Neural circuit mechanisms for transforming learned olfactory valences into wind-oriented movement

Area of Science:

• Neuroscience
• Animal Behavior
• Genetics

Background:

• The brain's mechanism for using memory to guide future actions remains unclear.
• In fruit flies, olfactory associative learning involves mushroom body compartments assigning stimulus valence.
• Understanding this process is key to deciphering memory-driven behaviors.

Purpose of the Study:

• To investigate how memories stored in different mushroom body compartments influence locomotion.
• To identify neural circuits that translate learned valences into specific actions.

Main Methods:

• Utilized a photoactivation screen with split-GAL4 drivers in *Drosophila*.
• Employed electron microscopy (EM) connectomics to map neural circuits.
• Recorded changes in locomotion and neural responses during memory retrieval.

Main Results:

• Identified UpWind Neurons (UpWiNs) postsynaptic to mushroom body output neurons (MBONs) that control upwind steering.
• UpWiNs integrate inputs from appetitive and aversive memory pathways.
• Blocking UpWiNs impaired appetitive memory recall and reduced upwind movement.

Conclusions:

• Learned valences are transformed into concrete actions via divergent and convergent neural networks.
• UpWind Neurons play a critical role in translating appetitive memories into directed locomotion.
• This neuronal architecture is conserved across species, suggesting broad applicability.