Figure 1.
TERPS tool mechanism. A, B, UAS-ChR and UAS-NaChBac (NaChBac) expression are driven by a Gal4 line, in PMIN A and B). A, Light stimulation of ChR in PMIN A increases its open probability so that an inward, nonspecific cation current depolarizes the cell. This depolarization gates the voltage-sensitive NaChBac channel, which carries a strongly depolarizing sodium current. This induces synaptic transmission to neighboring aCC. B, PMIN B expresses ChR and NaChBac; however, it is not monosynaptically connected to aCC: it is polysynaptically connected to the motoneuron via PMIN C. TTX blocks the Nav channels in PMIN C, so that there is no synaptic transmission between it and aCC, following optogenetic stimulation of PMIN B.