Brewing Anxiety: Caffeine‐Induced Thigmotaxis in Zebrafish Larvae
Rishi Rai, Thais Del Rosario Hernandez, Robbert CretonABSTRACT
Background
Thigmotaxis, or edge preference, is widely used as a measure of anxiety in vertebrate model systems. However, variability in this behavior limits its utility as a scalable measure for anxiolytic drug discovery. In the current study, we examine caffeine‐induced thigmotaxis, using 5‐day‐old zebrafish larvae as a model system.
Method
We modified our imaging system and AI‐assisted analysis for measurements of behavior in six‐well plates. The imaging system was used to measure thigmotaxis and several other behaviors, including overall activity, scoot and burst swimming, and responses to acoustic and visual stimuli.
Result
Caffeine (100 mg/L) caused the zebrafish larvae to exhibit increased edge preference, decreased activity, increased scooting, and decreased bursting behavior. Coadministration with diazepam (0.25 mg/L), a central nervous system depressant, significantly reduced caffeine‐induced thigmotaxis and increased locomotor activity.
Conclusion
These findings support edge preference as a reliable measure of anxiety and reconcile existing conflicting results regarding diazepam's anxiolytic efficacy in zebrafish larvae, suggesting that anxiolytic effects are most pronounced against a heightened anxiety baseline. These findings also establish a robust platform for high‐throughput identification of anxiolytic compounds with potential relevance for treating anxiety and related stress in humans.