ACTIVITY PATTERNS IN INDIVIDUAL HINDLIMB PRIMARY AND SECONDARY MUSCLE-SPINDLE AFFERENTS DURING NORMAL MOVEMENTS IN UNRESTRAINED CATS
ACTIVITY PATTERNS IN INDIVIDUAL HINDLIMB PRIMARY AND SECONDARY MUSCLE-SPINDLE AFFERENTS DURING NORMAL MOVEMENTS IN UNRESTRAINED CATS
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DOI：
10.1152/jn.1979.42.2.420
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发表时间：
1979-01-01
影响因子：
2.5
通讯作者：
DUYSENS, J
中科院分区：
文献类型：
--
作者：
LOEB, GE;DUYSENS, J
在腰7节和骶1节背根神经节长期植入微电极丝，记录猫后肢原发性和继发性肌纺锤体传入神经的单位活动。单位可以可靠地记录数天，允许在各种正常的、不受限制的运动中，将它们的活动与相同的肌肉肌电图和长度进行比较。总的观察结果是，在初级和次级末梢中，根据涉及的肌肉类型和进行的运动类型，有广泛不同的活动模式。在行走过程中，在相似的步进循环中，给定主轴的活动通常是一致的。纺锤体活动调节与肌肉长度变化无明显关系，纺锤体活动明显受梭状运动的影响。在某些肌肉中，这种假设导致了。γ。-运动神经元可能与同名的- α非相激活。-运动神经元和更常规的。α。- γ。运动神经元coactivation。同时记录来自指长伸肌的2个纺锤波初级传入信号表明，同一块肌肉内的纺锤波可能有很大的不同。运动神经元。纺锤体次级末端似乎主要是步行时肌肉长度的被动指标，但在其他运动活动（如姿势变化和摇爪）中可能表现出明显的强烈的纺锤体运动调节。初级和次级末梢都经历了非常快速的放电速率调节，以响应假定的反射性诱导的输液收缩。纺锤体的梭形运动控制模式可能是针对特定的肌肉和正在执行的任务量身定制的，而不一定是由刚性的α - γ控制的。coactivation。
Chronically implanted microelectrode wires in the L[lumbar]7 and S[sacral]1 dorsal root ganglia were used to record unit activity from cat hindlimb primary and secondary muscle spindle afferents. Units could be reliably recorded for several days, permitting comparison of their activity with homonymous muscle EMG [electromyography] and length during a variety of normal, unrestrained movements. The general observation was that among both primary and secondary endings there was a broad range of different patterns of activity depending on the type of muscle involved and the type of movement performed. During walking, the activity of a given spindle primary was usually consistent among similar step cycles. Spindle activity modulation not apparently related to muscle length changes was apparently influenced by fusimotor activity. In certain muscles, this presumption led to the conclusion that .gamma.-motoneurons may be activated out of phase with homonymous .alpha.-motoneurons and by more conventional .alpha.-.gamma.-motoneuron coactivation. Simultaneous recordings of 2 spindle primary afferents from extensor digitorum longus indicated that spindles within the same muscle may differ considerably with respect to this presumed .gamma.-motoneuron drive. Spindle secondary endings appeared to be predominantly passive indicators of muscle length during walking, but could demonstrate apparently strong fusimotor modulation during other motor activities such as postural changes and paw shaking. Both primary and secondary endings underwent very rapid modulation of firing rates in response to presumed reflexly induced intrafusal contractions. The pattern of fusimotor control of spindles may be tailored to the specific muscle and task being performed, rather than necessarily dominated by rigid .alpha.-.gamma. coactivation.