Local delivery of SCH23390 (1.5mM in saline per side, Sigma; D1/5 dopamine receptor antagonist) was used to prevent long-term memory consolidation at indicated brain areas bilaterally.
Ablation of dopamine neurons projecting to TS bilaterally was done as previously described (Menegas et al., 2018) (link). Briefly, a solution of 28.5 mg desipramine (Sigma-Aldrich, D3900-1G), 6.2 mg pargyline (Sigma-Aldrich, P8013-500MG), 10 mL water, and NaOH to pH 7.4 was prepared and injected i.p. to animals at 10 mg/kg. This solution prevents dopamine uptake in noradrenaline neurons, and increases the selectivity of uptake by dopamine neurons. Next, a solution of 10 mg/mL 6-hydroxydopamine (6-OHDA; Sigma-Aldrich, H116-5MG) in 0.2% ascorbic acid (Sigma-Aldrich, PHR1008-2G) in saline (0.9% NaCl; Sigma-Aldrich, PHR1008-2G) was injected bilaterally during stereotactic surgeries as described above into TS. The saline solution included a small amount of ascorbic acid to prevent 6-OHDA from breaking down. To further protect 6-OHDA from breaking down, this solution was kept on ice, wrapped in aluminum foil, and used within 3 h of mixing. If the solution turned brown, it was discarded, as this indicates that the 6-OHDA had broken down.
Ablation of dopamine neurons projecting to TS bilaterally was done as previously described (Menegas et al., 2018) (link). Briefly, a solution of 28.5 mg desipramine (Sigma-Aldrich, D3900-1G), 6.2 mg pargyline (Sigma-Aldrich, P8013-500MG), 10 mL water, and NaOH to pH 7.4 was prepared and injected i.p. to animals at 10 mg/kg. This solution prevents dopamine uptake in noradrenaline neurons, and increases the selectivity of uptake by dopamine neurons. Next, a solution of 10 mg/mL 6-hydroxydopamine (6-OHDA; