of somatosensory area 3b hand cortex recover, along with hand use. To examine whether the second-order spinal cord pathway contributes to this functional recovery, we injected cholera toxin subunit B (CTB) into the hand representation in the cuneate nucleus (Cu) to label the spinal cord neurons, and related results to cortical reactivation in four squirrel monkeys (Saimiri boliviensis) at least 7 months after DCL. In two monkeys with complete DCLs, few CTB-labeled neurons were present below the lesion, and few neurons in the affected hand region in area 3b responded to touch on the hand. In two other cases with large but incomplete DCLs, CTB-labeled neurons were abundant below the lesion, and the area 3b hand cortex responded well to tactile stimulation in a roughly somatotopic organization. The proportions of labeled neurons in the spinal cord hand region reflected the extent of cortical reactivation to the hand. Comparing monkeys with short and long recovery times suggests that the numbers of labeled neurons below the lesion increase with time following incomplete DCLs (<95%) but decrease with time after nearly complete DCLs (≥95%). Taken together, these results suggest that the second-order spinal cord pathway facilitates cortical reactivation, likely through the potentiation of persisting tactile inputs from the hand to the Cu over months of postlesion recovery.
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13
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Reed JL, Liao CC, Qi HX, Kaas JH. Plasticity and Recovery After Dorsal Column Spinal Cord Injury in Nonhuman Primates. J Exp Neurosci 2016; 10:11-21. [PMID: 27578996 PMCID: PMC4991577 DOI: 10.4137/jen.s40197] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 06/26/2016] [Accepted: 06/28/2016] [Indexed: 12/15/2022] Open
Abstract
Here, we review recent work on plasticity and recovery after dorsal column spinal cord injury in nonhuman primates. Plasticity in the adult central nervous system has been established and studied for the past several decades; however, capacities and limits of plasticity are still under investigation. Studies of plasticity include assessing multiple measures before and after injury in animal models. Such studies are particularly important for improving recovery after injury in patients. In summarizing work by our research team and others, we suggest how the findings from plasticity studies in nonhuman primate models may affect therapeutic interventions for conditions involving sensory loss due to spinal cord injury.
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Affiliation(s)
- Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
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14
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Qi HX, Wang F, Liao CC, Friedman RM, Tang C, Kaas JH, Avison MJ. Spatiotemporal trajectories of reactivation of somatosensory cortex by direct and secondary pathways after dorsal column lesions in squirrel monkeys. Neuroimage 2016; 142:431-453. [PMID: 27523450 DOI: 10.1016/j.neuroimage.2016.08.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/23/2016] [Accepted: 08/09/2016] [Indexed: 11/17/2022] Open
Abstract
After lesions of the somatosensory dorsal column (DC) pathway, the cortical hand representation can become unresponsive to tactile stimuli, but considerable responsiveness returns over weeks of post-lesion recovery. The reactivation suggests that preserved subthreshold sensory inputs become potentiated and axon sprouting occurs over time to mediate recovery. Here, we studied the recovery process in 3 squirrel monkeys, using high-resolution cerebral blood volume-based functional magnetic resonance imaging (CBV-fMRI) mapping of contralateral somatosensory cortex responsiveness to stimulation of distal finger pads with low and high level electrocutaneous stimulation (ES) before and 2, 4, and 6weeks after a mid-cervical level contralateral DC lesion. Both low and high intensity ES of digits revealed the expected somatotopy of the area 3b hand representation in pre-lesion monkeys, while in areas 1 and 3a, high intensity stimulation was more effective in activating somatotopic patterns. Six weeks post-lesion, and irrespective of the severity of loss of direct DC inputs (98%, 79%, 40%), somatosensory cortical area 3b of all three animals showed near complete recovery in terms of somatotopy and responsiveness to low and high intensity ES. However there was significant variability in the patterns and amplitudes of reactivation of individual digit territories within and between animals, reflecting differences in the degree of permanent and/or transient silencing of primary DC and secondary inputs 2weeks post-lesion, and their spatio-temporal trajectories of recovery between 2 and 6weeks. Similar variations in the silencing and recovery of somatotopy and responsiveness to high intensity ES in areas 3a and 1 are consistent with individual differences in damage to and recovery of DC and spinocuneate pathways, and possibly the potentiation of spinothalamic pathways. Thus, cortical deactivation and subsequent reactivation depends not only on the degree of DC lesion, but also on the severity and duration of loss of secondary as well as primary inputs revealed by low and high intensity ES.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA.
