'Axial apraxia' in labyrinthectomized lateral hypothalamic-damaged rats.

Contact righting, that is, turning from a recumbent position to prone, is abolished for a few days after large electrolytic lesions of the lateral hypothalamus. With recovery, contact righting reappears, but does so in a distinct manner. At first the body is righted by backleg movements, in the absence of any active axial rotation. Later, righting switches from back to front, so that righting begins in the shoulders and then proceeds to the pelvis. Such righting is achieved by axial rotation, that is, the limbs are carried by the torso, rather than vice versa. Labyrinthectomy, when combined with lateral hypothalamic (LH) damage, slows this recovery (now taking as long as 3 weeks), and reveals many intermediate stages of contact-righting. The absence of axial rotation in the early stages of recovery from combined LH damage and labyrinthectomy is compared to the 'axial apraxia' seen in some parkinsonian patients.