Intraocular Injection of Muscimol Induces Illusory Motion Reversal in Goldfish

Intraocular Injection of Muscimol Induces Illusory Motion Reversal in Goldfish

Induced activation of the gamma-aminobutyric acid_A (GABA_A) receptor in the retina of goldfish caused the fish to rotate in the opposite direction to that of the spinning pattern during an optomotor response (OMR) measurement. Muscimol, a GABA_A receptor agonist, modified OMR in a concentration- dependent manner. The GABA_B receptor agonist baclofen and GABA_C receptor agonist CACA did not affect OMR. The observed modifications in OMR included decreased anterograde rotation (0.01∼0.03</SUB>ՌM), coexistence of retrograde rotation and decreased anterograde rotation (0.1∼30ՌM) and only retrograde rotation (100ՌM∼1 mM). In contrast, the GABA_A receptor antagonist bicuculline blocked muscimol- induced retrograde rotation. Based on these results, we inferred that the coding inducing retrograde movement of the goldfish retina is essentially associated with the GABA_A receptor-related visual pathway. Furthermore, from our novel approach using observations of goldfish behavior the induced discrete snapshot duration was approximately 573 ms when the fish were under the influence of muscimol.