Neuroscience of sex Flashcards
girl with CAH: what is it and what are the gonadal and behavioural developments
girls and boys with CAH have higher than typical androgen exposure prenatally
gonadal development: fused labia, masculinized physical development, receive testosterone when the XX framework told them to stop the process so it develops along the masculine pathway
—the clitoris is larger in females with CAH and typically take estrogen as a hormone supplement
behavioural development: lean to more masculine activities and interests, male stereotypes interests (action figures, sports etc.)
—having testosterone on the development of the brain prenatally
what are some concerns with girls with CAH
they are not properly socialized and may have many hospital visits and may have trouble making friends and socializing
—self esteem in sexual activities and romantic relationships
girl with CAIS: what is it and what are the gonadal and behavioural developments
girls with CAIS have XY chromosomes and lower than typical androgen exposure prenatally
—bodies are not able to receive androgens, lack of testosterone prenatally
gonadal development: not going to be masculinized because they don’t have androgens to push the masculine pathways. external and internal genitalia will be female
—usually take estrogen and assigned female at birth
behavioural development: more feminized behaviour and perform like women without CAIS
—more feminine interests and activities, socialization wil have a large impact on behaviours and this has different impacts in different performances
what are the concerns in girls with CAIS
almost always on exogenous estradiol (not actually studying the brain and body clear of activational effects of hormone exposure
organizational effects vs activational effects
organizational: prenatal hormones effect, PERMANENT structuring, and mini-puberty
—organization of the brain happens prenatally and it is permanent structuring and it is fixed
activational: pubertal and post-pubertal hormonal effects, transient function in adults
—affects happen later on in life and happen with the secretion of testosterone and estrogen prenatally
what are some tools for studying organizational effects
anthropometric measures (comparisons of different aspects of the body - (height and weight, digit measures) proxy of testosterone exposure prenatally
—measured fourth and second digit and based on ratio can tel you how much testosterone who you during development (women have a longer 4th digit and men tend to have smaller)
sex-typed interests: toys and people you play with etc.
cognitive performance: verbal fluency l, math performance, visuospatial cognition
hormonal inversion in homosexuality, what it is and did it work?
Eugen Steinach performed testicular transplants on homosexual men to try and convert them back to heterosexuality. this did not work
he did this by removing one teste and replaced it with a testicle from a straight men as well as did hormonal injections but no difference was note
homosexuality was thought to be the fault of the tested developing estrogen instead of testosterone making these men appear more feminine with feminine interests
describe phoenix et al guinea pig study. what were they studying?
they manipulated the utero environment of pregnant guinea pigs and observed their sexual behaviour as adults
they did this by castrating the gonads and injecting the guinea pigs with hormones to observe their sexual behaviours
—injected with hormones while female was pregnant to manipulate the prenatal environment
phoenix et al methods (3)
testosterone propionate injections to pregnant pigs and tested the sexual behaviour of the male and female young (mounting vs. lordosis)
prenatal environment high in testosterone
gonadectomized young and then injected then with sex steroid hormones and observed behaviour
why did they castrate the young after the mother was injected with testosterone? what experimental check does this provide?
in order to rest the effect of the prenatal environment the castration is required and if they didn’t castrate the animals they would not be able to distinguish between the adult hormones and the effects of prenatal manipulations
—completely removing the gonads allowed researchers to completely test the effects of the prenatal environment
what we’re the phoenix findings? (2)
external genitalia of female pigs was masculinized (dose-dependent) and female typical behaviour was not recovered by estrogen or progesterone injections in adulthood
no abnormalities were reported in genitalia or behaviours in males
examples of organizational effects (think phenotype)
masculinization and defeminization of the phenotype or feminization or demasculinzaion
the four-core genotype model
this model describes activational effects as “reversible”
—gonadectomy in adults remove sex differences caused by activational effects
some sex differences are not caused by sex hormones
arnold and chen four genotype model
they have females the SRY gene and made them XX-SRY individuals
they were able to study phenotypic sex (presence or absence of testes) and sex chromosomes
—mice had different chromosomes but both had testes and they have different behavioural responses
what did arnold and chen find? (3)
FGC mouse demonstrated sex differences that were NOT mediated by gonadal hormones:
- gene expression
- susceptible to diseases
- behaviour: aggression, parenting, habit formation, nociception, social interaction
