06: Social & Reproductive Behaviour - Part 2 (Social) Flashcards
What are maternal behaviours in rodents?
- gently pulling pups out during birth
- nursing
- nest building (vital in rodents, as pups are blind, cannot thermoregulate, and cannot release urine/faeces)
(Deacon, 2006) - licking pups’ anogenital region to stimulate urination and defecation
- retrieval of pups that leave/are removed from the nest
What are rodent maternal behaviours influenced by?
- Prenatal hormones (progesterone)
- Passage through the birth canal (Yeo & Keverne, 1986)
- Medial preoptic area (MPA), also involved in male sexual behaviour
- The VTA-NAC pathway (reward) makes encountering pups more rewarding than cocaine (Ferris et al., 2005)
Maternal behaviour and reward in human mothers
Being shown pictures of their own baby causes the reward system to light up (Bartels & Zeki, 2004)
Paternal behaviour
- Rare but occurs in some species
- More common in monogamous species (prairie voles), which share offspring care
Influences on paternal behaviour in prairie voles (vs promiscuous behaviour in meadow voles)
- size of MPA (causes male sexual behaviour) less sexually dimorphic in prairie voles than meadow voles
- MPA lesions disrupt parental behaviour in rats & prairie voles
What is affiliative behaviour?
- Positive social behaviour between two indivuals
What is affiliative behaviour influenced by?
Neuropeptides:
- Oxytocin (“love hormone”)
- Vasopressin (“possession hormone”)
- both produced in the hypothalamus
- released from posterior pituitary gland (hormone), or used as neurotransmitter
What is pair bonding (Rowan, 2004)?
- Monogamy
- Only occurs in 3-5% mammals
- Both parents raise children
Evidence for pair bonding (Young et al., 2008)
Sexually naïve prairie voles will pair bond in the lab whereas meadow voles will not
In the lab: administrating ‘pair bonding’ hormones
- Administrating vasopressin or oxytocin while animals are in each other’s presence
- Animals prefer the company of those they ‘bonded’ with (Sadino & Donaldson, 2018; Cho et al., 1999)
Neurobiology of pair bonds
- Pair bonding is associated with the density of VP receptors in reward areas of the brain
- OXT receptors are highly expressed in PFC and Nacc in prairie voles.
- Partner preference in prairie voles is disrupted after blocking OXT or VP receptors
Can we use these hormones to make promiscuous meadow voles monogamous?
- Yes
- Overexpression of VP receptor (in the ventral pallidum) enhanced mate preference in meadow voles (Lim et al., 2004)
Can we use OXT and VP to emulate pair bonding in humans?
- Probably, but manipulating OXT and VP carries ethical concerns
- Maternal & romantic love activate regions of the brain rich in VP and OXT receptors
What are prosocial behaviours?
- Positive social behaviours
- E.g. trust, altruism, empathy
What hormone is important for prosocial behaviour?
Oxytocin (OXT)
What does OXT increase (humans)?
Prosocial behaviours, such as…
- trust (Kosfeld et al., 2005)
- altruism (Marsh et al., 2015)
- empathy (Marsh et al., 2015)-
