Introduction to Neuroscience: Behavioral Neuroscience

Transcription

1 Introduction to Neuroscience: Behavioral Neuroscience Lecture 4: Animal models of social disorders Tali Kimchi Department of Neurobiology * Presentation Materials for Personal Use ONLY

2 Dimorphism of the brain: differentiation and activation XY Bipotential gonad XX Testis + SRY gene - Ovary Testosterone & Estradiol Organization (permanent Organization changes) Estradiol & Progesterone Testosterone & Estradiol Activation Sex-specific behaviors Estradiol & Progesterone

3 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

4 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 Low level of testosterone in the surrounding High level of testosterone in the surrounding Rayan and Vandernbergh 2002; Neuroscience and Bioheavioral Reviews

5 Exposure to testosterone in uterus on female behavior Rayan and Vandernbergh 2002; Neuroscience and Bioheavioral Reviews

6 Effect of prenatal stress on sexual dimorphism in brain and behavior

7 The Medial Preoptic Area (MPOA) is activated by testosterone and is essential to the activation of male sexual behavior Shah et al 2004; Neuron Anderogen Receptor expression in the MPOA Castration Abolish of sexual behavior Microinjection of testosterone into the MPOA Reinstate sexual behavior MPOA lesion Abolish of sexual behavior 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)

8 Effect of prenatal stress on sexual dimorphism in rat brain SDN-POA control male SDN-POA stressed male ES: Environment stress (change in lighting/ temperature) NS: nutritional stress (50% of total food of control males) Anderson et al 1985; Brain Research

9 Suspension tail assay Force swim test C: control; Prenatal stress during (E) early, (M) mid or (L) late gestation Mueller and Bale 2008; JNS

10 Mueller and Bale 2008; JNS

11 The control of pheromone signals on dimorphic behaviors

12 What are pheromones? Chemical (odor) signals that are emitted by animals to communicate information to their own species

13 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

14 Pheromone effects in rodents Releaser effects: induce relatively rapid, fixed, behavioral responses Ultrasonic vocalization in the presence of female Aggressive behavior toward intruder male Mating behavior Aggressive behavior of lactating female Maternal behavior (e.g. pups retrieval) Primer effects: induce sequence of slow long-lasting physiological and neuroendocrine responses Bruce effect: Recently mated female will return to estrous if exposed to strange male (pregnancy block) Lee-Boot effect: Grouping several (8-12 individuals) females in a cage results in suppression of their estrous cycles Whitten effect: Induction of estrous in group-housed females by exposing to male (urine) 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

15 The olfactory systems

16 Detection of chemosensory signals in mice OB VNO TRPC2 expression in the VNO Liman et al. 1999

17 Typical male-female reproductive behaviors Aggressive behavior Sexual behavior

18 Sexual behavior of TRPC2-KO lab female TRPC2 mutant female (brown) with normal male (black) Kimchi et al. 2007; Nature

19 Pelvic thrusting (sec) Mounting time (sec) Animal mounting (%) Male-typical sexual behavior in TRPC2-KO lab females WT TRPC2-KO WT Female Male Kimchi et al. 2007; Nature

20 Social behavior under semi-natural environment

21 Maternal Behavior control mutant

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23 Summary-part 1: Behavioral phenotype of TRPC2-KO lab females Male-typical sexual behavior (courtship and mounting behaviors) Female mutant Normal male? Failure to discriminate between male and female Female-typical behavior (maternal behavior)

24 Old model New model

25 2 control (normal) males 4 mutant males Kimchi et al. 2007; Nature Stowers et al 2002; Science

26 Social and sexual behaviors of male mutant mice Aggressive behavior Failure to discriminate between male and female? Normal testosterone level

27 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

28 Pheromone inputs repress maternal behavior in males TrpC2-/- mutant male retrieve newborn pups back to nest

29 TrpC2-/- mutant males exhibit reduce male-typical (infanticide) behavior and elevated female-typical (pup nursing) behavior Attacking pups Nursing pups

