(E1, L5) Sex Differences Flashcards
Why are there sex differences in the toys that children and monkeys choose to play with?
- social influences (parents, peers, culture, etc.)
- biological differences (monkeys chose the toys most associated with their sex when given a choice between toys they’d never seen before)
Describe the development of sex differences in toy choices.
- Human sex differences in toy preferences emerge by 12 or 24 months and seem fixed by 36 months
- Some data show that preferences are present before then due to eye tracking experiments
- Color preferences don’t show up until 2 yrs old, so nurture may play a larger role
- girls with CAH play with masculine toys more often than girls without CAH, with a dose-dependent effect
Why study sex differences?
- differences between gender and sex
- medicines and therapeutics–>each cell has a different sex
- sex differences in brain and peripheral nervous system
- important political, medical, and ecological implications
– drug doses different between sexes
– homosexuality had been seen as a mental health disorder
–species of fish that start off as female and become male
What hormone receptors are influenced by sex differences?
- estrogen receptors (both alpha and beta0
- progesterone receptors
- androgen receptors
- corticosteroid receptors
- dopamine neurons (NTs)
- kisspeptin neurons (NTs)
Cell numbers might be the same in brain regions between genders, but what is happening within those cells is different
What are sex differences in bullfrog brain mediate calling behavior?
Female bullfrog: less cells in POA contain AVT receptors
Male bullfrog: More cells in POA contain AVT receptors
Describe the sex differences in zebra finches
- Sexually dimorphic brains
- songbirds (males, not females) produce complex vocalizations that are learned during development
- male zebra finches sing to attract females and ward off competing males
- Females never sing, even after being treated with T in adulthood
What are the differences between Zebra Finches, Canaries, and Bay Wrens?
female zebra finches never sing: dimorphic brains
female canaries sometime sing: brains are different but similar
female bay wrens sing equal to males: brains are similar to males
What are the neural bases of sex differences in birdsong?
- the volumes of several brain regions in songbirds display substantial sex differences
- two major brain circuits for song show differences
— efferent motor pathway
— auditory transmission (or anterior forebrain) pathway - the sex differences in theses brain regions parallel sex differences in singing behavior
Describe the development of birdsong
- The song learning process occurs in two stages
1. during the sensory stage, a young bird hears and memorizes the song(s) of adult birds
2. this is followed by the sensory-motor stage, where the bird tries to sing the song that is stored in his memory - crystallized songs –> recognizable as an altered version of father’s song
(deaf birbs can still produce a song, but it is not crystallized after a father’s song)
What are the sex differences in brain regions relating to birdsong production?
- HVC and RA of male zebra finches are 3-6 times larger than in females, and Area X cannot even be discerned in females
- the larger size of these regions is due to the larger, more numerous and scattered neurons in these nuclei
- Castrating adult male zebra finches reduces singing, but doesn’t change the size of the regions
- androgen treatment of adult female finches does not change singing or size of brain regions
What are the types of sex differences (in humans)?
Qualitative differences (M behavior vs. F behavior)
Quantitative differences (FB overlaps MB)
Population differences (MB distribution vs. FB distribution)
Underlying Mechanisms Differ (Male Neural mechanisms vs. female neural mechanisms and their resulting behaviors)
What are the sex differences in relation to pain?
- females generally have a lower threshold for pain and experience pain with greater intensity and frequency
- natural variations in hormones effect pain, with estradiol enhancing pain detection (changes throughout menstrual cycle)
- the opioid system activates in response to pain, but does so to a lesser extent in women
- women are more frequently diagnosed with chronic pain
(There are also social differences in the reporting of pain. i.e. males are more likely to report it to a male experimenter than a female experimenter)
What are the sex differences in relation to olfaction?
- women are approximately 1000 times more sensitive to musk-like odors than men
-These differences appear at puberty and are estrogen-dependent - Women also exhibit increase brain activation in some regions than do men, per fMRI analysis during sniff tests
- additionally, periovulatory women and women who are in early pregnancy demonstrate enhanced sensitivity to smell
What are the sex differences in taste?
- women display more sensitivity than men and have better discrimination of tastes
- There are also sex differences in taste preferences in lab animals (females prefer sweet tastes like sugar)
What are the sex differences in audition?
- Women are more sensitive than men to sound, hearing pure tones at lower thresholds than men (which is especially true at high frequencies) and occurs at all ages
- women have louder otoacoustic emissions than men, a sex difference that is present from birth (faint echo-like emissions from cochlear are louder)
– Women with CAH tend to have more masculine emissions: “quiet ears”
