No abstract

The neural basis of behavior is identified by systematically manipulating the activity of specific neurons and screening for loss or gain of phenotype. Therefore, robust, high-scoring behavioral assays are necessary for determining the neural circuits of novel behaviors. We report a simple Y-maze design for Drosophila olfactory learning and memory assay. Memory scores in our Y-mazes are considerably better and longer-lasting than scores obtained with commonly used T-mazes. Our results suggest that trapping flies to an odor choice in a Y-maze could improve scores. We postulated that the improved scores could reveal previously undetectable memory traces, enabling the study of underlying neural mechanisms. Indeed, we identified unreported protein synthesis-dependent long-term memories (LTMs), reinforced by ingestion of (1) an aversive compound and (2) a sweet but nonnutritious sugar, both 24 h after training. We also used Y-mazes to probe how using a greater reward may change memory dynamics. Our findings predict that a greater sugar reward may extend existing memory traces or reinforce additional novel ones.

The neural basis of behaviour is identified by systematically disrupting the activity of specific neurons and screening for loss in phenotype. High scoring behavioural assays are thus necessary for identifying the neural circuits of novel behaviours. Here, we report the design and use of a Y-maze based classical olfactory learning and memory assay in Drosophila. Appetitive memory scores in our Y-maze are considerably greater and longer-lasting than that from a commonly used T-maze design. We show that testing in the Y-maze is key to the improved scores. We also observed considerable 24-hour aversive taste reinforced memory performance with only one training trial using Y-mazes. This allowed us to determine the protein synthesis dependence of long-lasting aversive taste memories for the first time in flies. The Y-maze assembly will make olfactory conditioning more accessible and it will allow the study of novel memory phenotypes in Drosophila.