A i.e.Preoptic nucleus - Sexual behavior is integrated in anterior-ventral hypothalamusQ; plus piriform coex (in males only) - Ganong - Sexual drive can be stimulated from several areas of hypothalamus, especially the most anterior and most posterior poions of hypothalamusQ (Guyton) - Medial preoptic area (MPOA) or the most anterior poion of hypothalamus is most impoant integrative nucleus involved in sexual behavior regulation of males in all veebratesQ. It integrates the male sexual behavior by receiving all indirect inputs from every sensory organ and sends efferents to structures that are critical for initiation and patterning of copulation. Therefore, stimulation of MPOA enhances sexual activity in males, whereas its damage consistently impairs male sexual behavior. Integrating Areas of Hypothalamus Function Anterior hypothalamus (response to heat), Temprature regulation (anteriorly Posterior hypothalamus (response to cold) hot, posteriorly cold) Suprachiasmatic nuclei Control of circadian body rhythm Punishment centers (esp periventricular zone of hypothalamus adjacent to 3rd ventricle, lateral Defensive reactions (fear, anger, rage, punishment, fighting)= hypothalamus & central grey area of mesencephalon) are stimulatory and ventromedial nuclei of hypothalamus, hippocampi, anterior limbic coex (esp anterior cingulate gyri and subcallosal gyri) are inhibitory to fear (punishment) Unpleasant sensation (Aversion) Reward centers locatd along the course of medial Calmness (Placidity, tameness & forebrain bundleQ especially in lateral and ventromedial tranquility) = Pleasant sensation nuclei of hypothalamus are self stimulatory (Reward or satisfaction) Appetitive Behavior Lateral (superior) hypothalamusQ Thirst Lateral hypothalamus activity level Hunger (eating) & increased Venteromedial nucleusQ, arcuate & paraventricular nuclei Satiety (Decreased eating) & tranquility Anterior ventral hypothalamus; most anterior (medial preoptic area=MPOA) & most posterior poions of hypothalamusQ; piriform coex (in males only) Sexual drive Neuroendocrinal control of Preoptic area FSH & LH Gn RH Supraoptic & paraventricular nuclei Vasopressin, Oxytocin Paraventricular nuclei TSH (thyrotropin) TRH ACTH & [3- lipotropin 03-LPH) CRH Paraventricular nucleus and arcuate nucleus GH somatostatin & GRH Arcuate nucleus; (hypothalamus inhibits secretion) Prolactin PIH & PRH Dorsal & posterior hypothalamus Catecholamines