Fig. 1: Sequential place preference using phasic VTA DA photostimulation interrogates DA roles in reinforcement and motivation.
From: Dopamine builds and reveals reward-associated latent behavioral attractors
a Left, double-floxed inverted open-reading frame (DIO) channelrhodopsin 2 - yellow fluorescent protein (ChR2-YFP)-expressing adeno-associated virus (AAV5) was injected in ventral tegmental area (VTA) from dopamine transporter (DAT)-Cre mice, resulting in selective expression of ChR2-YFP in tyrosine hydroxylase (TH)-expressing dopamine (DA) neurons. IPN: interpeduncular nucleus, ml : medial lemniscus. Right, VTA photostimulation was delivered when mice were detected within one of three explicit locations (A, B, C) in the open field. Mice could not receive two consecutive photostimulations at the same location (e.g. C), so they alternated between locations (e.g. A or B after C). b Top, trajectories (10 min) of one mouse expressing ChR2 in the VTA (purple) at the beginning (left) and at the end (right) of the learning sessions. Bottom, number of photostimulations against session number for Chr2-expressing (purple) and YFP-expressing (black) animals. Two-way ANOVA with repeated measures, groups: F(1) = 30.04, p = 3.10−5, time: F(9) = 5.69, p = 7.10−7, interaction: F(1,9)=3.9, p = 2.10−4. c Distance between two consecutive reward locations (top, two-way ANOVA with repeated measures, groups: F(1)=50.53, p = 1.10−6, time: F(9)=7.23, p = 8.10-9, interaction: F(1,9)=5.43, p = 2.10−6) and maximal speed (bottom, two-way ANOVA with repeated measures, groups: F(1)=71.65, p = 1.10−7, time: F(9)=8.84, p = 8.10−11, interaction: F(1,9)=2.18, p = 0.03) against session number for Chr2-expressing (purple) and YFP-expressing (black) animals. Data are presented as mean ± s.e.m. See also source data file.
