SOCIAL BEHAVIOR
WHAT
IS
MONOGAMY?
Social monogamy – preference for a specific
partner (sexual exclusivity not essential)
Demonstrated by physical proximity
Monogamy also often associated with paternal
care
1
FIG 12.13
OXYTOCIN
AND
VASOPRESSIN
NEUROBIOLOGY
Oxytocin/
OF
PAIR-BONDING (“LOVE”)
vasopressin/ review
Why
y
were oxytocin
y
and vasopressin
p
originally identified as bonding hormones?
Species
differences…where are
monogamous and polygynous species
different?
2
Empty Cage
Tethered Partner
Animal
Tethered Stranger
Animal
Paraventricular nucleus
Supraoptic nucleus
AVP is also produced in:
Suprachiasmatic nucleus
(In males only):
Medial amygdala
Bed nucleus of the stria terminalis
3
OXYTOCIN AND VASOPRESSIN
RECEPTORS
OT has one receptor throughout the body,
expressed in many tissues including brain,
uterus, male reproductive tract, mammary
glands,
l d etc.
AVP has three receptor subtypes:
V1a, V1b, V2
4
COOL AVP
EXPERIMENTS
1) Injection of prairie vole V1a receptor genes
into mice
2) Up- and down- regulation of V1a receptors in
voles via viral vectors
3) Genetic studies of AVP receptor promoter
regions
5
VASOPRESSIN RECEPTOR VARIATION
(YOUNG, HAMMOCK)
Nair and Young, 2006
Nair and Young, 2006
Nair and Young, 2006
6
BOTH OT
AND
AVP
ARE INVOLVED IN
SOCIAL RECOGNITION AND MEMORY
OT knockout mice do not “remember” other
individuals.
Long history of studying AVP and social behavior
(David DeWied).
BOTH OT
AND
AVP
CAN INDUCE A PAIR-
BOND IN BOTH SEXES
Cho et al. 1999 – treatments given ICV
Administration of OT or AVP could induce a pairbond in either sex
Blocking OT or AVP could eliminate a pair-bond in
either sex
STRESS
AND
PAIR-BONDING
Formation
of a pair-bond also affected by
stress
Females that receive additional
corticosterone take longer to pair-bond;
remove their adrenal gland and they pairpair
bond faster
Males that receive additional
corticosterone or CRH take a shorter
time to pair-bond; remove their adrenal
gland and they pair-bond slower
7
REWARD COMPONENTS
Mating
induces dopamine release in both
males and females
Dopamine has multiple receptors (D1, D2,
D3, etc.)
Blocking
Bl ki th
these receptors
t
non-selectively
l ti l
reduces pair-bonding (haloperidol)
A non-selective DA agonist
(apomorphine) injected into the Nacc
induced pair-bonding (but not when
injected into the striatum) note: at low
doses but NOT high doses
High
doses probably activating D1 in
addition to D2
D2-type specific receptor agonist,
quinpirole,
q
p
induces partner
p
preferences
p
Blockade of D1 specifically does not
inhibit partner preferences
Activation of D1 prevents quinpiroleinduced preferences
Overall message:
D2 activation = partner preference
D1 activation = no partner preference
8
Lateral septum; social memory
Olfactory system
MeA
VTA, Nucleus accumbens shell
Ventral pallidum
MdThal
Colocalization of V1a receptors with dopamine D2 receptors
1) Both oxytocin and vasopressin are necessary in both
sexes.
2) However, vasopressin may be more “important” in males
and oxytocin is more “important”
important in females.
females
3) Dopamine is also a critical component of pair-bonding in
both sexes.
4) Pair-bonding can be modulated by stress hormones (i.e.
corticotropin-releasing hormone).
Photo: A. Williams/Sacramento Bee
9
TITI
MONKEYS
Monogamous
Strong
primate
pair-bond between male and
female
carry infants over 90% of time
When separated, pair-mates have
increased cortisol levels
When infant is separated, neither
father nor mother has elevated cortisol
Infant has elevated cortisol when
separated from father but not from
mother
Males
Early environment
can affect the
ability to form
social bonds.
10
MODELS OF EFFECTS
OXYTOCIN SYSTEMS
Early
Handling
OF
EARLY EXPERIENCE
Parental
Stimulation
O t i
Oxytocin
ON
Social
Behavior
Anxiety
O t i
Oxytocin
Based on models by Levine, Denenberg, Meaney, Champagne,
Francis, Pedersen, Boccia, etc.
MAN1
MAN0
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HANDLING EFFECTS
ON
MALE ALLOPARENTAL CARE
Bales et al., Developmental Psychobiology,
PARTNER PREFERENCE TEST
Behaviors Scored
Location
Empty
Contact
Partner
Stranger
Empty cage
Partner’s cage
St
Stranger’s
’ cage
No contact
Partner contact
Stranger contact
12
HANDLING EFFECTS
ON
FEMALE PAIR-BONDING
Bales et al., Developmental Psychobiology,
HANDLING EFFECTS
ON
ANXIETY
Bales et al., Developmental Psychobiology,
13
FEMALE OT
MALE OT
RECEPTOR BINDING
RECEPTOR BINDING
14
OT
PRODUCTION IN THE
SON
15
PHARMACOLOGICAL MANIPULATION
OXYTOCIN - METHODS
OF
On
day 1 of life, infants receive an
injection of either:
1) Oxytocin (OT)
2) Oxytocin antagonist (OTA)
3) Saline (SAL)
4) They are handled only (HAN)
Tested: parental care, partner
preference, plus-maze, and intrasexual
aggression
EXPOSURE
TO
OTA
REDUCES ALLOPARENTAL
CARE IN MALES
Proportion Displayin
ng Behavior
0.8
0.7
a
Males - Day 21
a
0.6
0.5
Parental
0.4
b
z
Attack
0.3
0.2
y,z
0.1
y
0
CTL (n = 34)
OT (n = 18)
OTA (n = 17)
Bales et al., Developmental Psychobiology,
OT
SHOWS A DOSE-RESPONSE IN FEMALES
0.07
Proportion time spen
nt in contact
Partner
0.06
n = 26
b
n = 14
0.05
n = 15
n = 14
0.04
0.03
n = 12
Stranger
a,b
a
a
*
0.02
a
0.01
0
Saline
1mg/kg
2mg/kg
4mg/kg
8mg/kg
Bales et al., Hormones and Behavior,
16
MALE
DOSE-RESPONSE
0.16
Partner
Stranger
Proportion time in c
contact
0.14
0.12
01
0.1
0.08
*
0.06
*
0.04
0.02
0
Saline
V1A600RECEPTORS
1mg/kg
2mg/kg
4mg/kg
CHANGE IN MALES
OT
OTA
Males
Change from litte
er CTL (DPM)
400
*
200
0
-200
*
*
-400
-600
*
-800
VP
MeA
MPOA
BNST
LS
CgCtx
MdThal
Bales et al., Neuroscience 2007
INTRANASAL OXYTOCIN
Available for $29.95
on Amazon
Chronic intranasal
OT (not liquid trust
brand) is in clinical
trials for use with
kids with autism
No previous animal
testing for longterm effects
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