Mortin L I, Keifer J, Stein P S
J Neurophysiol. 1985 Jun;53(6):1501-16. doi: 10.1152/jn.1985.53.6.1501.
The scratch reflex is a motor task exhibited by the hindlimb of a turtle after complete transection of the spinal cord just posterior to the forelimb enlargement. The scratch is elicited by applying gentle tactile stimulation to a site innervated by spinal segments caudal to the level of the transection. During the scratch response, the ipsilateral hindlimb reaches toward and rubs against the stimulated site. Each scratch response consists of either a single rub or a rhythmic series of rubs. There are three types or "forms" of the scratch reflex in the spinal turtle: rostral scratch (previously termed the scratch reflex in Refs. 5, 43, 45), pocket scratch, and caudal scratch. We have characterized each scratch form according to which portion of the hindlimb is used to rub against the stimulated site. During a rostral scratch, the dorsum of the foot and/or toes is used to rub against the stimulated site. During a pocket scratch, the side of the thigh, knee, and/or calf is used to rub. During a caudal scratch, the heel or side of the foot is used to rub. Each scratch form has a distinct receptive field on the turtle shell and skin. A rhythmic scratch response to maintained tactile stimulation consists of as many as 10-25 cycles. We have divided each cycle of movement into a prerub, rub, and postrub phase. Extension of the knee joint occurs during the rub phase of each scratch cycle for all scratch forms. The timing of the extension phase of the knee joint movement within the protraction-retraction (flexion-extension) cycle of the hip joint is different for each form of the scratch. During a rostral scratch, extension of the knee joint occurs when the hip is protracted. During a pocket scratch, knee extension occurs when the hip is retracting. During a caudal scratch, knee extension occurs when the hip is retracted. The spinal turtle therefore shifts the timing of movements of a distal joint (knee) with respect to the timing of movements of a proximal joint (hip) to obtain appropriate scratching movements to different regions of the body. A narrow transition zone exists between the receptive field for one form of the scratch and the nearby receptive field for another form of the scratch. There is a rostral-pocket transition zone and caudal-pocket transition zone in the spinal turtle.(ABSTRACT TRUNCATED AT 400 WORDS)
搔抓反射是乌龟后肢在脊髓于前肢膨大后方完全横断后所表现出的一种运动任务。通过对横断水平以下脊髓节段所支配的部位施加轻柔的触觉刺激来引发搔抓动作。在搔抓反应过程中，同侧后肢会朝着受刺激部位伸展并摩擦该部位。每次搔抓反应由单次摩擦或一系列有节奏的摩擦组成。脊髓横断的乌龟存在三种类型或“形式”的搔抓反射：头端搔抓（以前在参考文献5、43、45中称为搔抓反射）、袋状搔抓和尾端搔抓。我们根据后肢用于摩擦受刺激部位的部分对每种搔抓形式进行了特征描述。在头端搔抓过程中，足背和/或脚趾用于摩擦受刺激部位。在袋状搔抓过程中，大腿侧面、膝盖和/或小腿用于摩擦。在尾端搔抓过程中，脚跟或足侧用于摩擦。每种搔抓形式在龟壳和皮肤上都有独特的感受野。对持续触觉刺激的有节奏搔抓反应由多达10 - 25个周期组成。我们将每个运动周期分为摩擦前、摩擦和摩擦后阶段。对于所有搔抓形式，膝关节伸展发生在每个搔抓周期的摩擦阶段。髋关节的前伸 - 后缩（屈曲 - 伸展）周期内，膝关节运动伸展阶段的时间对于每种搔抓形式是不同的。在头端搔抓过程中，当髋关节前伸时膝关节伸展。在袋状搔抓过程中，当髋关节后缩时膝关节伸展。在尾端搔抓过程中，当髋关节后缩时膝关节伸展。因此，脊髓横断的乌龟会相对于近端关节（髋关节）的运动时间来改变远端关节（膝关节）的运动时间，以获得针对身体不同区域的适当搔抓动作。一种搔抓形式的感受野与另一种搔抓形式的附近感受野之间存在一个狭窄的过渡区。脊髓横断的乌龟存在一个头端 - 袋状过渡区和尾端 - 袋状过渡区。（摘要截选至400字）
