Discussion of imalsogreg's comment: For all the papers inferring dopamine concentrations from the spiking of a small number of VTA or SN neurons, it's very cool to see the ACTUAL dopamine readout. Comparing this with said spiking will be a really important step in bridging the literature. I hope voltametry brings some clarity to the diversity of spike patterns in neurons. Even within genetic subsets, individual neurons have very different correlates (citation needed); maybe milti-site voltametry can bring some clarity to that.