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. Author manuscript; available in PMC: 2012 Jun 8.
Published in final edited form as: Neuron. 2011 Dec 8;72(5):721–733. doi: 10.1016/j.neuron.2011.10.028

Figure 2. In vitro and in vivo physiology of optical responses in VTA DA neurons in Th::Cre rats.

Figure 2

A. Example traces from a ChR2-expressing Th::Cre neuron in response to intracellular current injections (Vm: −43mV, 50pA current steps beginning at −500pA). B. Continuous blue light (470nm) evokes large (>500pA) inward currents in ChR2-expressing Th::Cre neurons. Inset, summary graph of population data for photocurrent properties (n=7). C. Representative responses to 20 Hz optical or electrical stimulation trains in ChR2-expressing and YFP-only expressing Th::Cre neurons. Spike size and shape are comparable to those previously reported for these cells. D. Left, ChR2-expressing Th::Cre neurons are able to reliably follow light-evoked pulse trains over a range of frequencies. Right, Summary data for spike fidelity (%successful spikes in 40 light flashes) in ChR2-expressing Th::Cre neurons (n=7; in panels A–D data are from Ih/large ChR2-YFP expressing cells). Errorbars are SEM. E. Optically evoked time-locked multi-unit neural activity recorded with an optrode in vivo in the VTA of anesthetized Th::Cre+ rats injected with Cre-dependent ChR2. Top: 20 Hz, 20 pulses, 5 ms pulse duration, 473 nm. Bottom: same recording site and photostimulation parameters but longer stimulation duration (100 pulses). Horizontal blue lines represent timecourse of optical stimulation.