22 Neurobiology of sex, attachment and empathy Flashcards
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?
Hypothalamus
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?
Oestrogen
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
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
What systems are involved in the functioning of mirror neurons?
Visual input from posterior superior temporal sulcus; frontal lobe pre-motor cortex structures, parietal lobe structures
Why are mirror neurons important in theory of mind?
They allow you to model the behaviours of others and attribute intentions to those behaviour
What systems are involved in the functioning of mirror neurons?
Visual input
What part of the brain responds to pain?
Anterior cingulate cortex
How does the brain function of seeing someone in pain differ between psychopaths and control?
Control group has activation of somatosensory cortex (related to body part in pain) and anterior cingulate cortex (related to pain) - brain replays the pain. For psychopath, reward pathways are activated.
What does the Heider-Simmel theory of mind demonstration suggest about attribution of intentionality?
Humans have innate tendency to attribute intentionality - even to inanimate shapes
