Exam 3 prep Flashcards
Understand different hormonal and neural mechanisms of control of parental behavior
Explain the time course of release of sex hormones, oxyotcin and prolactin during pregnancy and lactation
Prolactin:
- we see prolactin low in the beginning of pregnancy
- later in pregnancy we see a high level especially during lactation
Oxytocin:
- plasma levels raise at the end of pregnancy and remain elevated through lactation
- oxytocin receptors are activated in late pregnancy by estradiol and progesterone
- oxytocin facilitates maternal behavior in females
Explain the mechanism of production of estriol during pregnancy and it’s importance as a test hormone during pregnancy
Estriol:
- Made by placenta from DHEAS (a weak androgen) that is produced in the adrenal cortex of the fetus
- Placenta also produces progesterone from maternal cholesterol
- Estriol is present in maternal blood circulation and urine, and binds to estrogen receptors
- Estradiol is the marker of fetal health in the second trimester
- Low estriol level in second trimester predicts preterm births
- may indicate congenial anomalies in fetus
Explain the relationship between reproductive strategies and parental behavior
- Monogamous relationships showed elevated parental investment
- Polygynous relationships showed lowered parental investments
- Polyandrous relationships showed lowered parental investment
Reproductive strategies
- Altricial: helpless, unable to move
- Semi-precocial: not quite helpless, capable of grabbing
- Precocial: ready to move and follow (imprinting is important)
Explain the relationship between maternal behavior and stress responsiveness
Discuss the various hormones associate with the control of maternal behavior
Oxytocin
Oxytocin:
- Estradiol and progesterone enhance oxytocin production and oxytocin receptors in the brain
- Oxytocin facilitates maternal behavior in females
- Dams performing better maternal behavior have enhanced oxytocin release and receptors in the medial preoptic area
- Produced by the brain and have receptors present in the brain
- Oxytocin is estrogen and progestin dependent
Discuss the various hormones associated with the control of maternal behavior
Prolactin
Blockade of prolactin receptor production by antisense mRNA:
- inhibits maternal behavior
- increases anxiety
- increase ACTH production and release
- modulates oxytocin release under basal and exercise conditions
Discuss the various hormones associated with the control of maternal behavior
Estradiol and progesterone
- Blockade of estrogen receptors by tamoxifen implants within the POA inhibits maternal behavior
- vaginal stimulation of maternal behavior in ewe works best in estrogen treated or progesterone-primed animals
- During pregnancy: estradiol levels are low and progesterone levels are high
- Estradiol level increases late in pregnancy, while progesterone levels drop
- Pregnancy: low estradiol and high progesterone leads to activation of estrogen receptor alpha
- Sequential treatment with progesterone and estradiol facilitates maternal responsiveness in virgin female rats
- Effect works best after removal of progesterone
Discuss differences in paternal behavior and affiliation between closely related species of voles, mice, and hamsters. Discuss difference in affiliation within a species. What mechanisms could cause these differences
Prairie/ Pine Vole:
- Monogamous bonds
- Some “cheating”
- shared territory
- Mate guarding
- Paternal behavior
Montane: Meadow Vole
- Polygynous
- Solitary
- Opportunistic mating
- No mate guarding
- No paternal behavior
Voles: their behavioral differences are related to differences in receptor expression
- Neural systems associated with affiliation:
-Dopamine reward circuitry - Vasopressin interacting with reward circuitry
- Oxytocin interacting with reward circuitry
Explain gender differences in the neural control of affiliation
Vasopressin and oxytocin: cause sex differences in affiliation
- in males: vasopressin facilitates affiliation with female partner
- In females: oxytocin facilitates affiliation with male partner
Explain relationship between vasopressin and testosterone in the control of affiliation and paternal behavior
Vasopressin and Steroid Hormones
- Large AVP neurons have estrogen receptor beta
- Small AVP neurons in amygdala have androgen receptors and estrogen receptor alpha
- Small AVP neurons in amygdala and their projections are sexually dimorphic and testosterone-dependent
- Vasopressin enhances dopamine release
- Vasopressin in nucleus accumbens are critical to affiliation
Explain relationship between affiliation, parental behavior and addiction. Describe common neural mechanisms and substrates
- Vasopressin and oxytocin in nucleus accumbens are critical to affiliation
- Individual differences in affiliation in males are associated with individual differences in vasopressin receptor expression within addiction circuitry
- Vasopressin near accumbens modulates dopamine release and activates addiction circuitry
- Separation of pairs causes “depression” like behaviors in voles
- What if a species does not have these small vasopressin neurons
Explain different forms of testing for parental behavior, affiliation, and aggression
Explain different types of aggression and related definitions.
How do definitions of aggression in animals relate to humans?
Explain relationship between testosterone, corticosterone, aggression, and dominance
- offensive aggression is testosterone-dependent some of the time (reproductive season)
- defensive aggression is unrelated to testosterone
- winning enhances plasma testosterone levels, losing decreases them.
- in winter, high offensive aggression seems unrelated to testosterone, but related to HPAA axis
- anabolic steroids enhance:
offensive aggression in animals, reactive aggression in humans, and risk taking in animals and humans
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