Lecture 9 - Reading Flashcards
Stress hormone affects on fetus
Hypothesis by Nathanielsz
Stress hormones impacting a fetus can directly alter stress responses later in life
Hypothesis by Nathanielsz: set-points in the HPA axis would have been altered by neonatal stress hormone elevation altering the animal’s stress responses even throughout adulthood
Early exposure to glucocorticoids contributes to temperament and affects likelihood of depression and other mood disorders
What happens of you inject test into a newborne female mammal?
2 things
One menstrual and one behavioural
Won’t ovulate
Won’t display female-typical sexual behaviors
If newborn male is deprived of testosterone (castration)
2 things
Increase LH levels following estrogen and progesterone exposure
Will display female-typical sexual behaviors
If testosterobe is injected into a female in the critical period for sexual development (3 things)
Hypothalamus
LH secretion pattern
What type of sex-specific sexual behaviours
Low number of hypothalamic preoptic area spine synapses
Acyclic LH secretion
Low female-typical and high male-typical sexual behaviors
Effects of early sex hormones If test is injected into a female after the critical period (1 thing)
No effect
Critical period in humans vs. rats
Critical period for humans occurs in utero, but for rats it occurs after birth
What happens when you have elevated stress hormones prenatally
HPA axis is sensitive to high maternal glucocorticoid levels
Elevated adrenal hormone levels in the prenatal period → greater stress sensitivity in sympathetic NS, altered learning capacities
Prenatal stress hormone may increase neuronal vulnerability to oxidative stress
Basics of CAH
Congenital adrenal hyperplasia (CAH): genetically based deficiencies in enzymes involved in glucocorticoid synthesis leads to a decrease of steroid precursors into androgenic pathways
Excess in utero testosterone can cause pseudohermaphroditism, abnormal external genitalia development
Androgen insensitivity basics
Androgen insensitivity: have external female genitalia, have testes that secrete testosterone, are sterile
Females (vs. males) are usually (6 things)
1) More interested in parenting
2) Better overall verbal ability
3) Speech production
4) Verbal fluency
5) Math problem solving ability better in childhood
6) Better perceptual speed and accuracy
Males vs. females are usually (6 things)
1) More likely to be left-handed
2) More aggressive
3) More likely to have language left-lateralized in the brain
4) Better at analogies
5) Problem solving ability better in adulthood
6) Better and faster at mental rotation
XY individuals with complete androgen insensitivity have
female phenotypic sex, sex of rearing, and gender identity
So concurence between phenotypic sex and gender
Not definitely genotypic
XX individuals with CAH have
What genitals at birth
Will this be treated?
Often have what sex-typical behaviours
masculinized external genitalia at birth
but it’s usually treated surgically
tend to have more male-typical behaviors
How does stress hormones early in development change things?
What brain regions are altered (2)
How do neurons here tell the rest of the brain what to do?
High levels of stress hormones during early development may cause alterations in the:
lower brainstem
locus ceruleus
Neurons in this region respond strongly to salient stimuli (including stress) and tell the rest of the brain about them through long-ranging adrenergic projections
Prenatal stress hormone injection in rats caused… (4 things)
1) Reduced ACTH production in the periventricular nucleus of hypothalamus
2) Reduced expression of CRF/CRH, the neuropeptide that causes ACTH release
3) Reduced expression of glucocorticoid receptors
4) Reduced vasopressin production
