FUNCTIONAL-ORGANIZATION WITHIN THE MEDULLARY RETICULAR-FORMATION OF INTACT UNANESTHETIZED CAT .2. ELECTROMYOGRAPHIC ACTIVITY EVOKED BY MICROSTIMULATION
FUNCTIONAL-ORGANIZATION WITHIN THE MEDULLARY RETICULAR-FORMATION OF INTACT UNANESTHETIZED CAT .2. ELECTROMYOGRAPHIC ACTIVITY EVOKED BY MICROSTIMULATION
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DOI：
10.1152/jn.1990.64.3.782
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发表时间：
1990-09-01
影响因子：
2.5
通讯作者：
ROSSIGNOL, S
中科院分区：
文献类型：
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作者：
DREW, T;ROSSIGNOL, S
1.本研究探讨了详细的组织髓质网状结构（MRF）所揭示的微刺激（330 Hz和35微安或更低的0.2 ms持续时间脉冲的33 ms序列）。记录四肢屈肌和伸肌的刺激锁定肌电图（EMG）反应，以及双侧颈部和背部的肌肉，在刺激形成前述文章基础的相同592个位点期间。2.每组肌肉的反应阈值不同，平均而言，颈部肌肉在最低电流范围13.8-16.5微安时被激活;前肢肌肉在16.9-17.9微安时被激活;背部肌肉在25.4-25.7微安时被激活;后肢肌肉在21.1-25.7微安时被激活。3.然而，MRF内的刺激仅引起头部向受刺激侧的运动（前一篇文章），EMG反应的分析显示颈部肌肉经常双侧激活。同样，即使刺激主要产生同侧肘关节屈曲和对侧肘关节伸展，大多数位点引起这些关节的拮抗肌的共同收缩。也经常观察到后肢的共同收缩。拮抗肌的相互激活频率较低，但在同侧前肢以及在两个后肢中观察到;它从未在对侧前肢中观察到。4.虽然兴奋性反应，观察到从广泛的区域为所有的肌肉研究中，这些地区的MRF引起的最强的反应，在每块肌肉表现出很大程度的隔离。同侧前肢的肌肉最强烈地激活从rostrodoral MRF，而对侧前肢的肌肉最强烈地受到尾腹刺激的影响。后肢的肌肉更强烈地激活从喙脑干，虽然有一些例外。在轴向肌肉的反应引起广泛的区域的脑干，但进一步集中在尾部比四肢肌肉。5.兴奋性反应比抑制性反应普遍得多，并且从MRF的所有区域诱发，包括最尾侧和腹侧区域。平均而言，每个轨迹的最短潜伏期反应如下：颈部6.6-8.8 ms;前肢11.2-13.4 ms;背部13.8-14.2 ms;后肢15.9-17.2 ms。抑制反应也引起广泛分布的区域，这是混合在那些位点引起兴奋性反应。（400字处截断摘要）
1. The present study has examined the detailed organization of the medullary reticular formation (MRF) as revealed by microstimulation (33-ms trains of 0.2-ms duration pulses at 330 Hz and 35 microA or less) in the intact, chronically implanted, unanesthetized cat. Stimulus-locked electromyographic (EMG) responses were recorded from flexors and extensors of each of the four limbs, as well as bilaterally from muscles of the neck and back, during stimulation of the same 592 loci that formed the basis of the preceding article. 2. The thresholds of the responses were different for each group of muscles, with, on the average, the neck muscles being activated at the lowest range of currents, 13.8-16.5 microA; forelimb muscles at 16.9-17.9 microA; back muscles at 25.4-25.7 microA; and hindlimb muscles at 21.1-25.7 microA. 3. Whereas stimulation within the MRF evoked movement of the head only to the stimulated side (preceding article), analysis of the EMG responses showed there was frequently bilateral activation of the neck muscles. Similarly, even though stimulation produced predominantly ipsilateral elbow flexion and contralateral elbow extension, most loci caused cocontraction of antagonistic muscles at these joints. Cocontraction was also frequently observed for the hindlimbs. Reciprocal activation of antagonistic muscles was less frequent but was observed in the ipsilateral forelimb as well as in both hindlimbs; it was never observed in the contralateral forelimb. 4. Although excitatory responses were observed from widespread regions for all of the muscles under study, those regions of the MRF that evoked the strongest responses in each muscle showed a large degree of segregation. Muscles of the ipsilateral forelimb were most strongly activated from the rostrodorsal MRF, whereas muscles of the contralateral forelimb were most strongly effected by stimulation caudoventrally. Muscles of the hindlimbs were more strongly activated from the rostral brain stem, although with some exceptions. Responses in axial muscles were evoked from widespread regions of the brain stem but were concentrated further caudally than were the limb muscles. 5. Excitatory responses were much more prevalent than inhibitory responses and were evoked from all regions of the MRF, including the most caudal and ventral areas. The shortest latency responses in each track were, on the average, as follows: 6.6-8.8 ms for the neck; 11.2-13.4 ms for the forelimbs; 13.8-14.2 ms for the back; and 15.9-17.2 ms for the hindlimbs. Inhibitory responses were also evoked from widely distributed regions, which were intermingled with those loci evoking excitatory responses.(ABSTRACT TRUNCATED AT 400 WORDS)