Contextual Fear Learning and Memory in Alternative Stress

Contextual Fear Learning and Memory in Alternative Stress Coping Styles Matthew R. Baker and Ryan Y. Wong Department of Biology, University of Nebraska at Omaha • Animals frequently must overcome stressors • Failure to cope with stress can result in death or mental health disorders in humans • Two distinct stress coping styles 1 Stress coping Style Proactive Reactive Exploration of Novelty High Low Aggression/Dominance High Low Physiological Stress Response Low High CONTROLS: • No initial bias between conditioned and neutral context • Proactive and reactive fish display similar fear response to alarm substance • Fish exposed to distilled water did not display fear response FEAR MEMORY ACQUISITION: • • trial*treatment interaction (F 3, 165 = 71. 31 p <. 001) - treatment fish increased freezing across trials http: //www. noldus. com/animal-behavior-research/ Objectives 1. Are differences in cognitive traits related to stress coping styles? 2. Learning/memory differences between proactive and reactive individuals? Danio rerio: An emerging translational Comparative anatomy and physiology to humans http: //www. fishpain. com/fish-and-pain-brainstructures. htm http: //zebrafishart. blogspot. com/ Trial Gray Bars = Neutral Context Colored Bars = Conditioned Context Fully sequenced and easily manipulated genome Context*treatment interaction (F 1, 55 = 49. 45 p <. 001) - Treatment fish discriminate between contexts - Control fish show no bias between contexts Gray Bars = Neutral Context Colored Bars = Conditioned Context*treatment interaction (F 1, 55 = 8. 03 p =. 006) - Treatment fish discriminate between contexts - Control fish show no bias between contexts http: //xmaslectures. imascientist. org. uk/profile/rachaelinglis/ https: //speakingofresearch. com/tag/zebrafish/ Day 1: Acclimation to behavioral chamber in conditioned and neutral contexts for 15 minutes Day 3: Recall in conditioned and neutral contexts for 15 minutes Day 7: Repeat day 3 recall testing 5 Minutes • Strain*treatment interaction (F 1, 55 = 4. 13 p =. 047) - larger strain differences in treatment group 5 Minutes • Reactive fish freeze higher in conditioned context relative to proactive fish (t(46) = 3. 62 p =. 001 • Freezing behavior as indicator of fear response (remaining motionless) • Reactive fish show stronger fear memory • Trials recorded analyzed in Noldus Ethovision software (Wulliman et al. , 1996) 5 Minutes - Each fish underwent 4 training trials - Conditioned fear measures learning rate DATA ANALYSIS: FUTURE DIRECTIONS • Data analyzed using three-way repeated measures analysis of variance models in SPSS • Investigate the neuromolecular mechanisms • Strain, sex, and treatment group as between subjects factors • Neural plasticity related genes are upregulated at baseline in reactive fish 4 • Do baseline levels of these genes bias cognitive abilities? • Are higher expression of neural plasticity-related genes associated with learning/memory differences presented here? • Hippocampus (Dl), amygdala (Dm), and striatum (Vd) are three brain regions of interest 7 Summary Transparent/rapidly developing embryos Recall Day 2: Four training trials in conditioned context https: //phys. org/news/2015 -06 -role-zebrafish-largerscale-gene. html High space and cost efficiency PROTOCOL: • Both strains recall fear memory equally model 5 High throughput behavioral assays Training FEAR MEMORY RECALL 24 HOURS: • • https: //www. cam. ac. uk/research/ • Based on Pavlov’s classic associative learning experiment: FEAR MEMORY RECALL 96 HOURS: Antipredatory behavior http: //slideplayer. com/slide/8002495/ Unconditioned Stimulus: Alarm substance • Here, we use selectively bred lines of proactive and reactive zebrafish to examine learning and memory differences Exploration of novelty • Olfactory cue released from skin of injured fish Conditioned Stimulus: Context (Color) • The role of stress in learning/memory has been well characterized, however we are only beginning to discover how learning/memory capabilities are influenced by an individual’s stress coping style Latency to feed • Robust fear response to chemical alarm signal 6 trial*treatment*strain interaction (F 3, 165 = 3. 52 p =. 016 - strains may increase freezing at different rates • Stress coping styles thought to differ in behavioral flexibility and ability to incorporate new information • These selectively bred lines of zebrafish have been shown to have distinct 3, 4: ALARM SUBSTANCE: CONTEXTUAL FEAR CONDITIONING 7: • Reactive fish showed higher freezing at: - Trial 2, t(46) = 3. 29 p =. 002 - Trial 3, t(46) = 1. 97 p =. 055 • Cognitive traits may also differ 2 Genetic Backgrounds Methods Results Introduction • Context or training trial as within subjects factors References 1) 2) 3) 4) 5) 6) 7) Overli O, et al. (2007). Neurosci and Biobehav Reviews 31(3): 396 -412. Sih & Del Guidice (2012). Phil Trans Soc B 367: 2762 -2772. Wong RY, et al. (2012). Behaviour 149: 1205 -1240. Wong RY, et al. (2015). BMC Genomics 16(1): 425. Li K, et al. (2016). Cell 167: 60 -72. Speedie & Gerlai (2008). Behav Brain Res 188(1): 168 -177. Maren (2001). Ann Rev in Neurosci 24: 897 -931 • Cognitive traits such as learning/memory are closely linked to stress coping styles • Reactive fish acquired the fear memory at a faster rate • Proactive and reactive fish display equal fear memory retention 24 h post training • Reactive fish display stronger fear memory recall 96 h post training Acknowledgements We thank Danny Revers, Sandra Roundtree, and Amber Parks for zebrafish husbandry. Additionally we thank all of the Wong lab members for helpful comments and feedback. This research was supported by Graduate Research and Creative Activities grant and Biology Department research funds to MRB and UNO Start-up funds to RYW.