Figure 5
Combined treatments that enhance dopaminergic signaling and histone deacetylase inhibition are necessary to rescue impaired fear extinction in an enduring and context-independent manner. (a) Scheme illustrating experimental paradigm. Cond., ‘normal’ fear conditioning; Ext., fear extinction; ER, extinction retrieval, SR, spontaneous recovery; RN, fear renewal. (b) During extinction training and compared with VEH/VEH control group, reduced freezing was observed in L-dopa/VEH-treated mice during extinction trial blocks 9–10, 11–12 and 15–16 and in L-dopa/MS-275 during extinction trial blocks 9–10 through to 15–16. During ER reduced freezing was observed in L-dopa/VEH and L-dopa/MS-275 compared with VEH/VEH. L-dopa/MS-275-treated mice exhibited lower freezing compared with VEH/VEH during SR and VEH/VEH and L-dopa/VEH during RN. * VEH/VEH versus L-dopa/VEH, # VEH/VEH versus L-dopa/MS-275, §P<0.05 post hoc testing L-dopa/VEH versus L-dopa/MS-275. n=8–10 per group.
