Behavioral Neuroscience Introduction to Neuroscience:
Lecture 4: Animal models of social disorders
Tali Kimchi Department of Neurobiology [email protected]
* Presentation Materials for Personal Use ONLY
♂ ♀ XY
XX
Estradiol &
Progesterone
Testosterone &
Estradiol Organization
Dimorphism of the brain: differentiation and activation
-
Bipotential gonad
SRY gene
+
Ovary Testis
Estradiol &
Progesterone
Sex-specific behaviors
Activation Testosterone &
Estradiol
Organization
(permanent changes)
Factors regulating sexual dimorphic (reproductive) behaviors
-Sex hormones (organization and activation stage)
- Sex chromosomes (X/Y)-linked genes
- Imprinting genes (maternal and paternal genes
- Environmental factors
Exposure different levels of testosterone in uterus on female/male behavior
High level of testosterone
in the surrounding
Low level of testosterone
in the surrounding High level of testosterone
in the surrounding
Low level of testosterone
in the surrounding
Rayan and Vandernbergh 2002; Neuroscience and Bioheavioral Reviews
Exposure to testosterone in uterus on female behavior
Rayan and Vandernbergh 2002; Neuroscience and Bioheavioral Reviews
Effect of prenatal stress on sexual dimorphism in brain and behavior
The Medial Preoptic Area (MPOA) is activated by testosterone and is essential to the activation of male sexual behavior
Castration Microinjection of testosterone into the MPOA
Reinstate sexual behavior
Abolish of sexual behavior
MPOA lesion Abolish of sexual behavior
♂ ♀
Anderogen Receptor expression in the MPOA
Intact male Sexual behavior Increase neuronal firing rate in the MPOA
Sex-specific pheromone stimuli or mating behavior
Induce c-fos in MPOA of both males and females (c-fos is immediate early gene, indirect molecular marker of neuronal activity)
Shah et al 2004; Neuron
SDN-POA control male
SDN-POA stressed male
Anderson et al 1985; Brain Research
Effect of prenatal stress on sexual dimorphism in rat brain
ES: Environment stress (change in lighting/ temperature)
NS: nutritional stress (50% of total food of control males)
Mueller and Bale 2008; JNS
C: control;
Prenatal stress during (E) early, (M) mid or (L) late gestation
Suspension tail assay Force swim test
Mueller and Bale 2008; JNS
The control of pheromone signals on dimorphic behaviors
Chemical (odor) signals that are emitted by animals to communicate information to their own species
What are pheromones?
What are pheromones?
Pheromone signals are largely involved in the regulation of social and reproductive behaviors in most animals (including in human)
Attracting mate partner Pups recognition Male territoriality
Primer effects: induce sequence of slow long-lasting physiological and neuroendocrine responses
Releaser effects: induce relatively rapid, fixed, behavioral responses
Ultrasonic vocalization in the presence of female
Aggressive behavior toward intruder male
Mating behavior
Pheromone effects in rodents
Aggressive behavior of lactating female
Maternal behavior (e.g. pups retrieval)
Bruce effect: Recently mated female will return to estrous if exposed to strange male (pregnancy block)
Whitten effect: Induction of estrous in group-housed females by exposing to male (urine)
Lee-Boot effect: Grouping several (8-12 individuals) females in a cage results in suppression of their estrous cycles
Vandenbergh effect: Puberty acceleration caused by exposure to male, during female development.
Puberty-delay caused by group-housed females.
Endocrine effects: Intact male exhibit LH surge Following exposure to female mice. Female exhibit LH surge in response to male or its bedding
The olfactory systems
Liman et al. 1999
TRPC2 expression in the VNO
VNO
OB
Detection of chemosensory signals in mice
Typical male-female reproductive behaviors
♂
♀
Aggressive behavior Sexual behavior
TRPC2 mutant female (brown) with normal male (black)
Sexual behavior of TRPC2-KO lab female
Kimchi et al. 2007; Nature
♂
♀ WT
WT
TRPC2-KO
Male-typical sexual behavior in TRPC2-KO lab females
An
ima
l m
ou
nti
ng
(%
) M
ou
nti
ng
tim
e (
se
c)
Pe
lvic
th
rus
tin
g (
se
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♀
Kimchi et al. 2007; Nature
Female
Male
Social behavior under semi-natural environment
control
mutant
Maternal Behavior
Failure to discriminate between male and female
?
