Andersen Ole K, Spaich Erika G, Madeleine Pascal, Arendt-Nielsen Lars
Department of Health Science and Technology, Center for Sensory-Motor Interaction, Aalborg University, Fredrik Bajers Vej 7, D3, DK-9220 Aalborg, Denmark.
Brain Res. 2005 May 3;1042(2):194-204. doi: 10.1016/j.brainres.2005.02.039.
Dynamic changes in the topography of the human withdrawal reflex receptive fields (RRF) were assessed by repetitive painful stimuli in 15 healthy subjects. A train of five electrical stimuli was delivered at a frequency of 3 Hz (total train duration 1.33 s). The train was delivered in random order to 10 electrode sites on the sole of the foot. Reflexes were recorded from tibialis anterior, soleus, vastus lateralis, biceps femoris, and iliopsoas (IL). The RRF changes during the stimulus train were assessed during standing with even support on both legs and while seated. The degree of temporal summation was depending on stimulation site. At the most sensitive part of the RRF, a statistically significant increase in reflex size was seen after two stimuli while four stimuli were needed to observe reflex facilitation at less sensitive electrode sites. Hence, the region from which reflexes could be evoked using the same stimulus intensity became larger through the train, that is, the RRF was gradually expanding. Reflexes evoked by stimuli four and five were of the same size. No reflex facilitation was seen at other stimulus sites outside the RRF. In all muscles except in IL, the largest reflexes were evoked when the subjects were standing. In the ankle joint, the main withdrawal pattern consisted of plantar flexion and inversion when the subjects were standing while dorsi-flexion was prevalent in the sitting position. Up to 35 degrees of knee and hip flexion were evoked often leading to a lift of the foot from the floor during standing. In conclusion, a gradual expansion of the RRF was seen in all muscles during the stimulus train. Furthermore, the motor programme task controls the reflex sensitivity within the reflex receptive field and, hence, the sensitivity of the temporal summation mechanism.
通过对15名健康受试者施加重复性疼痛刺激，评估了人体退缩反射感受野（RRF）地形的动态变化。以3 Hz的频率施加一串五个电刺激（总串持续时间1.33秒）。该串刺激以随机顺序施加于足底的10个电极部位。从胫骨前肌、比目鱼肌、股外侧肌、股二头肌和髂腰肌（IL）记录反射。在双腿均匀支撑站立和坐着时，评估刺激串期间RRF的变化。时间总和的程度取决于刺激部位。在RRF最敏感的部位，两次刺激后反射大小有统计学意义的增加，而在较不敏感的电极部位则需要四次刺激才能观察到反射易化。因此，使用相同刺激强度可诱发反射的区域在刺激串过程中逐渐变大，即RRF逐渐扩大。由第四和第五次刺激诱发的反射大小相同。在RRF之外的其他刺激部位未观察到反射易化。除IL外，在所有肌肉中，受试者站立时诱发的反射最大。在踝关节，受试者站立时主要的退缩模式包括跖屈和内翻，而坐位时背屈较为普遍。站立时常常诱发高达35度的膝关节和髋关节屈曲，导致脚离开地面。总之，在刺激串期间，所有肌肉的RRF均出现逐渐扩大。此外，运动程序任务控制着反射感受野内的反射敏感性，从而控制时间总和机制的敏感性。
