Effects of body position on crossed extension reflex in decerebrate cat: rectus femoris is more sensitive than is vastus medialis

Physiological stimuli which increase postural extensor tone also excitability of the crossed extension reflex (CER). We report here that such stimuli increase excitability of the CER recorded from rectus femoris (RF) more than that of vastus medialis (VM). The difference might reflect an important role of the biarticular actions of RF, which is also a weak hip flexor, in stabilizing the hip as well as extending the knee during maintenance of posture.