Unit 2 Hormones and Behavior

levels of sex determination

-chromosomal sex
-gonadal sex
-hormonal sex
-morphological sex
-behavioral

species vary on there

sex differences, Ex prairie volves male and females do not have much differences but elk do as males compete for females

SRY

sex determining region on Y chromosome

TDF

testis determination factor

germinal ridge

bidirectional tissue will automatically develops to ovary unless SRY is present

embryonic ovaries are

quiescent (inactive dormant)

female pathway of development is

presence of ovaries or absence of any gonads

Mullerian inhibitory hormone

mullerian is a duct in the female tract the inhibitory hormone that dissolves this duct and triggers male pathway of preserving wolffian pathway and mean the testies is activated

Differentiation V determination

differentiation done by hormones and determination is SRY gene>>>

In females Wolffian

automatically dissolves
Ovaries are not active

What do males need

defeminization and masculation
-androgens fro wolffian duct development
-MIH for regression

DHT (5-alpha-dihydrotestosterone)

more potent than testosterone, not in females they have 5 alpha reductase, an enzyme that converts testosterone to ...

turner syndrome

XO under developed girl, hormonal treatment in med-teen to induce puberty

Exposure to androgens

Exogenous- environment or steroid treatment
endogenous- ovaries or adrenal gland
ex: congenital adrenal hyperplasia: fetal adrenal glands produce androgens masculinizing genitalia in females

Testicular Feminization mutation (TFM)

(androgen insensitivity syndrome): lack of functional androgen receptors- female external genitalia , sexed and reared as girls

5 alpha reductase deficiency

genetics males more with ambiguous genitala small undescended testes, sexed and reared as girls until puberty when androgens masculinize body

trisomic anomalies

XXY (klinefelter syndrome) born as male, Y sufficient for masculinization- sterile due to reduced sperm production, learning disabilities
XYY born as male, sterile, agression

hormone effect on sexually dimorphic behavior

inject pregnant mice with testosterone increased mounting behavior

decrease in estrogen

decrease in lordosis: female behavior

Hormonal events early in development are responsible for induction of masculine and feminine behaviors and for shifting of probabilities of masculine and feminine mating behaviors in males and females.

look at slide 14

Young's speculation

-distinction between organization and activation
-critical period during perinatal development
-organization of the neural tissue mediating mating behavior in analogous to the differentiation of the genital tracts

the organization/ activation hypothesis

exposure to sex steroid hormones in early development perm organizes/ establish the neural substrate that will be needed for male/female behaviors and that the same hormones activate, modulate, or inhibit behavioral functions in adulthood by acting upon these organized structures

freemartinism

Freemartin: a sterile, female twin of a male found in cattle, sheep, goats, and pigs.

the study of freemartinism

A female calf (XX) born as a twin to a normal male • 90% of females having male twins are freemartins • The external genitalia is of the female type • The gonads resemble testes more than ovaries

hormonal hypothesis

androgens or other masculinizing factors are able to reach to the female through vascular connections of the placenta and affect the internal anatomy of the female

intrauterine position affects physiological and behavioral function of female rodents

What does the 2 M mean in the powerpoint. slide 21??????????

HPA and HPG

work on a negative feedback regulation as estrogen and will inhibit the hypothalamus

HPA axis

the hypothalamus, pituitary gland, and adrenal cortex

HPG

hypothalamus, pituitary, gonads

hormonal control of ovulation

females have an LH surge, males do not

Femal gonads are

cyclic

male gonad release is

tonic (reproductive beh follow similar pattern)

estrogen regulation

works on a concentration gradient so low concentration inhibits the pulse center but at high concentrations will be positive reinforcement

pulse center

in hypothalamus, controls pulsating release affected by GnRH

androgen to estrogen is done by

aromatization

alpha fetoprotein

protein that binds with estradiol in the bloodstream of immature mammals ??????

plainfin midshipman fish example

two different types of males. One imitates a female and is sneaky and the other develops to be big and manly

example of sex beh in dog

male dog pee with one leg up while females do not

the medial preoptic area

a region of the hypothalamus involved in the regulation of sexual behaviors typically shown by males

males have more synapses on

dendritic shafts

females have more synapses on

dendritic spines

If neonatal castration occurs what happens to synapses

female pattern of synapses

what happens when testosterone injection before postnatal day 4 in females

male pattern of synapse occured

sexual dimorphism

Differences in physical characteristics between males and females of the same species.

Sexual dimorphism can be seen in the

CNS

neonatal hormonal manipulation alters

neural structures

Gorski study

More neurons in males at testosterone increases neurogenesis and decrease cell death function unknown.

which sex has more neurons during gestation

males are born with more neurons

How does Testosterone affect cells

enhances neurogenesis and reduces cell death. Testosterone is aromatized to E in order to masculinize SDN

where is the interstitial nuclei of the anterior hypothalamus (INAH) 2 and 3 greater

are greater in men than in women

LeVay reported that

homosexual men have smaller INAH3 than heterosexual men

the bulbocavernosus muscle

Contracts to stop the flow of urine, and helps with erection and the expulsion of semen.

