1. Hormones, the Brain, and Behavior

2. Types of Chemical Communication Synaptic (neurotransmitters) ENDOCRINE (hormones) -Released in bloodstream -act at distance (target organs) -Slow action Other types of communication: Exocrine, Pheromone Some substances (e.g., adrenaline) act both as NT and hormone

3. Glands of the Endocrine System

4. (CRH) _ _ The HPA Axis – the key system controlling stress response Target organs Glucocorticoids i.e. cortisol

5. Glucocorticoids (stress) Short term effect; –Mobilize energy stores Long term effect Hippocampal cell death

6. How are hormones controlled? The hypothalamus controls the pituitary gland The pituitary has two major divisions –Anterior: (aka hypophysis). It’s connected to the hypothalamus via blood vessels and is controlled by hormones released from the hypothalamus. –Posterior. Hypothalamic neurons project axons that secrete oxytocin (and vasopressin) into capillaries of the posterior pituitary.

10. Hormone release affects behavior… Estrogens (ovaries)  female sexual behavior. Androgens (testes)  male sexual behavior. Insulin (pancreas)  food intake. Epinephrine (adrenal)  arousal and alertness. Oxytocin (posterior pituitary)  parental behavior. …and behavior can affect hormone release Fear or surprise  epinephrine Smell of food  insulin secretion Nipple stimulation or crying baby  oxytocin release and milk letdown. Sexual intimacy  oxytocin, among others

11. Endocrine manipulations are quite common in our society and have a long history. Castration of male animals: Why do it? It’s easy! Positive effects on behavior May improve physical properties Population control We don’t need a whole bunch of males anyway!!

12. Actually, there’s a long history of castrating men –eunuchs Punishment “Testosterone-sensitive” jobs –guarding the harem Castrati –male sopranos –until late 1700’s Over a million eunuchs in contemporary India – mostly by choice.

13. The first experimental endocrinology was done by A.A. Berthoud – 1840s Caponization of roosters Normal males: red comb, colorful plumage, struts, fights, mates, and crows Castrated before maturity: no comb, no strut, no fight, no crow, no mates Castrated before maturity and testes implanted into abdomen: just like normals !