Avoidance response to CO2 in the lateral horn.

Area of Science:

• Neuroscience
• Insect Olfaction
• Behavioral Biology

Background:

• Olfactory information in flies is relayed from the antennal lobe to the mushroom body (MB) for learning and the lateral horn (LH) for innate responses.
• The LH's role in innate olfactory behaviors is inferred but lacks direct experimental evidence.
• Understanding the neural circuits underlying innate responses is crucial for deciphering sensory processing.

Purpose of the Study:

• To directly investigate the behavioral role of lateral horn neurons (LHNs) in innate olfactory responses.
• To identify specific neural circuits involved in the fruit fly's response to carbon dioxide (CO2).
• To elucidate the functional connectivity and output pathways of LHNs.

Main Methods:

• Utilized the CO2 response in flies as a model system for innate behavior.
• Employed genetic manipulation to control the activity of specific LHNs.
• Conducted behavioral assays, calcium imaging, and electrophysiological recordings to assess neural activity and behavioral output.

Main Results:

• Demonstrated that the LH is essential for innate behavioral responses to CO2.
• Identified two distinct sets of LHNs required for the full CO2 behavioral response, showing selectivity for CO2 over other odors.
• Revealed that one set of LHNs projects to the superior intermediate protocerebrum (SIP) and also interacts with local neurons within the LH.

Conclusions:

• The lateral horn plays a direct and critical role in mediating innate responses to CO2.
• Specific LHNs are necessary and selective for processing CO2 stimuli, contributing to innate behaviors.
• The dual output of LHNs to the LH and SIP allows for potential coordination between innate (LH) and learned (MB) responses.