Читать книгу Neurology - Charles H. Clarke - Страница 55

Aggression or docility are features of lateral/ventromedial hypothalamic imbalance. Obese animals with ventromedial lesions become aggressive. Underweight, ventromedially stimulated animals are docile. Hunger stimulates arousal. Maybe this explains why some people become grumpy when they are not fed at the time they expect to be.

Sexual arousal: specific neurones (INAH3 cells) in each preoptic nucleus are more numerous in males than in females. This is an area rich in androgen receptors, activated by testosterone and induces male sexual activity. In females, neurones rich in oestrogen receptors are found in the ventromedial nucleus: stimulation induces sexual arousal.

Sleep–wake cycles are set by the suprachiasmatic nucleus via pineal gland connections. Arousal is mediated via richly histaminergic neurones in the posterior hypothalamus (the tuberomammillary nucleus). These project widely (medial forebrain bundle, cortex, brainstem, cord). Hypersomnolence in Man is seen when the posterior hypothalamus is damaged bilaterally.

Memory: the mammillary bodies are stations on Papez’s circuit (fornix → mammillary bodies → mammillothalamic tract → anterior nucleus of thalamus, Chapter 22). Mammillary body destruction produces a dramatic amnestic syndrome.