Male-typical sexual behavior (courtship and mounting behaviors)
Female mutant
Normal male
Female-typical behavior (maternal behavior)
Summary-part 1: Behavioral phenotype of TRPC2-KO lab females
Old model
♀
♂ ♂
New model
♀
4 mutant males
2 control (normal) males
Kimchi et al. 2007; Nature
Stowers et al 2002; Science
Social and sexual behaviors of male mutant mice
Failure to discriminate between male and female
?
Aggressive behavior
Normal testosterone level
Model: Pheromone inputs repress neuronal circuit for male-typical sexual behavior in females
♂ Sex-specific
pheromone signals
♀ Sex-specific pheromone signals
Dulac and Kimchi, 2007; CONB
♂
Pheromone inputs repress maternal behavior in males
TrpC2-/- mutant male retrieve newborn pups back to nest
TrpC2-/- mutant males exhibit reduce male-typical (infanticide) behavior and elevated female-typical (pup nursing) behavior
Attacking pups Nursing pups
Social and sexual behaviors of male mutant mice
Failure to discriminate between male and female
?
Aggressive behavior
Normal testosterone level
Female-typical behavior (pup caring / nursing behavior)
Donaldson and Young 2008; Science
Oxytocin and Vasopressin
Isoleucine
Phenylalanine
Argenine
Leucine
Neurophysiology of Oxytocin (OXT) and arginine vasopressin (AVP)
Oxytocin KO mouse model
Ferguson et al 2001; J Neuroscience
Summery:
OTKO mouse fail to habituate to, or recognize, a stimulus mice even
after repeated exposures
The deficit in social recognition in OTKO mice represents a defect in
the initial processing of olfactory cues and not in the recall of the
previously stored memory
OT must be present in the MeA during the initial social exposure for
the proper processing of the olfactory information and the
development of the social memory
Oxytocin effects on humans
The role of OT and VPA in social behavior of Bi-parental rodent
The neuronal basis of pair bonding
Pair bonding and social behavior in voles
Prairie voles
Highly social
Monogamous
Spend more than 50% of
their time interacting with
other prairie vole
• Montane voles
• Avoid social contact except for
the purpose of mating
• Polygamous
• Spend only around 5% of their
time socially interacting.
Hemanth et al 2006 Physiology
Prairie voles have high levels of OT receptor in the nucleus accumbens and the basolateral amygdala relative to montane voles
Montane voles have high levels of receptors in the lateral septum.
Prairie voles have high densities of
the V1a subtype of the AVP receptor in the ventral pallidum and the medial amygdala compared with montane voles.
Montane voles have much higher levels of receptors in the lateral septum than do prairie voles.
Oxytocin and parental behavior in Prairie voles
Oxytocin receptor level
High
Parental behavior
Low
% o
f fe
male
show
ing n
urt
uring b
ehavio
r
Ross and Young, 2009
Prairie vole
Montane vole
Oxytocin and partner preference in Prairie voles
Transgenic mice expressing
the V1aR of the prairie vole
Young et al 1999; Nature
Vasopressin receptor and pair bonding in Prairie voles and Montane voles
V1aR expression
Prairie
Montane
Hammock & Young, 2005 Science
Meadow voles (Microtus pennsylvanicus) Prairie voles (Microtus ochrogaster)
Young et al. 1999 Nature
♂
Promiscuous social behavior
Monogamous social behavior
“A single gene can turn the Don Juan of voles into an attentive home-loving husband”. BBC news
The “Fidelity gene”
Walum et al 2008, PNAS
?
The genetic basis for pair bounding
Vasopressin R1a
The use of mouse models to study neuropsychiatric disorders (e.g. autism spectrum disorders)
Kanner L. Autistic disturbances of affective contact.