| | - Feng Wang
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Robert M Friedman
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Chaohui Tang
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA
| | - Malcolm J Avison
- Institute of Imaging Science, Vanderbilt University, Nashville, TN 37240, USA; Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37240, USA; Pharmacology, Vanderbilt University, Nashville, TN 37240, USA
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15
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Qi HX, Reed JL, Franca JG, Jain N, Kajikawa Y, Kaas JH. Chronic recordings reveal tactile stimuli can suppress spontaneous activity of neurons in somatosensory cortex of awake and anesthetized primates. J Neurophysiol 2016; 115:2105-23. [PMID: 26912593 DOI: 10.1152/jn.00634.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 02/19/2016] [Indexed: 01/05/2023] Open
Abstract
In somatosensory cortex, tactile stimulation within the neuronal receptive field (RF) typically evokes a transient excitatory response with or without postexcitatory inhibition. Here, we describe neuronal responses in which stimulation on the hand is followed by suppression of the ongoing discharge. With the use of 16-channel microelectrode arrays implanted in the hand representation of primary somatosensory cortex of New World monkeys and prosimian galagos, we recorded neuronal responses from single units and neuron clusters. In 66% of our sample, neuron activity tended to display suppression of firing when regions of skin outside of the excitatory RF were stimulated. In a small proportion of neurons, single-site indentations suppressed firing without initial increases in response to any of the tested sites on the hand. Latencies of suppressive responses to skin indentation (usually 12-34 ms) were similar to excitatory response latencies. The duration of inhibition varied across neurons. Although most observations were from anesthetized animals, we also found similar neuron response properties in one awake galago. Notably, suppression of ongoing neuronal activity did not require conditioning stimuli or multi-site stimulation. The suppressive effects were generally seen following single-site skin indentations outside of the neuron's minimal RF and typically on different digits and palm pads, which have not often been studied in this context. Overall, the characteristics of widespread suppressive or inhibitory response properties with and without initial facilitative or excitatory responses add to the growing evidence that neurons in primary somatosensory cortex provide essential processing for integrating sensory stimulation from across the hand.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
| | - Joao G Franca
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Neeraj Jain
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
| | - Yoshinao Kajikawa
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee; and
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16
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Liao CC, Qi HX, Reed JL, Miller DJ, Kaas JH. Congenital foot deformation alters the topographic organization in the primate somatosensory system. Brain Struct Funct 2016; 221:383-406. [PMID: 25326245 PMCID: PMC4446245 DOI: 10.1007/s00429-014-0913-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/07/2014] [Indexed: 12/20/2022]
Abstract
Limbs may fail to grow properly during fetal development, but the extent to which such growth alters the nervous system has not been extensively explored. Here we describe the organization of the somatosensory system in a 6-year-old monkey (Macaca radiata) born with a deformed left foot in comparison to the results from a normal monkey (Macaca fascicularis). Toes 1, 3, and 5 were missing, but the proximal parts of toes 2 and 4 were present. We used anatomical tracers to characterize the patterns of peripheral input to the spinal cord and brainstem, as well as between thalamus and cortex. We also determined the somatotopic organization of primary somatosensory area 3b of both hemispheres using multiunit electrophysiological recording. Tracers were subcutaneously injected into matching locations of each foot to reveal their representations within the lumbar spinal cord, and the gracile nucleus (GrN) of the brainstem. Tracers injected into the representations of the toes and plantar pads of cortical area 3b labeled neurons in the ventroposterior lateral nucleus (VPL) of the thalamus. Contrary to the orderly arrangement of the foot representation throughout the lemniscal pathway in the normal monkey, the plantar representation of the deformed foot was significantly expanded and intruded into the expected representations of toes in the spinal cord, GrN, VPL, and area 3b. We also observed abnormal representation of the intact foot in the ipsilateral spinal cord and contralateral area 3b. Thus, congenital malformation influences the somatotopic representation of the deformed as well as the intact foot.
