Box Figure I.

Representative traces illustrating some of the key electrophysiological features of dopamine neurons. (a) Examples of rat VTA dopamine neurons spontaneous firing in vivo in regular (top trace) or irregular (middle trace) patterns, including bursts (lower traces). (b) Extracellular waveforms of SNC dopamine neurons in rats recorded with two different filter settings in vivo. ((c) Inhibition of a VTA dopamine neuron by dopamine, in a mouse brain slice. Reproduced, with permission, from [25] (a), [40] (b), [55] (c) and (d). d) Hyperpolarisation-activated inward current as seen in membrane sag during hyperpolarising pulse in current-clamp recording from a VTA dopamine neuron in mouse brain slice.