Somnolence, akinesia, and sensory activation of motivated behavior in the lateral hypothalamic syndrome.

After lateral hypothalamic damage in rats, somnolence, akinesia, and sensory neglect combine to produce complete aphagia. Only simple automatisms (such as grooming, chewing, licking) are present, but intense stimuli can activate more complex actions (walking, orientation, swimming). In the anorexic stage, tactile stimuli dominate in steering locomotion and "spontaneous" locomotion depends on activation from the empty stomach.