Assessment of Replicability and Efforts to Refine an Operant Conditioning Procedure for Larval Zebrafish

Zebrafish have emerged as prominent model organisms in neurobiological research. Although most studies are performed on embryonic and larval stages within the first week post-hatching, tools for assessing cognitive functions during these early developmental stages remain limited. An appetitive conditioning paradigm has been recently developed that demonstrates discrimination learning within days of hatching and holds promise for the assessment of perception, memory, and executive functions. Despite its potential, the utility of this paradigm is hindered by certain limitations and confounding factors that may undermine its replicability. To address these concerns, we conducted a replication of the experiment in a separate laboratory, which revealed partial replicability and confirmed the drawbacks identified in the original study. Subsequently, we explored two modifications to the procedure in an effort to overcome these limitations. While both experiments demonstrated significant stimulus–response associations, the outcomes were unsatisfactory as performance in both cases fell well below that of the original procedure.