Fig 2. Prediction of synaptic polarities of the C. elegans ionotropic chemical synapse connectome.

(A) Prediction method. Connectome and gene expression data were manually curated (see Methods). Polarities of chemical synapses were predicted based on the neurotransmitter expression of presynaptic neurons and the matching receptor gene expression of the postsynaptic neurons. (B) Distribution of predicted and unpredicted synapses. We were able to predict polarity for 73% of chemical synapses (green). The polarities of the rest of synapses were unpredicted due to unknown neurotransmitter expression of the presynaptic neurons (dark grey) or non-matching receptor gene expression of the postsynaptic neurons (light grey).