Figure 1: Circumventing neural damage in a C. elegans circuit for chemotaxis. (A) Simplified circuit diagram illustrates information flow in the circuit. The AWC chemosensory neurons respond to changes in ambient odor levels and transmit information in an AWC→AIA→AIB pathway as well as a direct AWC→AIB pathway. The AIA and AIB neurons participate in regulating locomotion. (B) Removal of the AIA neurons interrupts proper information flow in the circuit, and diminishes odor-guided navigation (not shown). To circumvent this damage, we reinforced the AWC→AIB pathway by genetically inserting a new electrical synapse between AWC and AIB. This led to behavioral recovery (not shown). (C) AWC-AIB synaptic insertion led also to the inadvertent formation of new synaptic connections between the two AWC neurons themselves (as well as between the two AIB neurons). We found that this synthetic electrical coupling in itself helped restore circuit function, due to the amplification of weakened signals in the damaged circuit. AIA, AIB and AWC are names of C. elegans neurons.