Selective activation of human finger muscles after stroke or amputation.
Selective activation of human finger muscles after stroke or amputation.
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DOI：
10.1007/978-0-387-77064-2_30
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发表时间：
2009
影响因子：
--
通讯作者：
Sirigu, A.
中科院分区：
文献类型：
--
作者：
Schieber, Marc H.;Lang, C. E.;Reilly, K. T.;MeNulty, P.;Sirigu, A.
人类手的个性化手指运动需要选择性地激活特定的肌肉组。这种选择性激活主要由运动皮质通过皮质脊髓束控制。因此，当损伤损害皮质脊髓束时，这种选择性会丧失吗？或者当截肢后运动皮质重新组织时？我们研究了正常人和由腔隙性中风引起的纯运动性偏瘫基本康复的患者的手指运动，腔隙性中风损害了皮质脊髓束，而不影响其他通路。即使在从这些中风中实质性恢复后，手指运动的个性化仍然减少--包括手指的屈曲/伸展和内收/外展运动。中风受试者恢复了在正常范围内移动指示的手指的能力，但其他手指的无意运动增加了。这一增加并不是由于手指的被动生物力学耦合的改变造成的。相反，移动预定手指的肌肉的自愿收缩伴随着作用于额外手指的肌肉的不适当收缩。这些观察表明，正常的皮质脊髓系统不仅通过选择性地激活某些肌肉来产生个性化的手指运动，还通过在自愿努力移动给定的手指时抑制其他肌肉的激活来产生个性化的手指运动。在另一项单独的实验中，正常受试者通过手腕处的缺血神经阻滞造成可逆性截肢。在这些情况下，内在肌肉的运动输出和感觉输入都会受阻，从而有效地将手从神经系统中截断。但弯曲和伸展手指的长的外在肌肉通常仍处于神经支配状态，因此指尖仍然可以产生屈曲力。在由缺血神经阻滞造成的可逆性截肢过程中，受试者激活外在肌肉的细分和在个别指尖施加屈曲力的能力继续显示出基本上正常的选择性。因此，截肢后剩余肌肉的自主激活仍然是选择性的，尽管截肢的手失去了感觉输入，初级运动皮质也进行了重组。因此，在截肢后的皮质重组过程中，手指肌肉的自主运动输出模式可能不会丢失。因此，我们检查了肘部以上截肢者残肢肌肉的活动，这些截肢者没有剩余的手部肌肉。幻手的不同运动在剩余的近端肌肉中伴随着不同的EMG模式，与与幻肘运动相关的EMG模式不同。我们推断，通常控制截肢后手指运动的自主运动输出模式可能会转向剩余的近端肌肉。
Individuated finger movements of the human hand require selective activation of particular sets of muscles. Such selective activation is controlled primarily by the motor cortex via the corticospinal tract. Is this selectivity therefore lost when lesions damage the corticospinal tract? Or when the motor cortex reorganizes after amputation? We studied finger movements in normal human subjects and in patients who had recovered substantially from pure motor hemiparesis caused by lacunar strokes, which damage the corticospinal tract without affecting other pathways. Even after substantial recovery from these strokes, individuation of finger movements remained reduced— both for flexion/extension and for adduction/abduction motion of the fingers. Stroke subjects regained the ability to move the instructed digit through a normal range, but unintentional motion of other digits was increased. This increase did not result from a change in the passive biomechanical coupling of the fingers. Rather, voluntary contractions of muscles that move the intended digit were accompanied by inappropriate contractions in muscles acting on additional digits. These observations suggest that the normal corticospinal system produces individuated finger movements not only by selectively activating certain muscles, but also by suppressing activation of other muscles during voluntary effort to move a given digit. In a separate experiment, reversible amputation of the hand was produced in normal subjects by ischemic nerve block at the wrist. Motor output to the intrinsic muscles and sensory input both become blocked under these conditions, effectively amputating the hand from the nervous system. But the long extrinsic muscles that flex and extend the digits remain normally innervated, and thus flexion forces still can be generated at the fingertips. During reversible amputation of the hand produced by ischemic nerve block, the ability of subjects to activate subdivisions of extrinsic muscles and to exert flexion force at individual fingertips continued to show essentially normal selectivity. Voluntary activation of the remaining muscles thus continues to be selective after amputation, in spite of both the loss of sensory input from the amputated hand, and reorganization within the primary motor cortex. During cortical reorganization after amputation, then, voluntary patterns of motor output intended for finger muscles may not be lost. We therefore examined activity in the stump muscles of above-elbow amputees, who have no remaining hand muscles. Different movements of the phantom hand were accompanied by different patterns of EMG in remaining proximal muscles, distinct from the EMG patterns associated with movement of the phantom elbow. We infer that voluntary motor output patterns that normally control finger movements after amputation may become diverted to remaining proximal muscles.
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影响因子：
14.5
作者：
COHEN, LG;BANDINELLI, S;HALLETT, M
通讯作者：
HALLETT, M
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Lang, CE;Schieber, MH
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Gandevia, SC