psychoactive steroids Flashcards
what are abilities sexually differentiated in humans during reproductive years
males better: spatial abilities, mathematical reasoning, gross motor skills involving strength
females better: verbal skills, computational accuracy, fine motor skills, short term memory
these differences are only found in large group averages with much overlap in individual scores
when do different steroids peak in males and females
testosterone peaks at around 20 in males and 25 in females
female reproductive hormones peak depending on the menstrual cycle, there is a rapid rise is oestrogen levels during puberty, this decreases during menopause
DHEAS peaks at 20 in females and just after in males, increases during puberty, decreases after peaking, counteracts stress and enhances learning and memory, possible anti ageing supplement? maintains female libido in adult primates
how does testosterone masculine the fetus
5 alpha reductase converts testosterone to 5alpha- dihydrotestosterone which is a potent adrogen receptor agonist and induces the male periphery
aromatase converts testosterone into 17beta-estradiol which is an estrogen receptor agonist, masculinises the male brain and results in sexually dimorphic nuclei
what are some disorders of sexual identity
guevedoces: 5alpha reductase deficiency, results in ambiguous genitalia at birth, becomes truly male at puberty
testicular feminisation or adregen insensitivity syndrome: ineffective androgen receptor results in female appearance
congenital adrenal hyperplasia: excess androgen production in fetal life, can be treated after birth
polycystic ovary syndrome: excess androgen production in adult life
gender dysphoria: a strong and persistent incongruence between gender identity and assigned sex at birth
what are sex differences in brain structure and function between males and females
in utero:
male: testosterone and its aromastisation to estrogen causes masculinisation of brain
female: absence of androgen production and estrogen binding activity of alpha-fetoprotein cause feminisation of fetal brain
adolescence:
male: more between network connectivity, larger grey matter volume, lower grey matter density
female: more within network connectivity, less grey matter volume, higher grey matter density
adulthood:
male: more total brain volume, more grey matter volume, more white matter volume, more CSF volume, higher proportion of white matter, larger volume of central subdivision of the bed nucleus stria terminalis, better visuospatial and mathematical ability, weaker right hand preference
female:
opposite to above; thicker cortex, higher global cerebral blood flow, better perceptual speed and fine manual dexterity, stronger right hand preference
how does the ovarian cycle effect reproductive behaviour
receptive behavioural estrus is found during ovulation (heat)
female rhesus monkey show increased motivation to mate mid cycle
