Presynaptic inhibition and homosynaptic depression -: A comparison between lower and upper limbs in normal human subjects and patients with hemiplegia
Presynaptic inhibition and homosynaptic depression -: A comparison between lower and upper limbs in normal human subjects and patients with hemiplegia
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DOI：
10.1093/brain/123.8.1688
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发表时间：
2000-08-01
期刊：
影响因子：
14.5
通讯作者：
Raoul, S
中科院分区：
文献类型：
--
作者：
Aymard, C;Katz, R;Raoul, S
比较了不同人群两侧上肢和下肢 Ia 末端的突触前抑制和 Ia 纤维运动神经元 (MN) 突触的激活后抑制：49 名痉挛性偏瘫患者 [主要是大脑中动脉 (MCA) 区域的病变]，2 名四肢瘫痪患者和 35 名健康受试者。使用比目鱼肌和桡侧腕屈肌 (FCR) H 反射的 D1 抑制来评估突触前抑制，该反射由施加到供应拮抗肌的神经的电刺激引起，并通过改变两个连续 H 反射之间的时间间隔来探索激活后抑制。在正常受试者中，突触前 Ia 抑制量、同突触抑制或 H-max/M-max 比率未发现左右不对称。在 MCA 区域病变患者的偏瘫侧，比目鱼肌中的 H-max/M-max 比值显着增加，但 FCR 中没有显着增加。 Ia 末端的突触前抑制在偏瘫侧的颈部水平显着降低，但在未受影响的一侧也显着降低，但在腰椎水平没有变化。同突触抑制在偏瘫侧的颈椎和腰椎水平也同样减少，但在未受影响的一侧没有改变。有人认为 Ia 末端突触前抑制的减少更多的是与痉挛相关，而不是其背后的机制。激活后抑郁的减少很可能导致以痉挛为特征的牵张反射的夸大，这可能是运动损伤后 Ia 传入神经和 MN 激活模式变化的结果。
Presynaptic inhibition of Ia terminals and postactivation depression at the Ia fibre-motor neuron (MN) synapses were compared in the upper and lower limbs of both sides in subjects from different populations: 49 spastic patients with hemiplegia [mainly with a lesion in the middle cerebral artery (MCA) area], two tetraplegics and 35 healthy subjects. Presynaptic inhibition was assessed using D1 inhibition of the soleus and the flexor carpi radialis (FCR) H reflexes elicited by electrical stimuli applied to the nerve supplying antagonistic muscles, and postactivation depression was explored by varying the time interval between two consecutive H reflexes. In normal subjects no right-left asymmetry was found in the amount of presynaptic Ia inhibition, homosynaptic depression or the H-max/M-max ratio. In the hemiplegic side of patients with MCA area lesions, the H-max/M-max ratio was significantly increased in the soleus but not in the FCR, Presynaptic inhibition of Ia terminals, which was significantly reduced at the cervical level on the hemiplegic side land also, hut to a lesser extent, on the unaffected side), was unchanged at the lumbar level. Homosynaptic depression was similarly reduced at the cervical and lumbar levels on the hemiplegic side but not modified on the unaffected side, It is argued that the decrease in presynaptic inhibition of Ia terminals is more a correlate of spasticity than a mechanism underlying it. The decrease in postactivation depression, which very probably contributes to the exaggeration of the stretch reflex characterizing spasticity, might be a consequence of the changes in the pattern of activation of Ia afferents and MNs following the motor impairment.