Hypothalamic lesioned rats given haloperidol mimic the behavior of intact rats given haloperidol plus morphine

Lateral hypothalamic (LH) damage produces rats which exhibit sensory neglect, somnolence and akinesia, while ventromedial hypothalamic (VMH) damage produces rats which exhibit sensory hyperesponsiveness (Marshall and Teitelbaum, 1977). Rats with large lesions of both LH and VMH are somnolent and akinetic but hyperesponsive to touch. When given haloperidol (5 mg/kg) the LH-VMH-damaged rats adopt an actively maintained splayed out posture, in which the limbs are abducted and extended and the body lies flat on the ground. While in this posture, reflexes of postural stability, such as buttressing against a displacing force, are partially inhibited. These postural characteristics are similar to those of normal rats given haloperidol (5 mg/kg) plus morphine (20 mg/kg) (Pellis et al., 1986).