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1. Chapter 17 Sex and the Brain
2. I. Introduction to Reproductive System Review pp 548-560
3. II. Voles A. Prairie voles (17.9)
1. Intense mating period
2. Permanent mate
3. Shared care of young
4. II. Voles B. Montane voles
1. Live singly
2. Promiscuis
3. Only female cares for young and only for minimal amount of time
5. II. Voles C. Oxytocin and vasopressin (17.10color)
1. Receptor distribution varies between voles
[cause-effect?]
http://exn.ca/news/images/19990208-eceptorbig.gif
6. II. Voles C. Oxytocin and vasopressin
2. Female montane vole brain resembles prairie vole receptors during child rearing
3. When prairie voles mate
a. incr vasopressin in males
b. incr oxytocin in females
7. II. Voles (prairie) C. Oxytocin and vasopressin
4. If vasopressin antagonist given just before mating, male does not form a long term relationship
5. If male is given vasopressin when first exposed to a female, he forms a strong preference for her
6. Similarly, oxytocin is necessary for females to form long term relationship
8. II. Voles (prairie) C. Oxytocin and vasopressin
7. During child rearing
a. vasopressin incr males fathering role
b. oxytocin incr females mothering role
8. Giving vasopressin or oxytocin to montane voles does not affect behavior
a. perhaps receptors not present or distribution is different
[cause-effect?]
9. II. Sexual Dimorphisms A. Controvery (human brains)
1. Measurement techniques (17.12)
2. Sampling
3. Significance
4. Individual variation
5. Replication
6. Nature vs. nurture
SDN: male 5x vs. female
10. II. Sexual Dimorphisms B. Sex Hormones / Steroids and the Brain
1. Membrane bound responses
a. rapid
b. effects
1) membrane potential
2) transmitter receptor
3) transmitter release
11. II. Sexual Dimorphisms B. Sex Hormones / Steroids and the Brain
2. Intracytoplasmic receptors
a. slower change
b. longer lasting change
c. e.g., promote/inhibit transcription
d. analagous to NT receptors
12. II. Sexual Dimorphisms B. Sex Hormones / Steroids and the Brain
3. Effects of age
a. organizational effects
1) during development
2) long term
3) trigger development of male/female gonads
4) brain areas (?)
13. II. Sexual Dimorphisms B. Sex Hormones / Steroids and the Brain
b. activational effects
1) after development/puberty
2) temporary
3) triggers behavior
c. nature vs. nurture
14. II. Sexual Dimorphisms B. Sex Hormones / Steroids and the Brain
4. Estrogen and excitability
a. female rats hippocampal dendritic spines cycle with estrous cycle (plasticity)
b. directly proportional (17.15)
c. control: maintain low estrogen, administer estrogen, count spines
15. II. Sexual Dimorphisms B. Sex Hormones / Steroids and the Brain
d. hippocampus more excitable with incr dendritic spines (17.16)
e. incr spines directly proportional with excitatory synapses
f. incr spines directly proportional with incr NMDA receptors (excitatory)
16. II. Sexual Dimorphisms B. Sex Hormones / Steroids and the Brain
g. mechanism (?)
1) estradiol receptor in inhibitory neurons
2) estradiol causes decr GABA
3) causes decr inhibition
4) causes incr neuronal activity
5) somehow causes incr dendritic spines [Hebbian synapses?, plasticity?]
17. II. Sexual Dimorphisms B. Sex Hormones / Steroids and the Brain
h. epilepsy
1) females with certain forms of epilepsy are more likely to have seizures during stage of menstrual ccle with highest ratio of estrogen/progesterone
2) [video-Sandy Craddock] violence and menstrual cycle, epilepsy and violence. ~4min]
18. II. Sexual Dimorphisms C. Sexual Orientation (S. LeVay)
1. Interstitial nucleus of the anterior hypothalamus (INAH)
a. INAH-3 2x males vs females
b. INAH-3 ~= gay males vs females
c. INAH-3 2x straight males vs gay males (17.17)
Simon LeVay 1991
19. II. Sexual Dimorphisms C. Sexual Orientation
2. Nature vs nurture (is dimorphism present during development?)
3. Twin studies show < 100% share sexual orientation
4. Few replications
5. Sampling?
Related to Dorner study (stress=?homosexuality)?
20. Think About: Brain
Body