? what does this have to do with the class slide 10)

The spinal nucleus of the bulbocavernosus (SNB) is

-smaller in women than men, absent in mice
-the SNB cells and muscle die in 1st week in female rats
-the SNB system can be permanently saved in females with a single injection of androgen but once it dies androgen can not reverse it

sexual brain dimorphism

? what is slide 13 on about

song learning in 2 stages

sensory and sensory-motor stage

sensory stage

hear and memorize the song

the sensory motor stage

reproduce the song stored in memory learned by trial and error after the 2nd stage the full adult song is crystallized damages to the recursive loop especially the area X and IMAN before the song is crystalized result in abnormal song

zebra finches sexually dimorphic nuclei

HCV and RZ are 3 to 6 larger in males. X area can not be discerned in females, neurons are larger more numerous and further apart in males

castration in male zebra finches

castration leads to a reduction in singing but not the size of the brain nuclei controlling song production

T treatment in adult females zebra finches

does not induce changes in either singing or the size of the song control regions

activation effects of steroids alone

do not account for sex difference in the brain nucleus size or in singing behavior in zebra finches

diagram on slide 20

and 21

sexual behavior

bring the two gametes together

appetite phase

searching or providing food fighting for territory or advertising

consummatory phase

copulating, mounting, intromission and ejaculation

how does castration affect beh

reduced sexual beh

sex drive is expressed

overtly after puberty

how does androgen affect mating beh

affects the likelihood of mating behavior by reducing the threshold in the presence of the appropriate neural substance and social stimuli

maintenance and restoration

in order to maintain sexual beh less testosterone injections is needed compared to restoring sexual beh. this is because circulating androgen is required to keep receptors

what is needed for mating beh

testosterone, castration showed decrease in beh and post castration testosterone treatment showed increase in beh

testosterone is converted into

estrogen.
Estrogen is almost as effective as Testosterone. Both hormones can be blocked by ER blockers (means that testosterone has no effect when estrogen receptors are blocked)

What is needed to restore mating to levels of intact males

estrogen plus DHT. T acts as a phroprome providing E to the CNS to promote beh as well as DHT to periphery to maintain tactile sensory feedback

sex drive

motivational force that propels individuals to seek the sexual union

the obstruction test

a way to test sex drive through testing mount latency. Using a physical barrier to test sexual motivation

lESION study

removal of a critical component of the neural substrate underlying sexual behavior can be done electrical and chemically

vomeronasal organ (VNO)

a collection of specialized receptor cells, near to but separate from the olfactory epithelium, that detect pheromones and send electrical signals to the accessory olfactory bulb in the brain

ways to impair olfactory

-bulbectomy surgical removal
-intranasal infusion of zinc sulfate
-anesthesia of the nasal epithelia

bulbectomy

neural damage and is irreversible

intranasal infusion of zinic

temporarily destroys the nasal neuroepithelia

anesthesia of nasal epithelia

temp olfactory impairment

olfactory impairment shows

male rats rail to achieve ejaculation or even do not imitate copulation. the bulbectomy eliminated sexual beh in males

Preoptic area

A region in the anterior hypothalamus involved in generating and regulating male sexual behavior.

dopamine in POA

monoamine
lesions of this cause loss of sexual performance. DA agonist restore mating beh. Overall dopamine has a role in POA for male sexual beh

castration reduces what in mPOA

neural responsiveness

Testosterone in mPOA

mediate male mating seen through castration no effect T & E implant facilitated the mating. cholesterol had no effect

How does T in mPOA mediate mating beh

T in the mPOA mediates mating via aromatization to E. T implant when injected with ER blocker did not induce mating showed that T conversion to E is necessary for mating beh

coolidge effect

male exhibit renewed sexual interest whenever a new female is introduced shows that presence of a novel female is needed (same female increase time in order to ejaculate)

vaginal code

tested through a room where only female can enter. showed that female will socialize with each other and female will go over when want sexual encounter termed female pacing

social stimuli affect

male mating beh.
• Previous experience and conditioned stimuli - conditioned stimuli will also cause endocrine changes

difference between paced and non paced

when females are in an environment when they can pace the mating the rates of pregnancy are much more successful

hormonal hypothesis for beh

individual difference in level of hormonal circulating can account for individual differences within species. Was rejected due to slide 27

among species

genotype is important doe differences in mating behavior

effects of castration

varies among individuals

Females sex bev

precopulatory-to attract a male to initiate copulation

copulatory- response to sexual initiation of a male

Vaginal cytological Assay

done by stockard and papanicolaou changes in vaginal cell types are closely related with changes in ovarian functions in guinea pgs

behavioral estrus coincides with

the vaginal proestrus `

follicular phase

follicles produce E

egg development

10-14 day in human and 3 for rodent

periovulatory period

egg matures E increases along with GnRH LH FSH

surge produces P release from ovary

12 hours for rodents

1-2 human

luteal phase

follicles to corpora lutea

identical to pseudopregnancy

corpora lutea produces

progesterone for implantation and pregnancy maintenance