STEERING FROM THE REAR: COORDINATION OF CENTRAL PATTERN GENERATORS UNDERLYING NAVIGATION BY ASCENDING INTERNEURONS

Area of Science:

• Neuroscience
• Animal Behavior
• Developmental Biology

Background:

• Coordinated animal movement is crucial for survival and goal achievement.
• Understanding neural circuits controlling locomotion and navigation is a key neuroscience challenge.

Purpose of the Study:

• To characterize the anatomy and function of ascending interneurons in Drosophila larvae.
• To investigate how these neurons influence steering, navigation, and motor control.

Main Methods:

• Electron and light microscopy for anatomical reconstruction.
• Calcium imaging to monitor neuronal activity in relation to motor neurons.
• Optogenetic manipulation to assess functional roles in isolated CNS and behaving larvae.

Main Results:

• Cholinergic 19f cells receive input from premotor interneurons and project to anterior segments.
• 19f neurons are recruited into most motor programs, with activity lagging motor neuron output.
• Optogenetic activation/inhibition of 19f cells modulated exploratory movements and forward locomotion.
• Altered 19f activity impacted olfactory navigation behavior.

Conclusions:

• Ascending interneurons monitor motor activity and shape rhythm generator interactions.
• These neurons play a context- and location-specific role in coordinating complex behaviors like navigation.
• Findings provide insights into neural mechanisms underlying movement coordination and goal-directed navigation.