Fig. 1.

Selective, functional expression of ChR2-mCherry in the Locus Coeruleus. (A) Direct injection of CAV2-PRS-ChR2-mCherry efficiently transduced the LC neurons. Inset demonstrating co-localization of mCherry and DBH (1 µm confocal slice). (B) (i) Transduced LC neurons expressing ChR2-mCherry in acute pontine slices. (ii) Whole cell recording from LC neuron whose spontaneous firing is entrained by light pulses at 40 Hz (blue bar, 10 ms×10 mW, 473 nm, inset expanded). This high frequency evoked discharge is followed by a refractory period. (iii) Inward currents characteristic of ChR2 induced by light (500 ms×10 mW) at V_h −40 to −90 mV and plotted below as normalized steady state current (relative to V_h −70 mV, mean±SD, n=17). (C) Extracellular recording in vivo from a transduced LC neuron. Light pulses (473 nm; 15 mW×20 ms) entrained 1:1 neuronal firing at a frequency of 5 Hz (shown expanded on right with overlay of 10 spikes).