Lecture 6 - Sex Differences 2 Flashcards

1
Q

Outline sex difference in behaviour and relevant neural substrates Arnold 2009 XX chromosome

A

XX -> ovaries -> feminisation -> estradiol and progesterone activation

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2
Q

Outline sex difference in behaviour and relevant neural substrates Arnold 2009 XY chromosome

A

XY -> testes, testosterone estradiol -> masculinisation defeminisation -> testosterone activation

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3
Q

Introduction sex differences

A

Overlap behaviours male and female

Identification sex differences acknowledges mean differences
Predict very little specific individuals

Sex differences other behaviours less marked those in core sexual identity and orientation

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4
Q

Where are the largest differences found in sex differences

A

Range differences within each sex larger differences between sexes
Largest behavioural sex differences seen in sexual orientation and core sexual identity
Differences not absolute

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5
Q

Determinants of sex differences in behaviour and cognition

A

Sex genes activity different sex hormones and environment/experience all factors differ between males and females factors interact effects on brain result sex differences
Partly mediated sexual dimorphisms in brain or CNS
Result from exposure identical (sexually homomorphic) brain substrates to female or male sex hormones/experiences

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6
Q

Outline mating behaviour

A
Sexually dimorphic 
Only act that way 
No fluidity 
Lordosis response 
Hormonal control and relevant neural sexual dimorphisms
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7
Q

What are the 3 factors required for heterosexual mating behaviour in mammals

A

Sufficient level attraction both sides

Sufficient level porceptivity - willingness to mate

Sufficient receptivity - ability mate

Not met no mating

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8
Q

What occurs in heterosexual mating behaviour mammals once 3 factors required

A

Appetitive phase behaviour - courting
Enter consummation phase compilation - enter mounting, intro mission, ejaculation
Lordosis response

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9
Q

How is heterosexual mating activation controlled by sex hormones

A

Testosterone necessary for males
Castrated can’t mate
Female mating isn’t as hormonal dependent
Females dependent attractivity proceptivity and receptivity under control hormonal cycle - menstrual

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10
Q

How important is the role of the reproductive and hormonal cycle in female mammals

A

Important determining sexual behaviour
Particularly in rodents
But gets weaker in primates and weak in humans

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11
Q

What are reproductive and hormonal cycles in female mammals controlled by

A

Hormone release by anterior pituitary gland
Folic stimulating hormone to ovary and growth of follicle triggering cycle
Only 1 point around ovulation animal can procreate
Cycle accompanied changes in hormones

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12
Q

When is pregnancy possible in reproductive and hormonal cycles in female mammals

A

Pregnancy only possible during certain time of cycle around ovulation
Oestrogen and progesterone levels are high
Around ovulation - behavioural Estella
Except for primate females who can mate any time

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13
Q

How are female behaviours linked repductive chcle

A

Linked reproductive cycle and controlled by hormonal fluctuations

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14
Q

Are primates still influenced by reproductive and hormonal cycles

A

Even primates attractiveness receptivity and proceptivity appear be modulated by hormonal cycle

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15
Q

What else May hormonal cycles influence

A

Influence behavioural cognitive and affective functions that not directly related to reproductive behaviour

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16
Q

Outline spinal mechanisms relevant to make copulating behaviour in rats - Breedlove and Arnold 1980

A

Spinal nucleus of bulbocavernosurs - SNB

Collection motor neurons in lower lumbar spinal cord; controls bulbocavernosus muscle at base of Lenin’s

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17
Q

Why are motorneurons and muscles necessary in spinal nucleus of bulbocavernosurs Breedlove and Arnold 1980

A

Motor neurons and muscles necessary for normal penile reflexes important successful copulation

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18
Q

What are the direct masculinising effects testosterone

A

Organisational effects testosterone way effects indirect
Testosterone receptors muscle cells then release trophies factored
Support neurons from spinal cord
Don’t have testosterone these neurons and fibres wither away

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19
Q

Interaction nature and nurture testosterone exerts some masculinising effects SNB and sexual behaviour via rat mother - Moore 1992

A

Rat Mother’s are stimulated lick their male pups more often than females because of testosterone in urine
Licking contributes normal male sexual behaviour and normal number SNB neurons

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20
Q

Sex circuits relevant to mating behaviour in rodents

A

Sex circuits constrain sex hormone receptors
Critical sexually dimorphic mating testosterone for male
Estradiol and progesterone for female

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21
Q

Outline sexually dimorphic nucleus of preoptic area SDN-POA relevant mating behaviours in rodents

A

SDN POA and posterodorsal media amygdala and medial proptic area
Parts bigger in males
Destroy it males don’t copulate
Activated by mating supported increase production in gene association between these areas influence testosterone in copulation mediation

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22
Q

Outline ventral nucleus of hypothalamus relevant mating behaviours in rodents

A

Important females
Medial amygdala both males and females
Dimorphism acts different males to females

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23
Q

Outline sexually dimorphic components relevant mating behaviours in rodents

A

SDN POA - masculinised testosterone during critical perinatal period

MePD volume and cell size depend testosterone action adulthood - activational effect

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24
Q

Outline sexual dimorphisms in humans to rodent SNB

A

Ventrolateral cell group of Onufs nucleus in human spinal cord
Bigger males higher motor neuron count

25
Q

Outline Fliers and Swaab 1985 study sexual dimorphisms in human preoptic area of hypothalamus

A

One nucleus in POA hypothalamus larger in volume and cell number in males
Nucleus SDN sexually dimorphic. Declines with age

26
Q

Outline Allen et al 1989 study sexual dimorphisms in human preoptic area of hypothalamus

A
4 nuclei in POA 
INAH 1-4 
INAH1 correspond SDN Fliers 1985 
Not differ between sexes 
INAH4 not differ 
INAH2-3 not differ between homosexual men and heterosexual women
27
Q

