Affiliative Behaviour Pair Bonding & Reproductive Behaviour

Question 1

What is pair bonding?

Answer 1

The process of attachment

Question 2

What 3 peptide hormones are typically associated with pair bonding?

Answer 2

Dopamine
Oxytocin
Arginine vasopressin

Question 3

Give 3 pieces of evidence for the role of hormones.

Answer 3

• Mating leads to release of OT + AVP in brain
• Experimental administration of OT into brain induced bonding in female prairie voles even without mating
• Blocking OT receptors with OT antagonists inhibited female partner preference

Question 4

In male prairie voles, what is the most necessary hormone for pair-bond formation?

Answer 4

Arginine Vasopressin

Question 5

In female prairie voles, what is the most necessary hormone for pair-bond formation?

Answer 5

Oxytocin

Question 6

What are the differences between prairie + montane voles?

Answer 6

• Nucleus accumbens of hypothalamus + prefrontal cortex of prairie vole are rich in oxytocin receptors, whereas montane vole has few receptors in these areas
• Ventral pallidum region of hypothalamus is rich in AVP receptors in prairie voles, whereas in the montane vole it is not

Question 7

What is the role of oxytocin?

Answer 7

Facilitates trust + attachment (love chemical)

Question 8

What is the role of arginine vasopressin?

Answer 8

Similar to OT (only differs by 2 amino acids)
Facilitates attachment

Question 9

What does the mesolimbic ‘reward circuit/pathway’ comprise of?

Answer 9

• Ventral tegmental area
• Nuclues accumbens
• Prefrontal cortex

Question 10

What 2 chemicals work together in the formation of pair bonds through reward pathway?

Answer 10

• Dopamine
• Oxytocin

Question 11

What role does the ventro-medial nucleus play in males?

Answer 11

• Vocalisations
• Scent marking
• Mounting behaviours

Question 12

What role does the ventro-medial nucleus play in females?

Answer 12

• Mediates lordosis (arched-back posture)

Question 13

What happens to the behaviour of ADULT male mice when castrated?

Answer 13

• Show no mounting behaviour as no testes to produce testosterone

Question 14

What happens to behaviour if you treat ADULT castrated mice with testosterone?

Answer 14

• Mounting behaviour is restored

Question 15

What happens if you castrate mice at BIRTH?

Answer 15

• No testosterone production
• When treated with testosterone, still fail to display mounting behaviour
• When treated with oestrogen, display lordosis

Question 16

What happens if you castrate mice at birth, treat them with testosterone, let 5em mature & then treat them with oestrogen?

Answer 16

• No lordosis
• Mounting behaviour present

Question 17

What do sex steroids present at birth determine?

Answer 17

Pattern of behaviour

Question 18

What do sex steroids present as adults determine?

Answer 18

When behaviour is expressed

Question 19

What happens when you spay an adult rat and treat it with oestrogen? What happens when then treated with testosterone?

Answer 19

• Lordosis
• No sexual behaviour

Question 20

What happens when you spay a newborn rat and treat it with oestrogen? What happens when then treated with testosterone?

Answer 20

• Lordosis
• No sexual behaviour

Question 21

What happens when you spay a newborn rat and treat it with testosterone, let her mature, treat with oestrogen & then treat with testosterone again?

Answer 21

• No lordosis
• Mounting behaviour - brain has been masculinised

Question 22

What part of the brain is essential for the expression of male sexual behaviour in all vertebrate species?

Answer 22

• Medial pre optic area (MPOA) of the hypothalamus
• Specifically, the sexually dimorphic nucleus (SDN)