Summary
A bioRxiv preprint describes zAcademy, an open-source programmable arena for conditioning adult zebrafish. In experiments, avoidance responses differed between wild-type and shank3 knockout fish and were driven mainly by females.
Researchers have described zAcademy, an open-source programmable arena that uses controlled visual cues and mild electrical stimulation to study learning and memory in adult zebrafish. In a bioRxiv preprint, the system revealed different avoidance responses between wild-type fish and fish with the shank3 gene knocked out, as well as differences between female and male fish.
The platform combines a 3D-printed dual-chamber arena, software-controlled LED matrices below the arena, graphite-rod electrodes operated through an Arduino-controlled relay and an overhead infrared camera. The authors also released the hardware and software designs, along with a position-based workflow for analysing the fish's location.
How zAcademy tests conditioned avoidance
The experiment used classical conditioning: a visual cue was repeatedly paired with an aversive event, allowing the researchers to test whether the animals later changed their behaviour when the cue appeared by itself. In zAcademy's setup, adult zebrafish experienced a checkerboard light pattern beneath the arena as the conditioned stimulus. The pattern was paired with a mild electrical shock, the unconditioned stimulus.
Training took place in one 180-minute session. The researchers then presented the checkerboard pattern without the shock in six probes. The first probe occurred immediately after training and was used to assess learning. Five further probes occurred at 30-minute intervals to assess memory over time.
The researchers quantified spatial preference using a performance index based on occupancy of the dark zone. This provided a numerical measure of whether fish moved towards the darker area when the conditioned pattern was presented without reinforcement.
Responses differed by genotype and sex
Wild-type fish shifted towards the dark zone immediately after training. Fish with a shank3 knockout did not show the same immediate shift in the reported experiment, indicating a genotype-linked difference in the measured avoidance response.
The wild-type response was driven mainly by females rather than males. Among the fish that responded initially, females also maintained an elevated performance index across more of the later probes. The result therefore linked both the acquisition of the avoidance response and its persistence over subsequent tests to sex in this experimental setting.
The study reports behavioural differences in an animal model; it does not establish that the same pattern occurs in humans. The abstract also does not provide the numbers of fish in each experimental group or effect estimates, details that are important for judging the size and precision of the reported differences.
A configurable platform for behavioural experiments
The value of zAcademy is not limited to the particular zebrafish comparison. Its programmable LEDs, electronically controlled stimulation and automated tracking allow researchers to modify the conditioning protocol while keeping the main hardware and analysis workflow consistent. Releasing the system as open hardware and open software could make it easier for laboratories to reproduce the setup or adapt it for comparisons involving different genetic backgrounds and behavioural conditions.
The findings are reported in a bioRxiv preprint and have not yet appeared as a peer-reviewed journal article. The experiment itself used adult zebrafish, making zAcademy a tool for studying learning-related behaviour in that model rather than a direct test of human cognition.