What does INAH stand for according to Allen et al 1989

A

Interstitial nuclei of anterior hypothalamus

28
Q

What occurs result INAH2-3 according to Allen et al 1989

A

INAH2-3 not differ between homosexual men and heterosexual women

29
Q

Outline LeVay 1991 study on sexual dimorphisms in human preoptic area hypothalamus

A

Relationship between size nuclei and sexual preference no significant sex differences INAH1,2,4
INAH3 larger heterosexual men than women
Did not differ between homosexual men and heterosexual women

30
Q

What are the effects of INAH3 according to LeVay 1991

A

INAH3 larger heterosexual men than women

Did not differ between homosexual men and heterosexual women

31
Q

What areas are critical for sexually dimorphic mating female lordosis

A

Ventromedial nucleus of hypothalamus
Contain sex hormone receptors stimulation critical for sexually dimorphic behaviour
Activational effects sex hormones

32
Q

Outline role pheromones in mating behaviour

A

Brain circuits determining male or female behaviour rely dormant both brain
Activated pheromones - hormone like releases urine act on cumbersome nasal organs
Or human sweat

33
Q

Conclusion sexually dimorphism

A

Exist CNS implicated sexually dimorphic mating

Neural sexual dimorphism’s contribute to behavioural sexual dimorphisms

34
Q

Conclusions of organisational hypothesis

A

Some aspects sexually dimorphic mating behaviour and relevant neural sexual dimorphisms show in rodents
Involve organising effects sex steroids during critical developmental periods

35
Q

What does aggressive behaviour involve

A

Threat or attack
Not unitary concept
Some aspects strongly related reproductive behaviour - competition mating, protection offspring

36
Q

Outline Rodents aspects of aggression

A

Aggression mediated brain regions overlap with regions implicated reproductive behaviour

Sex dependent (dimorphic) under influence sex steroids (role testosterone)

37
Q

Outline humans aspects aggression that are sexually dimorphic

A

Effect sizes different ratings aggressiveness based competitiveness

38
Q

Outline how studying heterosexual and homosexual males in aggression is effective

A

Aggression levels same but experiences may be different
Can separate influence environment to hormones
Small effect size males be more aggressive
Larger difference heterosexual and homosexual males

39
Q

How does testosterone contribute to sex differences

A

By acting on brain

40
Q

What other factors contribute to sex differences

A

Men on average physically stronger

41
Q

Female advantages of sex differences in cognitive functions

A

Perceptual speed
Visual memory
Verbal fluency
Fine motor skills

42
Q

Male advantages of sex differences in cognitive functions

A
Spatial rotation 
Paper folding 
Target accuracy 
Embedded figures 
All spatial tasks
43
Q

Outline male cognitive advantages identified in rodents

A

Place learning and navigation

44
Q

Outline cognitive abilities identified in prairie voles

A

Evolved due to ecological pressures
Only exist polygamous species makes Range more widely than females
Correlate larger hippocampus - critical for spatial learning in males

45
Q

Outline monogamous species and sex differences in cognitive abilities

A

Monogamous species - similar abilities in sexes

46
Q

Outline sex differences in cognitive functions in hippocampus

A

Differences found in rats and men
Rodents hippocampus larger in males
Humans hippocampus smaller in males

47
Q

Outline fMRI study on sexual differences in cognitive abilities

A

Suggests men may use their hippocampus more than women

To navigate a virtual maze for spatial navigation

48
Q

Outline navigating maze study on sexual differences in cognitive abilities

A

Navigate maze using joy stick activated in women frontoparietal activation
Linked egocentric strategy - going left or right
Men linked hippocampus - external cues

49
Q

Outline Examplar study in rats by Markowska 1999 water maze

A

Find hidden platform using hidden spatial cues in maze
Inductive measure - measured distance and time
Males better faster and travel less. Efficient
Better place learning and navigation in males

50
Q

Outline Astur 1998 Exemplar study in humans

A

Virtual water maze on computer

Males more efficient spatial learning and navigation

51
Q

Outline sex differences in mental rotation and water jar task - Gladue and Bailey 1995

A

Mental rotation: 20 items 2 correct and 2 incorrect choices
Water jar task: 10 items jar tilted different angles. Ppts draw line assuming jar half full
Effect size .5 mental rotation
.4 water jar

52
Q

Outline William the Worm task by Buckley and Bast 2018

A

Virtual maze task rapidly learn where William Worm hidden in lawn
Large sample 80% power
Significant difference
Effect size .5

53
Q

Compare William the worm task to mental rotation performance

A

Men on average better both
Performance measures place learning and mental rotation not significantly correlate
Implies sex differences 2 tests likely rely on different neuropsychological mechanisms

54
Q

Other reasons for men having good performance on William the Worm task

A

People played video games performed better - mainly men

55
Q

Why do cognitive sex difference only allow for very limited predictions of cognitive abilities

A

Men better rapid place learning or mental rotation test with effect size .5
Means any randomly picked male probability him being better any randomly picked female 64%
No average sex difference probably 50>
Concerning effect sizes and their interpretation compare

56
Q

Why are sex differences in brain sites not primarily associated with sexual behaviour

A

Brain weight and volume also higher in males = abolished terms and relative body size
Neuroanatomical sexual dimorphisms contribute sex differences in behaviour and cognition not known

57
Q

Sex differences in the incidence of neuropsychiatric diseases of affective disorders and anxiety

A

Affective disorders and anxiety exception mania more prevalent women

58
Q

Sex differences in the incidence of substance abuse and antisocial personality

A

Substances abuse and antisocial personality more prevalent in men

59
Q

Sex differences in the incidence of autism

A

Autism more prevalent males 4:1