Figure 3.

Optogenetic activation of striatopallidal adenosine A_2A receptor (A_2AR) signaling in the dorsolateral striatum (DLS) exerts relatively limited and possibly opposite control over habitual action compared with the optoA_2AR in the dorsomedial striatum (DMS). (a) Left: Schematic illustration of the sites of optical fibers implantation. Right: A representative image of mCherry-optoA_2AR expression and fiber implantation. (b) Mice were under continuous reinforcement (CRF) training followed by RI30 and then RI60 training with or without optoA_2AR stimulation as described in the Materials and Methods section. The performances of optoA_2AR mice with ‘time-locked' stimulation (n=13) or with ‘light off' (n=10) during the acquisition phase were indistinguishable (repeated-measures analysis of variance (ANOVA), random interval (RI) training course × optogenetic stimulation interaction: F_5,105=0.916, p>0.05; optoA_2AR stimulation main effect: F_1,21=0.156, p>0.05). (c) OptoA_2AR mice with ‘time-locked' stimulation or ‘light off' during the RI training sessions were subjected to devaluation test as described in the Materials and Methods section. Repeated-measures ANOVA analyses revealed that there was no normalized devaluation × optogenetic stimulation interaction effect (F_1,21=0.022, p=0.884). However, preplanned t-test analysis revealed that optoA_2AR mice receiving ‘time-locked' stimulation tended to perform goal-directed behavior (only for the normalized devaluation test: t_1,12=3.725, **p<0.01; but not for devaluation test: t_1,12=2.030, p>0.05; Supplementary Figure 2c). Whereas optoA_2AR mice with ‘light off' displayed habitual behavior (normalized devaluation test: t_1,9=1.270, p>0.05; devaluation test: t_1,9=1.868, p>0.05; Supplementary Figure 2c). Data are presented as the mean±SEM. The color reproduction of this figure is available on the Neuropsychopharmacology journal online.