Hormone effects on brain structure
neuronal survival, connectivity, number or distribution of hormone receptors, neurochemistry
Sex differences in MPOA
Males have more synapses on dendritic shafts and fewer on dendtritic spines, castration on day 1 reverses this. Females normally have opposite pattern. Testosterone treatment given to females before day 4 results in a male like pattern.
Sex differences in SDN-POA
Males have larger (more cells) one than females. Thought to be do to the estrogenic metabolites of testosterone. Testosterone treatment of females and castration of males lead to male and female SDN-POA patterns respectively.
Testicular feminization mutation
rodent equivalent of androgen insensitivity syndrome. males have female external genitalia; normal SDN-POA size.
Sex differences in AVPV
regulates ovulation. volume of nucleus greater in females. males castrated before day 10 have female-like volumes.
Sex differences in SNB
Nucleus in spinal cord of male rates much larger than in females. Motor neurons control muscles attached to the base of the penis that are involved in erection.In females the bublocavernosus and levator ani muscles are atrophied or completely missing.
Androgens in SNB
Androgen treatment rescues muscles in females. If muscle is already die, the androgens can't save it. `
human version of the SNB. Bulbocavernosus muscles present in both males and females. Differences in motor neuron not as pronounced.
Recursive loop in song learning
HVC to area x to dlm to iman to ra. also known as "anterior forebrain pathway" damage to structure can cause song abnormalities.
Sensory-motor Stage Song Learning
Young bird tries to reproduce song from memory. Trial and error learning.
Urinary Posture dogs
postpubertal females treated with testosterone before and after birth showed male urinary posture 50% of the time. Males castrated shortly after birth still shift to male urinary posture at puberty. (Organized by testosterone)
Rough and tumble play rhesus monkeys
males engage in more frequent rough and tumble play than females. Pseuohermaphrodites show frequencies between normal males and females. Castration did not change play frequencies. (organized by androgens)
females have lower threshold and less tolerance compares to males. Females have greater sensitivity to cutaneous and visceral pain; lower sensitivity to muscular pain.
Woman score better than men on odor detection on identification. Woman are 1000x more sensitive to musk like odors.
females show more sensitivity than males. Females show more discrimination between different tastes. Females show estrogen dependent preference for sweet tastes.
men see better than women. women can tolerate higher light intensity and adapt to darkness more quickly than men.
Right ear advantage
sound detection is usually better from the right ear, left hemisphere better at sound processing.
For right handers
right hemisphere used for spatial processing; left hemisphere used for verbal processing
are less lateralized than male brains. Turner syndrome females and those exposed to DES prenatally have male-like lateralization.
women are better a verbal skills including language comprehension, language acquisition, spelling, verbal fluency and grammar skills.
Differences in Verbal Skills
are not organized by hormones. Social and environmental factors cannot be ruled out.
males use left inferior frontal gyrus. Females use both right and left inferior frontal gyri
Male Sexual Behavior
all behavior that are necessary and sufficient to bring male (sperm) and female (ova) gametes together
having sex; involves potency, the capability of having sex and performance, actual mating
forceful expulsion of semen, often accompanied by a sperm plug that blocks intromission by other males.
show decreased motivation and performance, grows more pronounced over time. testosterone can restore sexual behavior but not simultaneously.
experience "natural" castration going into their non-breeding season ex. syrian hamsters in the fall.
reduces male sexual behavior (Aromatase inhibitor). these effects can be overcome with estrogen treatment.
Castration of spinally transected rats
penile reflexes start to decline over 24 hours. gone by 12 days. normal reflexes can be maintained or restored by testosterone implants. DHT maintains or restores penile reflexes.
Estrogen important for
maintaining or restoring sexual behavior via action on the central nervous system.
DHT critical for
maintaining or restoring sexual performance via action on the peripheral nervous system.
lesions of it eliminate sexual performance but no motivation. testosterone treatment does not restore behavior
receives information from accessory olfactory bulb and "olfactory aygdala"; sends information to various hypothalamic nuclei.
after ovulation. corpus luteum develops from ruptured follicle. cornified epithelial cells.
new follicles develop. leukocytes and few nucleated epithelial cells appear. Cornified epithelial cells decrease.
maximal follicular development. behavioral estrus occurs. Increased number of nucleated epithelial cells.
Kiss1 expression in AVPV leading to increased GnRH and LH/FSH release (females only)
extent to which female initiate copulation. equivalent to "appetitive" phase in male sexual behavior. For most mammals, must have high estrogen.
responsiveness to male's sexual advances. equivalent to "consummatory" phase in males. hMust have high estrogen. Requires functional estrogen receptors.
Any behavior that contributes directly to the survival of fertilized eggs or offspring that have left the females body.
When 2 adults are required for survival of young
a parental male will have greater reproductive success than a nonparental male.
extent to which parents compromise their ability to produce additional offspring in order to assist their current offspring.
well developed, ready to cope with environment early on; surivival does not depend much or at all on parental intervention
young are highly altricial, embryo-like. females have pouches that contain mammary glands and are used to carry young.
foster pups are presented to adults to see if and how long it will take to induce parental behavior. invovles different latencies depending on physiological state of primiparous feamales.
oxytocin levels increase
during parturition. injection into brain ovariectomized, estrogen-treated female rats causes expression of maternal behavior in 1 hour.
Anesthetizing mother's muzzle and/or nipples
reduces maternal behavior due to lack of sensory information needed.