Nervous Child 2, 217-250 (1943)
2011-2013 DSM-V: classified better the symptoms (criteria of diagnostics)
• Complex genetic disorders (i.e. interactions between many genes and environmental factors)
• Few hundreds of genes were associated with autism
• No biomarker for autism diagnostic: diagnostic is based only behavioral symptoms (~1.5-3 years old)
2014: 1 in 68 children
(1 in 42 boys and 1 in 189 girls)
Autism Spectrum Disorder
Must meet criteria A, B, C, and D:
A. Persistent deficits in social communication and social interaction
across contexts, not accounted for by general developmental delays, and
manifest by all 3 of the following:
1. Deficits with social initiation and responses
2. Deficits in non-verbal communication
3. Deficits in social awareness and insight, as well as with the broader
concept of social relationships
B. Restricted, repetitive patterns of behavior, interests, or activities as
manifested by at least 2 of 4 symptoms:
1. Atypical speech, movement, and play
2. Preocupations with objects or topics
3. Rituals and resistance to change
4. Atypical sensory behaviors
C. Symptoms must be present in early childhood (but may not become fully
manifest until social demands exceed limited capacities)
D. Symptoms together limit and impair everyday functioning.
American Psychiatric Association DSM-5 Development (May, 2013)
http://depts.washington.edu/dbpeds/Screening%20Tools/DSM-5(ASD.Guidelines)Feb2013.pdf
http://depts.washington.edu/dbpeds/Screening%20Tools/DSM-5(ASD.Guidelines)Feb2013.pdf
Stoner et al 2014 New England Journal of Medicine
The use of mouse models to study neuropsychiatric disorders (e.g. autism spectrum disorders)
Recent mouse history
W.E. Castle C.C. Little
Fancy mouse breeding - Asia, Europe
(last few centuries)
Retired schoolteacher Abbie Lathrop
collects and breeds these mice
Granby, MA – 1900
Castle, Little and
others form most
commonly used
inbred strains
from Lathrop stock
(1908 on)
• Mammalian system - close to human
(genetically, physiologically and morphologically)
• Small and easy to handle
• Easy to house and breed
• Inexpensive
• Can be genetically manipulated
• There is a lot of biological knowledge (e.g. Jax lab database, MGI, Allen brain atlas)
Mouse sequence reveals great similarity with the human genome
Extremely high conservation: 560,000 “anchors”
Mouse-Human Comparison
both genomes 2.5-3 billion bp long
> 99% of genes have homologs
> 95% of genome “syntenic”
Steps towards a Transgenic Model
Working hypothesis
Gene Construct
Insertion into an early embryonic stage
Screening for transgenic animals
Profiling of expression pattern
Phenotyping
Model Validation / Experimentation
Transgenic Animals: Definition
Mutant animals carrying experimentally introduced foreign
genetic elements in all their cells, including the germline
Transgenic:
Introduction of foreign or altered gene: transgenic Over-expression, mis-expression, dominant-negative
Normal allele also present - product from two alleles
Knockout:
Replace normal with mutant allele: Gene knock-out - removal of a part of or a whole gene
No normal allele - product of manipulated allele only
Transgenic and Knockout Animals
Institute of Laboratory
Animal Science
University of Zurich
Analyse the progeny
by PCR or Southern blotting
Generating Transgenic Mouse Model
• Transgenic construct: gene size • Varied expression levels: random integration, copy number • F0 mice may be mosaic • Lethality due to transgene integration or expression
Generating Knockout Mouse Model
Social and reproductive, Stress-anxiety, Learning and memory, Orientation,
Motor and cognition skills, sensory perception, etc
Behavioral phenotyping of the transgenic mouse model
Knockout mouse model
Voineagu et al 2010; Nature
Autism
Schizophrenia
Autism &
Schizophrenia
McCellan & King 2010; Cell
Common genetic basis to Autism and Schizophrenia
Silverman et al 2010;
Nature Reviews Neuroscience
Silverman et al 2010; Nature Reviews Neuroscience
Studying autistic-related behaviors in mouse models
Autism Spectrum Disorders
Main characteristics:
Social and Communication Deficits
Fixed Interests (Rigidity in habits)
Stereotypic (repetitive) Behaviors
Symptoms must be present in early childhood
Social behavior test for mice
Cognitive rigidity Wet T-maze assay
Stereotypic behavior
Cryan and Holmes, 2005
Suggested behavioral assays in animal models relevant to anxiety/stress disorder
Examples of automated behavioral phenotyping systems for rodents to evaluate locomotion, anxiety, memory
