Synergistic Coding of Human Odorants in the Mosquito Brain

The yellow fever mosquito Aedes aegypti employs olfaction to locate humans. We applied CRISPR-Cas9 genome engineering and neural activity mapping to define the molecular and cellular logic of how the mosquito brain is wired to detect human odorants. We determined that the breath volatile carbon dioxide (CO2) is detected by the largest unit of olfactory coding in the primary olfactory processing center of the mosquito brain, the antennal lobe. Synergistically, CO2 detection gates synaptic transmission from defined populations of olfactory sensory neurons, innervating unique antennal lobe regions tuned to the human sweat odorant L-(+)-lactic acid. Our data suggests that simultaneous detection of signature human volatiles rapidly disinhibits a multimodal olfactory network for hunting humans in the mosquito brain.