Supplementary Figure 9: VARNAM expression in electroporated neurons and optical recordings in acute slices.
From: Fast, in vivo voltage imaging using a red fluorescent indicator
(a) High-resolution confocal images of VARNAM-expressing superficial layer pyramidal neurons in fixed brain slice. Vivid membrane localization with minimal intracellular aggregation was noted. (b) Concurrent optical (red) and electrical (black) recordings of high-speed AP bursts in a VARNAM-expressing neuron in acute brain slice. Bursts were triggered by current injections of 300-ms duration at increasing amplitudes (starting at 200 pA, 5 cycles, ∆100 pA). Dashed lines indicate trial shown at an expanded time scale below, overlaid with the optical trace. (c) Concurrent optical and electrical recordings of spontaneous APs in a VARNAM-expressing neuron in acute brain slice. Optical APs were observed in the soma (orange) and proximal apical dendrite (pink). Dashed box indicates time frame expanded to the right. Arrows indicate afterhyperpolarizations recapitulated in the optical trace.
