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Nervous System: Unit IV > Gender & the Nervous System > Flashcards

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Incidence of aphasia in women vs. men

  • female language representation (~Broca's area) >> male language representation (Broca's area)
    • + language is represented somewhat more bilaterally in women
  • smaller stroke ==> aphasia in men
  • small stroke in women most likely spares some portion of Broca


Effects of prenatal & perinatal exposure to sex steriods

  • Prenatal: Sex steroids have organizational effects
    • determine the fate of cells in an irreversible way when developing.
  • Perinatal: changes short term physiological functions
    • “activational”


Sex steroids impact on brain activity/structure in adults

  • Classic steroid receptors - change transcription over days to months.
  • Unknown GPCR on neurons and glia
  • Direct interaction with GABAA  receptors


Cerebral cortex targets of androgens

  • areas involved in sexual fxns
    • hypothalamus
    • preoptic area
    • amygdala
  • cerebral cortex
    • steroids can be used as anxiolytics or anesthetics
    • interaction (estradiol) w/GABA receptors ==> lower seizure threshold (e.g. during menses) 


Steroid impact on development

  • sex-associated brain differences = secondary sexual traits
    • depend on teststerone and Mullerian duct inhibitory hormone
    • exposure must occur during critical period for permanent effects
  • female brain state = default; male brain development depends on testosterone


Organizational effects vs. Activating effects of sex hormones

  • organization = permanent alterations that occur during developmental critical period
  • activational = temporary, reverrsible changes (e.g. anxiolysis or cognitive abilities)


Testosterone role in early development

  • Creates subtle differences in male brain 
  • Androgen insensitivity disorder 
    • lack of fxn androgen receptors
    • XY genotypes have "female-type psychosexual orientation" (whatever that means) w/normal testes and testosterone levels


Sexual dimorphism in human brains

  • Preoptic area & anterior hypothalamus
    • in females: neurons @ preoptic area release LHRH ==> LH and FSH release
      • LHRH neurons are linked by gap jxns (but not in males) ==> synchronized discharge
  • sex steroid receptors (esp. estrogen) located throughout brain
  • corpus callosum, lateral fissurem amygdala


Steriod effects on adult nervous system

  • main source of steroids at brain = brain itself (not gonads)
  • have fast MOAs @ brain:
    • Membrane-associated and cytoplasmic classical steroid receptors that use second messengers (instead of DNA-binding) 
    • cell surface steroid receptors acting via second messengers
    • direct allosteric interaction between steroids and GABAA receptors
      • ==> use as anxiolytic or anesthetics