Week 8 mixture Flashcards
________________ a regularly recurrent state of sexual
receptivity during which the female of most
mammals will accept the male and is capable of
conceiving
Estrus:
Examples of estrus
○ Female hamsters only nice to males during estrus
○ Female baboons have sexual swellings to indicate fertility
● Human females do not have any obvious signals
of
estrus to indicate fertility
○ Humans also have _____________: engage in sexual behavior throughout hormonal cycle
extended sexuality
Desires during fertility should be inputs__________
○ This is a straightforward prediction from sexual
selection theory
○ Occurs in animals: females will mate with the
__________male when they are fertile
to mating adaptations
“optimal”
What is the controversy of selection theory when applied to humans
Controversy when applied to humans
○ Humans all look different
○ Humans might not have estrus (obvious physical
signals)
○ Effects on this idea do not always have reliable
measurements
■ Different experiments use different methods
______________ When fertile, women elevate their preferences
for putative indicators of good genes
ovulatory shift hypothesis
● Shows that humans are not emancipated from
all hormonal control
Women place a higher priority on specific male
characteristics
○ To pass on good genes to their offspring
Scent of symmetry study
○ Women at high fertility preferred body odor of more
symmetric males
○ Women at low fertility did not show much preference
Women’s attraction to their own
partners and other men ___________
changes
throughout their cycle
○ Woman was more interested in other men
during high fertility if
their male partners was
less sexually attractive
What are some cue of ovulation
Behavioral: clothing choice, flirtation, body
movement
● Vocal: pitch, attractiveness
● Olfactory: body odors
Men are picking up on some type of
__________
fertility/ovulatory cue
○ Challenge hypothesis: in the presence of fertile female, if rivals are present,
then T goes up to potentially fight or
mate
○ Male’s testosterone increased in response to competition
during partner’s high fertility
women’s hormonal state can have an impact on
her partner’s hormonal state
Women’s sexual interests change across their cycle
Women place a premium on male attractiveness while they are fertile
○ Robust upward shift in women’s preference for all purported cues of
genetic quality
● New studies are examining if other relationship factors
mute or amplify cycle
shifts
○ EX: bondedness with partner
___________ congenital conditions involving atypical
development of chromosomal, gonadal, or
anatomical sex
DSD: disorders of sexual development
● Complete Androgen Insensitivity Syndrome
(CAIS)
XY males with mutation in androgen receptor causing
insensitivity
○ Female external appearance, and female-typical gender
identity
○ Internal testes, no ovaries or uterus
Abnormal number of sex chromosomes →
Turner Syndrome (XO); Kleinfelter Syndrome (XXY)
Excess androgens (XX genotype) → ___________
Congenital Adrenal
Hyperplasia (CAH)
___________ the personal sense of one’s own gender
○ Unique to humans
Gender Identity:
_____________ persistent cross-gender
identification and discomfort with the natal sex
Gender dysphoria/incongruence (GD):
Embryo begins as __________
biopotential
Sex differentiation occurs due to genes
○
Sry (XY) → testis
○ No sry (XX) → ovaries
Males: have what organization and activational effects of testosterone.
organizational period of masculinization
in brain due to T → E2 during fetal development
○ Activated in adulthood by high T
● Females: ___________
during organizational period (probably)
○ Activated in_____________
no active hormonal contribution
adulthood by high E2 + progesterone
● Testosterone is converted to estrogens by __________ in many areas of the body
aromatase
Role of E2 in female neural development: ArKO♀. The goal of the experiment was to
examine if there are feminizing effects of E2 on brain development
○ Currently, organization of feminine brain is thought to have _____________
no hormonal influence (lack of T)
● ArKO♀ showed reduced __________
○ Compared to wt and heterozygous KO
lordosis behavior
● Female aromatase knockout mice (ArKO♀)
○ Targets aromatase gene
○ Global knockout → no aromatase in any tissues → cannot synthesize estrogen anywhere
○ Estrogen receptors are unaffected; possible to supplement E2
ArKo not exhibiting lordosis showed ○ Demonstrates there is
no E2 production to influence activational effect (lordosis) in brain
Role of E2 in female neural development Estrogen given early post natal showed: WT control showed \_\_\_\_\_\_\_\_ ArKO♀ \_\_\_\_\_\_\_\_\_\_\_ ● WT and ArKO♀ given EB \_\_\_\_\_\_\_\_\_\_\_\_
lordosis (expected)
did not show lordosis (expected)
did not show lordosis
Role of E2 in female neural development Estrogen given prepubertal: WT control and WT with EB showed \_\_\_\_\_\_\_\_\_\_\_\_\_ ArKO♀ \_\_\_\_\_\_\_\_\_\_\_\_\_ ● ArKO♀ given EB showed \_\_\_\_\_\_\_\_\_
lordosis (expected)
did not show lordosis (expected)
lordosis
Role of E2 in female neural development.