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Affiliation(s)
- Chia-Chi Liao
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA.
| | - Hui-Xin Qi
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA
| | - Jamie L Reed
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA
| | - Daniel J Miller
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA
| | - Jon H Kaas
- 301 Wilson Hall, Department of Psychology, Vanderbilt University, 111 21st Avenue South, Nashville, TN, 37212, USA
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17
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Liao CC, Reed JL, Kaas JH, Qi HX. Intracortical connections are altered after long-standing deprivation of dorsal column inputs in the hand region of area 3b in squirrel monkeys. J Comp Neurol 2015; 524:1494-526. [PMID: 26519356 DOI: 10.1002/cne.23921] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 10/01/2015] [Accepted: 10/26/2015] [Indexed: 11/09/2022]
Abstract
A complete unilateral lesion of the dorsal column somatosensory pathway in the upper cervical spinal cord deactivates neurons in the hand region in contralateral somatosensory cortex (areas 3b and 1). Over weeks to months of recovery, parts of the hand region become reactivated by touch on the hand or face. To determine whether changes in cortical connections potentially contribute to this reactivation, we injected tracers into electrophysiologically identified locations in cortex of area 3b representing the reactivated hand and normally activated face in adult squirrel monkeys. Our results indicated that even when only partially reactivated, most of the expected connections of area 3b remained intact. These intact connections include the majority of intrinsic connections within area 3b; feedback connections from area 1, secondary somatosensory cortex (S2), parietal ventral area (PV), and other cortical areas; and thalamic inputs from the ventroposterior lateral nucleus (VPL). In addition, tracer injections in the reactivated hand region of area 3b labeled more neurons in the face and shoulder regions of area 3b than in normal monkeys, and injections in the face region of area 3b labeled more neurons in the hand region. Unexpectedly, the intrinsic connections within area 3b hand cortex were more widespread after incomplete dorsal column lesions (DCLs) than after a complete DCL. Although these additional connections were limited, these changes in connections may contribute to the reactivation process after injuries. J. Comp. Neurol. 524:1494-1526, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
| | - Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
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18
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Liao CC, DiCarlo GE, Gharbawie OA, Qi HX, Kaas JH. Spinal cord neuron inputs to the cuneate nucleus that partially survive dorsal column lesions: A pathway that could contribute to recovery after spinal cord injury. J Comp Neurol 2015; 523:2138-60. [PMID: 25845707 PMCID: PMC4575617 DOI: 10.1002/cne.23783] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 04/02/2015] [Accepted: 04/02/2015] [Indexed: 01/29/2023]
Abstract
Dorsal column lesions at a high cervical level deprive the cuneate nucleus and much of the somatosensory system of its major cutaneous inputs. Over weeks of recovery, much of the hand representations in the contralateral cortex are reactivated. One possibility for such cortical reactivation by hand afferents is that preserved second-order spinal cord neurons reach the cuneate nucleus through pathways that circumvent the dorsal column lesions, contributing to cortical reactivation in an increasingly effective manner over time. To evaluate this possibility, we first injected anatomical tracers into the cuneate nucleus and plotted the distributions of labeled spinal cord neurons and fibers in control monkeys. Large numbers of neurons in the dorsal horn of the cervical spinal cord were labeled, especially ipsilaterally in lamina IV. Labeled fibers were distributed in the cuneate fasciculus and lateral funiculus. In three other squirrel monkeys, unilateral dorsal column lesions were placed at the cervical segment 4 level and tracers were injected into the ipsilateral cuneate nucleus. Two weeks later, a largely unresponsive hand representation in contralateral somatosensory cortex confirmed the effectiveness of the dorsal column lesion. However, tracer injections in the cuneate nucleus labeled only about 5% of the normal number of dorsal horn neurons, mainly in lamina IV, below the level of lesions. Our results revealed a small second-order pathway to the cuneate nucleus that survives high cervical dorsal column lesions by traveling in the lateral funiculus. This could be important for cortical reactivation by hand afferents, and recovery of hand use.
