Reward taste conditioning in Drosophila melanogaster

Area of Science:

• Neuroscience
• Behavioral Science
• Sensory Science

Background:

• Appetitive taste behavior, crucial for survival, can be modified by experience.
• Previous work demonstrated suppression of appetitive taste by pairing with aversive stimuli.
• A need exists for robust assays to study the formation of appetitive taste memories.

Purpose of the Study:

• To develop and optimize a Reward Taste Conditioning (RTC) assay for studying appetitive taste memory.
• To characterize the optimal conditions for robust and reliable taste memory formation.
• To investigate the genetic and neural underpinnings of reward-based taste learning.

Main Methods:

• Tested various neutral or appetitive substances as conditioned stimuli (CS) paired with rewarding reinforcements (unconditioned stimulus, US).
• Optimized conditions using fructose (CS) and sucrose (US) for the RTC assay.
• Assessed memory formation, extinction, and duration, and investigated genetic requirements and neural circuits.

Main Results:

• Tight forward pairing of CS and US is essential for memory formation.
• Repeated unpaired presentation of the CS leads to memory extinction.
• Appetitive taste memory is sustained for at least 60 minutes and requires genes for short-term memory and intact mushroom bodies.

Conclusions:

• The developed RTC assay is a fast and reliable tool for studying reward taste learning.
• This assay facilitates investigation into genes, neuronal subtypes, and circuits involved in appetitive taste memory.
• The assay's similarity to aversive taste assays allows for comparative studies of memories with opposite valence.