Based on the prepubertal estrogen experiment
○ EB restored lordosis behavior → activational
effect
Based on the post natal development experiment,
EB likely
masculinized the brain when given during when mice were sensitive to organizational
effect
Kisspeptin neurons are a
○ Female AVPV has more kisspeptin neurons than males
○ Organized by E2 during prepubertal period
sexually dimorphic area of the brain
■ Increase kisspeptin neuron population in_________ as E2 increases with development
AVPV
○ Important regulator of GnRH → __________
involved in HPG axis
● Kisspeptin is involved in __________
○ Activational effect of kisspeptin on a feminine behavior
○ Exact pathway/projections not understood (yet)
lordosis behavior
Female________ has more kisspeptin neurons than males
AVPV
CAIS comparison to robust sex differences in brain
showed the sexually dimorphic areas of the brain
Mental rotation task: sexual difference in brain
activation
○ Men use parietal areas
○ Females use frontal and temporal areas
● MRI: compare 2 images so the highlighted
areas are
the differences between them
○ A: Control men are more active ___________
(in the parietal
area) than control women
○ B: Control men _______ than CAIS
are more active
_________have similar
activation
○ C: Control women and CAIS
● Female-typical neural activation in _________
CAIS
subjects
○ Females show less activation of____________
left inferior
parietal lobe than men
__________measure directionality of
brain matter structure
FA = fractional anisotropy =
○ Men typically have higher
FA than women
● Similar image comparison to MRIs
○ Men show higher FA than women
○ Men show higher FA than CAIS
____________
○ Women and CAIS have similar FA
Conclusion from CAIS studies:
● CAIS subjects show
female-typical neural
characteristics
● Suggests that _________
play a predominant role for brain sexual
differentiation
androgens, not sex chromosomes,
Female-typical brain microstructure shown in CAIS
subjects
White matter microstructure
Men > Women
Men > CAIS
Women ~ CAIS
CAIS comparison to robust sex differences in brain
CAIS=Complete Androgen Insensitivity Syndrome: XY males with insensitive androgen receptor
Hypothalamus’ response _________ is an
objective measure of brain function
○
androstadienone
Androstadienone: odorous steroid found in blood, sweat,
semen; mostly secreted by ________ smelling it causes a reaction in __________
males Smelling it causes hypothalamic activation in females
■
See response in prepubertal children and adolscents → hard wired _____________
sex diff established before puberty
● Sex reversal in adolecent GD: responded ____________
○ Control girls responded, girls with GD did not
○ Control boys did not respond, boys with GD did
like their
desired sex
Additional studies’ results:
● Transgender boys and girls showed ____________
intermediate gray matter
volume in male/female dominant sexually dimorphic
structures
● Transgender women showed ___________
neuropeptide expression (neurokinin-b and kisspeptin) similar to female-typical levels
Individuals with GD possess certain functional brain characteristics typical
of their experienced gender
CAIS subjects demonstrated female-typical characteristics → _________________ play a predominant role in brain sexual differentiation
androgens, rather than
chromosomes,
Mental rotation task:______________
female-typical fMRI
White matter
microstructure: female-typical FA values
Why would a female’s desires be sensitive during their fertility?
○ To pass on the best genes to their offspring. EX: female golden collared manakins want a male who
has the fastest roll snap, because it likely shows improved fitness.
● If humans were emancipated from hormonal control, what type of results would we
see in the scent of symmetry study?
○ Female response to a male’s scent would have no correlation with their facial symmetry; they would
have no preference throughout their entire cycle
● In these studies, why are only naturally cycling females participants?
○ Hormone therapies (like the pill) “flatten” out the hormone cycle so there is no more cycle. They do not
have a high fertility phase, and they may not ovulate. These studies would not be able to compare a
high vs low fertility phase. Different types of contraceptives have different effects.
● Do female humans have estrus?
○ It seems like female humans (who have natural ovulatory cycles) have extremely subtle estrus cues.
Research is still ongoing!
Do ovaries use aromatase?
○ Yes. To make estrogens anywhere you need testosterone to be converted into estrogen by
aromatase
● What is a possible conclusion based on the [mouse ArKO study] results?
○ There is a possibility of different critical windows for male/female development.
○ E2 masculinizes the brain during development (during organizational window)
○ Organization for males occurs prenatally, organizational for females occurs postnatally
(according to this data)