30 Social and sexual behaviors of male mutant mice Aggressive behavior Failure to discriminate between male and female? Female-typical behavior (pup caring / nursing behavior) Normal testosterone level

31 Oxytocin and Vasopressin Donaldson and Young 2008; Science

32 Neurophysiology of Oxytocin (OXT) and arginine vasopressin (AVP) Phenylalanine Argenine Isoleucine Leucine

33 Oxytocin KO mouse model

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36 Ferguson et al 2001; J Neuroscience

37 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

38 Oxytocin effects on humans

39 The role of OT and VPA in social behavior of Bi-parental rodent

40 The neuronal basis of pair bonding

41 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.

42 Hemanth et al 2006 Physiology

43 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.

44 % of female showing nurturing behavior Oxytocin and parental behavior in Prairie voles Parental behavior Oxytocin receptor level Low High Ross and Young, 2009

45 Oxytocin and partner preference in Prairie voles Prairie vole Montane vole

46 Vasopressin receptor and pair bonding in Prairie voles and Montane voles V1aR expression Transgenic mice expressing the V1aR of the prairie vole Montane Prairie Young et al 1999; Nature

47 Hammock & Young, 2005 Science

48 The Fidelity gene A single gene can turn the Don Juan of voles into an attentive home-loving husband. BBC news Meadow voles (Microtus pennsylvanicus) Prairie voles (Microtus ochrogaster) Promiscuous social behavior Monogamous social behavior Young et al Nature

49 The genetic basis for pair bounding Vasopressin R1a? Walum et al 2008, PNAS

50 The use of mouse models to study neuropsychiatric disorders (e.g. autism spectrum disorders)

51 Kanner L. Autistic disturbances of affective contact. Nervous Child 2, (1943)

52 DSM-V: classified better the symptoms (criteria of diagnostics)

53 2014: 1 in 68 children (1 in 42 boys and 1 in 189 girls) 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)

54 American Psychiatric Association DSM-5 Development (May, 2013) 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.

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56 Stoner et al 2014 New England Journal of Medicine

57 The use of mouse models to study neuropsychiatric disorders (e.g. autism spectrum disorders)

58 Recent mouse history 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) W.E. Castle C.C. Little

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60 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)

61 Mouse sequence reveals great similarity with the human genome Extremely high conservation: 560,000 anchors Mouse-Human Comparison both genomes billion bp long > 99% of genes have homologs > 95% of genome syntenic

62 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

63 Transgenic Animals: Definition Mutant animals carrying experimentally introduced foreign genetic elements in all their cells, including the germline

64 Transgenic and Knockout Animals 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

65 Generating Transgenic Mouse Model Analyse the progeny by PCR or Southern blotting Institute of Laboratory Animal Science University of Zurich Transgenic construct: gene size Varied expression levels: random integration, copy number F 0 mice may be mosaic Lethality due to transgene integration or expression

66 Generating Knockout Mouse Model

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68 Knockout mouse model Behavioral phenotyping of the transgenic mouse model Social and reproductive, Stress-anxiety, Learning and memory, Orientation, Motor and cognition skills, sensory perception, etc

69 Voineagu et al 2010; Nature

70 Common genetic basis to Autism and Schizophrenia Schizophrenia Autism Autism & Schizophrenia McCellan & King 2010; Cell

71 Silverman et al 2010; Nature Reviews Neuroscience

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73 Silverman et al 2010; Nature Reviews Neuroscience

74 Studying autistic-related behaviors in mouse models

75 Autism Spectrum Disorders Main characteristics: Social and Communication Deficits Fixed Interests (Rigidity in habits) Stereotypic (repetitive) Behaviors Symptoms must be present in early childhood

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78 Social behavior test for mice

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80 Cognitive rigidity Wet T-maze assay

81 Stereotypic behavior

82 Suggested behavioral assays in animal models relevant to anxiety/stress disorder Cryan and Holmes, 2005

83 Examples of automated behavioral phenotyping systems for rodents to evaluate locomotion, anxiety, memory