Adaptive motor cortex plasticity following grip reconstruction in individuals with tetraplegia.
Adaptive motor cortex plasticity following grip reconstruction in individuals with tetraplegia.
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DOI：
10.3233/rnn-170775
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发表时间：
2018
影响因子：
2.8
通讯作者：
Björnsdotter M
中科院分区：
文献类型：
--
作者：
Bunketorp Käll L;Cooper RJ;Wangdell J;Fridén J;Björnsdotter M
肌腱移植是一种恢复颈脊髓损伤（SCI）患者上肢运动控制的手术技术，并提供了一个罕见的窗口，了解手臂和手部功能恢复后的皮质神经可塑性。在这里，我们的目的是研究肌腱转移后重建拇指屈曲自主运动控制的神经可塑性机制。我们使用功能性磁共振成像（fMRI）来验证一个假设，即肌腱移植后肢体控制的恢复是通过激活该肢体的初级运动皮层区域来介导的。我们检查了6例在瑞典Sahlgrenska大学医院接受右侧手术重建的四肢瘫痪患者。所有患者均为右撇子男性，脊髓损伤位于C6或C7水平，平均年龄为40岁（范围= 31-48）。自SCI以来的平均时间为13年（范围为6-26年）。选取6名性别和年龄匹配的右撇子作为对照（平均年龄39岁，范围29-46岁）。通过手术将一个功能正常的肘关节屈肌（肱桡肌）转移到瘫痪的拇指屈肌（拇长屈肌），可以恢复患者的活动拇指屈曲。我们研究了等距右肘屈曲和键捏时的fMRI反应，并检查了手术后至少一年左半球躯体运动皮层内的皮层表征。肘关节屈曲引起的皮质激活在患者和对照组参与者之间的地形上没有差异。然而，与对照组相比，患者的拇指皮质屈曲激活与肘关节屈曲激活在地形上并没有明显不同。这一结果反对地形重组，其中拇指区域恢复拇指控制手术肌腱转移。相反，我们的研究结果表明了一种神经可塑性机制，在这种机制中，以前专门用于肘关节屈曲的运动皮层资源适应了对拇指的控制。
Tendon transfer is a surgical technique for restoring upper limb motor control in patients with cervical spinal cord injuries (SCI), and offers a rare window into cortical neuroplasticity following regained arm and hand function. Here, we aimed to examine neuroplasticity mechanisms related to re-established voluntary motor control of thumb flexion following tendon transfer. We used functional Magnetic Resonance Imaging (fMRI) to test the hypothesis that restored limb control following tendon transfer is mediated by activation of that limb’s area of the primary motor cortex. We examined six individuals with tetraplegia who underwent right-sided surgical grip reconstruction at Sahlgrenska University Hospital, Sweden. All were right-handed males, with a SCI at the C6 or C7 level, and a mean age of 40 years (range = 31–48). The average number of years elapsed since the SCI was 13 (range = 6–26). Six right-handed gender- and age-matched control subjects were included (mean age 39 years, range = 29–46). Restoration of active thumb flexion in patients was achieved by surgical transfer of one of the functioning elbow flexors (brachioradialis), to the paralyzed thumb flexor (flexor pollicis longus). We studied fMRI responses to isometric right-sided elbow flexion and key pinch, and examined the cortical representations within the left hemisphere somatomotor cortex a minimum of one year after surgery. Cortical activations elicited by elbow flexion did not differ in topography between patients and control participants. However, in contrast to control participants, patients’ cortical thumb flexion activations were not topographically distinct from their elbow flexion activations. This result speaks against a topographic reorganization in which the thumb region regains thumb control following surgical tendon transfer. Instead, our findings suggest a neuroplastic mechanism in which motor cortex resources previously dedicated to elbow flexion adapt to control the thumb.