Lecture 8 - Sex and the brain Flashcards
1
Q
What is genotype?
A
the full set of genes that an organism possesses, different genes are organised into chromosomes
2
Q
How many chromosomes does an individual have?
A
- 46
- 23 from mother
- 23 from father
- a female has 2 X chromosomes and a male has 1 X and 1 Y
3
Q
Sex hormones?
A
- testosterone
- progesterone
- released in different proportions by both male and female reproductive organs
- all hormones come from cholesterol
4
Q
What are the 3 things we are a product of?
A
- genotype (XX or XY)
- action of sex hormones
- proportion of sex hormones
5
Q
The male and female brain?
A
- certain regions of the brain are ‘sexually dimorphic’
- the pre-optic nucleus is bigger in adult males and is related to testosterone levels and sexual activity in males
- the ventromedial nucleus of the hypothalalmus is involved in female sexual behaviour etc.
6
Q
Genetic mutations that affect sexual identity?
A
- usually the genotype and phenotype sex of an individual are aligned
- however there are a variety of genetic mutations that result in an ambiguous sexual phenotype e.g.
-> Turner’s syndrome
-> Congenital adrenal hyperplasia
-> Androgen insensitivity syndrome
7
Q
Female sexual behaviour in rats?
A
- mediated by the ventromedial region of the hypothalamus
- dependent on estradiol & progesterone
8
Q
Male sexual behaviour in rats?
A
- mediated by the pre optic area of the hypothalamus
- dependent on testosterone
- oxytocin release plays a role in pair bonding
9
Q
Women’s facial attractiveness and the fertile period?
A
- faces in fertile window and luteal phase are ranked as more attractive compared to faces in the follicular phase
- estradiol produces changes in face attractiveness
10
Q
What is the amygdala’s involvement in human sexual motivation?
A
- viewing erotic movies caused activity in the amygdala for men and women
- amygdala volume correlated with sexual interest in epilepsy patients who underwent temporal resection
- stimulation of amygdala in an epilepsy patient elicited sexual experience related sensations
- potentially related to amygdala’s processing of emotional arousal
11
Q
What is the role of the frontal lobe in sexual behaviour?
A
- amygdala and hypothalamus are both involved in sexual motivation and sexual behaviour
- lesions to frontal lobe cause:
-> loss of inhibition about sexual behaviour
-> erotomania = conditon in which people believe that another person is in love with them - lesions to the dorsolateral prefrontal cortex (DLPFC) = aggressive sexual behaviour
12
Q
What happens when the DLPFC is stimulated?
A
- p’s reported less intent to commit physical/ sexual assault
- p’s reported an increase in immorality of the act
- the increase in immorality rating explained the decrease in intent
13
Q
Sexual reward?
A
- successful completion of sexual behaviour (orgasm) is accompanied by a reward
-> dopamine release
-> relaxation due to oxytocin release - oxytocin may aid in pair bonding and is said to be involved in mother-infant bonds
14
Q
Differences in cognitive ability between sexes?
A
- women perform better on tests of verbal fluency
- men perform better on tests of spatial reasoning
15
Q
What are pheromones?
A
- they carry messages from 1 animal to the other and affect reproductive behaviour
- detected by olfactory receptors
- processed by the vomeronasal organ which activate the amygdala and the hypothalamus
