Extended Data Figure 3: Light and electrical stimulation in the same cell elicit identical postsynaptic currents.

a, Paired whole-cell recordings of ChetaTC-expressing (YFP) and non-expressing neurons that were co-cultured on small microislands of astrocytes. Action potentials were triggered every 10 s in the ChetaTC-positive cell by alternating between 10 ms current injection via the patch pipette and 10 ms light flashes. b, Example of a cell pair with a GABAergic ChetaTC-positive neuron. Presynaptic action potentials were recorded in current clamp (CC) of the ChetaTC-positive cell. Postsynaptic inhibitory postsynaptic currents (IPSCs) were recorded in voltage clamp (VC) from the non-infected neuron (bottom panel; holding potential −50 mV). c, Presynaptic action potentials and excitatory postsynaptic currents (EPSCs) evoked by light or somatic depolarization in a pair of neurons with a glutamatergic ChetaTC-positive neuron. The postsynaptic cell was voltage-clamped at −70 mV. d, Time plot of postsynaptic responses triggered by alternating light-induced depolarization (blue bars/open symbols) and electrical stimulation (current step/closed symbols). Both EPSC and IPSC amplitudes were normalized to the first response evoked by electrical stimulation and pooled (n = 9). e, Scatter plot of postsynaptic currents evoked by ChetaTC stimulation normalized to direct electrical stimulation in the same neuron. Reponses are not different for the two modes of action potential induction (P = 0.77, one sample t-test). Error bars, s.e.m.