Flashcards in 22 Neurobiology of sex, attachment and empathy Deck (37)
How widespread is sexual dimorphism?
Most animals and plants - masculine and feminine form
What are the two main periods when sex hormones have developmental function?
Around period of birth and during adolescence
What are the main sexually dimorphic hormones for early stages of development?
Testosterone, oestrogen and progesterone
What part of brain is most involved in modulating release of sex hormones?
How does the hypothalamus influence activity influence activity of testes and ovaries?
Gonadotropin-releasing hormone (GnRH) is released from the hypothalamus to...
Anterior pituitary, which produces gonadotrophins - follicle-stimulating hormone and lutenising hormone – which...
In male testes - produce sperm and testosterone
In females - produce oestrogen and progesterone
What is in the medial preoptic area?
It contains the sexually dimorphic nucleus
Does castration reduce sex drive?
Only if it's done before puberty. In adult men, it appears testosterone does not regulate sex drive - more a habitual drive
How does relative length of ring and index finger in men indicate testosterone levels?
Longer ring finger is relative to index, more testosterone around time of birth. These men more risk-taking (eg. in financial industry) and more likely to be international footballers/coaches.
What is the effect of lesioning the medial preoptic area in male rats?
It abolishes sexual behaviour
What else reduces size of medial preoptic area?
Stress levels of parents
Which hormone appears to be most important in controlling women's sexual behaviour?
Which hormone appears around the time of ovulation?
Luteinising hormone - it stimulates ovulation
(and a little bit of follicle-stimulating hormone but not very much)
What hormone gradually builds up prior to ovulation?
Oestrogen, then it rapidly subsides at the moment of ovulation
What hormone builds up after ovulation?
Progesterone, which drops off during menses
How does female sexual behaviour change across the menstrual cycle?
Women's sexual interest peaks around time of ovulation - more likely to initiate sex, have affairs, be aroused by pornography
Three phases of menstrual cycle?
Follicular (high in oestrogen)
Ovulatory (high in luteinising hormone)
Luteal (high in progesterone)
How does type of male faced preferred change across the menstrual cycle?
In follicular stage or ovulation stage, women more attracted to rugged features in men - square jaw, bushy eyebrows
How does the masculine/feminine face preference make sense evolutionarily?
Women prefer more masculine face when ovulating - healthier babies; but more feminine face the rest of the time - better provider, less violent
How does preference for smell differ in women over menstrual cycle?
Prefer smell of men who are genetically different at follicular stage - hybrid vigour
What is the effect of knocking out oestrogen receptors in female mice?
No interest in sex, no lordosis
What is lordosis?
A posture assumed by some female mammals during mating, in which the back is arched downward.
What's the difference between montane voles (sex fiends) and prairie voles (pair bonders)?
Only in prairie voles can oxytocin stimulate the release of dopamine - mesolimbocortical desire/reward pathway
What is oxytocin?
It's a nonapeptide, released from pituitary gland after signal from hypothalamus. It's important for:
Lactating, signals to let down milk
Contractions during labour
What is arginine vasopressin?
Nonapeptide, hypothalamus -> pituitary gland. It's important for:
Homeostatic affects of water retention in kidneys (yawn)
What interpersonal effects do oxytocin and vasopressin have?
They increase probability of forming pair bonds. In prairie voles, oxytocin important for females, vasopressin for males.
What role does oxytocin play in maternal care?
Helps lactating, but also induces pair bonding between mother and child
What is the effect of intranasal spray of oxytocin/vasopressin?
For women, oxytocin helps perceive emotionality in faces and remember faces
For males, vasopressin has same effect
How might oxytocin be linked to the effects of ecstasy?
The prosocial "love drug" effects of ecstasy may be mediated by oxytocin. If rats given oxytocin antagonist while on ecstasy, the cease prosocial behaviour - crawling on each other etc. Same goes for prosocial effects of alcohol.
How does romantic love correlate with activity in the dopaminergic system?
When subjects in fMRI asked to visualise someone they're passionately in love with, activation of mesolimbocortical DA reward pathway activated - same as with drugs