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Basic Mouse Neurobehavioral Exam (or how to give a mouse a physical). Julie Watson Vet MB DACLAM. Resources. Jacqueline Crawley Crawley,J and Paylor,R. Hormones & Behavior 197-211 (1997) “What’s Wrong with my Mouse?” Wiley-Liss 2000. Samuel Irwin - First Phenotyping Screen
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Basic Mouse Neurobehavioral Exam(or how to give a mouse a physical) Julie Watson Vet MB DACLAM
Resources • Jacqueline Crawley • Crawley,J and Paylor,R. Hormones & Behavior 197-211 (1997) • “What’s Wrong with my Mouse?” Wiley-Liss 2000. • Samuel Irwin - First Phenotyping Screen • Psychopharmacologia (Berl.) 13 222-257 (1968) • SHIRPA stage I • Mamm Genome. 1997 Oct;8(10):711-Rogers DC, Fisher EM, Brown SD, Peters J, Hunter AJ, Martin JE • Websites: • Eumorphia http://www.eumorphia.org/EMPReSS/servlet/EMPReSS.Frameset • MRC Mutagenesis Program • http://www.mgu.har.mrc.ac.uk/facilities/mutagenesis/mutabase/ • Clinical approach
Goals • Detect abnormalities likely to affect future behavioral tests • Blindness • Physical defects • Deafness
Age-related hearing loss & vestibular defects (<3m) Many 129 strains A/J C57BR, C57L DBA I, LP, NOD, ALR, ALS C57BL/6J @12-18m Blindness (rd1 gene) FVB C3H BUB CBA SJL SWR NON P, PL Background Strain
Goals (2) 2. Suggest further testing • Presence of abnormal behaviors • Absence of normal behaviors • Motor or neurological deficits
Pitfalls • Variations due to: • Husbandry methods (see John Crabbe, Science 1999) • Age/sex/background strain • Noise/temperature/humidity/location etc. • Time of day • Detect only sizeable deficits • Background strain not inbred. F1’s, N2’s • Are controls comparable ? • Insufficient group size • Limited statistical analysis available - ordinal data • Check genotyping reliability
WEIGHT PERTINENT INFORMATION TESTER BLINDED TO GENOTYPE
Tests • Behavior in Empty Cage: • Gait, posture, general appearance • Are normal behaviors present? • Exploring, thigmotaxis, digging, grooming, rearing • Are abnormal behaviors present? • freezing, wild running, stereotypies, seizures, pruritus
Knockout Mouse LIMITED REARING
Tests Pick up, record abnormal physical features Whisker loss Bald patches or unkempt haircoat, piloerection Eyes Legs and tail
General Reactivity • Response to approach • Body tone • Petting escape • Passivity
Postural Reactions and Reflexes • Trunk curl • Righting reflex • Forelimb proprioceptive positioning • Rearlimb withdrawal
Tests –V & VII NerveFacial sensory and motor • Whisker response • Ear twitch • Palpebral reflex (V, VII)
Sight • Placing – visual II • Placing – tactile
Tests • Clicker / hearing • Pupil / response to light • Biting / aggression
Impact of Physical Deficits on Behavioral Tests Impact of Blindness • Learning and memory tests • Water maze, contextual fear conditioning • animal cannot learn? • has limited spatial abilities? • Consider alternatives • 2 lever or hole-poke test in operant chamber • Anxiety tests • Visual cliff, elevated T maze, light- dark box • Low anxiety?
Whisker Deficits, Itchy Skin • Lack of Whiskers • Anxiety tests e.g.visual cliff, elevated T maze – • Skew response compared with mice with whiskers • ? Remove whiskers • Itchy skin (B6 dermatitis) • open field, aggression • hyperirritability, • increased activity • increased aggression
Hearing Deficits • Cued fear conditioning • Use contextual fear conditioning • Prepulse inhibition • Nb DBA still works
Examples of Further Testing • Open Field • Light Dark Box • Elevated Plus Maze • Accelerating Rotarod • Cued and Contextual Fear Conditioning • Morris Water Maze
Open Field total activity, discrete movements, distance traveled rearing
Light Dark Box • Conflict between novelty exploration and avoidance of light open spaces • Strain variations • Responsive to anxiolytics
Elevated Plus Maze • Exploration vs. aversion to open space - prefers dark enclosed arms • Score entries into arms over 5 min trial • Anxiolytics increase entries into open arms - widely used in drug discovery PICTURE CREDITS: EUROPEAN MOLECULAR BIOLOGY LABORATORY