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Affiliation(s)
- Chia-Chi Liao
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | | | - Omar A. Gharbawie
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Hui-Xin Qi
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Jon H. Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
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Moxon KA, Oliviero A, Aguilar J, Foffani G. Cortical reorganization after spinal cord injury: always for good? Neuroscience 2014; 283:78-94. [PMID: 24997269 DOI: 10.1016/j.neuroscience.2014.06.056] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/09/2014] [Accepted: 06/25/2014] [Indexed: 12/29/2022]
Abstract
Plasticity constitutes the basis of behavioral changes as a result of experience. It refers to neural network shaping and re-shaping at the global level and to synaptic contacts remodeling at the local level, either during learning or memory encoding, or as a result of acute or chronic pathological conditions. 'Plastic' brain reorganization after central nervous system lesions has a pivotal role in the recovery and rehabilitation of sensory and motor dysfunction, but can also be "maladaptive". Moreover, it is clear that brain reorganization is not a "static" phenomenon but rather a very dynamic process. Spinal cord injury immediately initiates a change in brain state and starts cortical reorganization. In the long term, the impact of injury - with or without accompanying therapy - on the brain is a complex balance between supraspinal reorganization and spinal recovery. The degree of cortical reorganization after spinal cord injury is highly variable, and can range from no reorganization (i.e. "silencing") to massive cortical remapping. This variability critically depends on the species, the age of the animal when the injury occurs, the time after the injury has occurred, and the behavioral activity and possible therapy regimes after the injury. We will briefly discuss these dependencies, trying to highlight their translational value. Overall, it is not only necessary to better understand how the brain can reorganize after injury with or without therapy, it is also necessary to clarify when and why brain reorganization can be either "good" or "bad" in terms of its clinical consequences. This information is critical in order to develop and optimize cost-effective therapies to maximize functional recovery while minimizing maladaptive states after spinal cord injury.
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Affiliation(s)
- K A Moxon
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
| | - A Oliviero
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain
| | - J Aguilar
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain
| | - G Foffani
- Hospital Nacional de Parapléjicos, SESCAM, Finca la Peraleda s/n, 45071 Toledo, Spain.
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Qi HX, Kaas JH, Reed JL. The reactivation of somatosensory cortex and behavioral recovery after sensory loss in mature primates. Front Syst Neurosci 2014; 8:84. [PMID: 24860443 PMCID: PMC4026759 DOI: 10.3389/fnsys.2014.00084] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 04/22/2014] [Indexed: 02/04/2023] Open
Abstract
In our experiments, we removed a major source of activation of somatosensory cortex in mature monkeys by unilaterally sectioning the sensory afferents in the dorsal columns of the spinal cord at a high cervical level. At this level, the ascending branches of tactile afferents from the hand are cut, while other branches of these afferents remain intact to terminate on neurons in the dorsal horn of the spinal cord. Immediately after such a lesion, the monkeys seem relatively unimpaired in locomotion and often use the forelimb, but further inspection reveals that they prefer to use the unaffected hand in reaching for food. In addition, systematic testing indicates that they make more errors in retrieving pieces of food, and start using visual inspection of the rotated hand to confirm the success of the grasping of the food. Such difficulties are not surprising as a complete dorsal column lesion totally deactivates the contralateral hand representation in primary somatosensory cortex (area 3b). However, hand use rapidly improves over the first post-lesion weeks, and much of the hand representational territory in contralateral area 3b is reactivated by inputs from the hand in roughly a normal somatotopic pattern. Quantitative measures of single neuron response properties reveal that reactivated neurons respond to tactile stimulation on the hand with high firing rates and only slightly longer latencies. We conclude that preserved dorsal column afferents after nearly complete lesions contribute to the reactivation of cortex and the recovery of the behavior, but second-order sensory pathways in the spinal cord may also play an important role. Our microelectrode recordings indicate that these preserved first-order, and second-order pathways are initially weak and largely ineffective in activating cortex, but they are potentiated during the recovery process. Therapies that would promote this potentiation could usefully enhance recovery after spinal cord injury.
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Affiliation(s)
- Hui-Xin Qi
- Department of Psychology, Vanderbilt University Nashville, TN, USA
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University Nashville, TN, USA
| | - Jamie L Reed
- Department of Psychology, Vanderbilt University Nashville, TN, USA
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