MONOSYNAPTIC AND DORSAL-ROOT REFLEXES DURING LOCOMOTION IN NORMAL AND THALAMIC CATS
MONOSYNAPTIC AND DORSAL-ROOT REFLEXES DURING LOCOMOTION IN NORMAL AND THALAMIC CATS
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DOI：
10.1152/jn.1990.63.6.1467
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发表时间：
1990-06-01
影响因子：
2.5
通讯作者：
MARKS, WB
中科院分区：
文献类型：
--
作者：
DUENAS, SH;LOEB, GE;MARKS, WB
1.在正常和丘脑步行猫的肌肉神经的电刺激，通过长期植入电极产生肌电图（EMG）和神经描记反应，调制幅度取决于步骤周期的阶段。这些反应进行了检查，为可能的迹象，初级传入去极化（PAD）的影响，在步进。2.在正常猫跑台运动过程中，记录了刺激腓肠肌外侧（LG）和内侧（MG）神经所产生的单突触反射（MSR）。这些heteropathic MSR反应是最大的立场（伸肌）阶段。3.在相同的动物中，去大脑后，在自发运动过程中使用相同的刺激和记录部位发生了类似的调节异侧踝伸肌MSR。4.在正常猫和丘脑猫中，刺激另一块肌肉神经后，从LG或MG神经记录的神经电反应幅度随步进相位而变化，但不平行于在同一肌肉中测量的EMG幅度的MSR的变化。神经反应在步周期的屈曲阶段期间最大，并且具有0.6-1.0 ms的计算的中枢潜伏期。这些被解释为由大口径传入神经纤维中的逆向活动引起（即，背根反射）。5.自发逆向活动切断L7背根纤维小腿三头肌观察丘脑猫在运动的情节，并密切相关的屈曲相EMG活动在半腱肌，双功能肌肉。6.在去大脑猫，通过刺激隐神经和胫后神经，在L4-L7背根的切断细丝中产生背根反射（DRR）。这些DRR在运动过程中总是比在休息时小，在屈曲阶段最小。7.因此，通过刺激异源肌神经在肌神经中产生的短潜伏期逆向活动似乎是在屈曲阶段期间去极化接近阈值的I组末端分支中产生的DRR。这种PAD可以解释MSR的变化，这些变化并不总是与背景EMG振幅所表现的运动池的募集水平平行。
1. In normal and thalamic walking cats electrical stimulation of muscle nerves via chronically implanted electrodes produced electromyographic (EMG) and neurographic responses that were modulated in amplitude depending on the phase of the step cycle. These responses were examined for possible indications of effects of primary afferent depolarization (PAD) during stepping. 2. Monosynaptic reflexes (MSRs) produced by stimulating the lateral gastrocnemius (LG) and medial gastrocnemius (MG) nerves were recorded as EMGs in MG or LG muscles during treadmill locomotion in normal cats. These heteronymous MSR responses were greatest during the stance (extensor) phase. 3. In the same animals, after decerebration, similar modulation of the heteronymous ankle extensor MSRs occurred during spontaneous locomotion with the use of the same stimulus and recording sites. 4. In both normal and thalamic cats the amplitude of neurogram responses recorded from LG or MG nerve after stimulation of the other muscle nerve varied with phase of stepping but did not parallel the variations of the MSR measured as EMG amplitude in the same muscle. The nerve responses were largest during the flexion phase of the step cycle and had a calculated central latency of 0.6-1.0 ms. These are interpreted as arising from antidromic activity in large-caliber afferent nerve fibers (i.e., dorsal root reflexes). 5. Spontaneous antidromic activity in severed L7 dorsal rootlet fibers to triceps surae was observed in the thalamic cats during episodes of locomotion and was closely correlated with flexion phase EMG activity in semitendinosus, a bifunctional muscle. 6. In decerebrate cats, dorsal root reflexes (DRRs) in severed filaments of L4-L7 dorsal roots were produced by stimulation of saphenous and posterior tibial nerves. These DRRs were always smaller during locomotion than during rest and were smallest during the flexion phase. 7. The short-latency antidromic activity produced in muscle nerves by stimulating heteronymous muscle nerves thus appears to be a DRR produced in Group I terminal arborizations that are depolarized close to threshold during the flexion phase. Such PAD could account for changes in the MSR that do not always parallel the levels of recruitment of the motor pools as manifest by background EMG amplitude.