Serotonergic Modulation of Aggression in Drosophila Involves GABAergic and Cholinergic Opposing Pathways.

Area of Science:

• Neuroscience
• Behavioral Genetics
• Insect Models

Background:

• Pathological aggression is linked to neurological and psychiatric disorders, imposing societal costs.
• Serotonin (5HT) is a key regulator of aggression across species.
• Drosophila aggression is modulated by specific serotonergic neurons.

Purpose of the Study:

• Identify downstream targets of serotonergic neurons controlling aggression escalation in Drosophila.
• Elucidate the neural circuitry and neurotransmitter interactions involved in aggression regulation.

Main Methods:

• Optogenetic manipulation of neuron activity.
• RNA sequencing (RNA-seq) for neurotransmitter identification.
• Genetic manipulation (knockdown) to assess receptor function.

Main Results:

• Two neuron types with opposing roles in aggression control were identified, converging on the LC12 optic glomerulus.
• An excitatory cholinergic neuron type was characterized, expressing 5HT1A, sNPFR, and RDL GABA receptors.
• Knockdown of RDL receptors in cholinergic neurons increased aggression, suggesting GABAergic-cholinergic crosstalk.

Conclusions:

• Serotonin, GABA, acetylcholine (ACh), and short neuropeptide F interact within the LC12 optic glomerulus.
• Parallel cholinergic and GABAergic pathways from this sensory area fine-tune aggression regulation.
• This study reveals a complex neural network for controlling aggressive behavior in Drosophila.