Sexual dimorphism in the complete Drosophila male central nervous system connectome.

Complete Drosophila male CNS connectome reveals 138 dimorphic neuron types, highlighting sex-specific neural circuit differences at synaptic resolution.

• Why it matters: Understanding how sex differences in behavior are encoded in neural circuits is crucial for insights into biological sex dimorphism and its influence on behavior. The organization of dimorphic neurons within the entire nervous system has remained unclear, limiting comprehension of their functional roles.
• What they did: The authors constructed a fully annotated connectome of 166,700 neurons in the male Drosophila CNS, identifying fruitless/doublesex expression and classifying neuron types, then compared it with the female connectome at synaptic detail.
• The result: They found that most neurons are isomorphic between sexes, but 138 are dimorphic, with male-specific connections forming organized hotspots in higher brain centers, enabling detailed analysis of sex-specific neural circuitry.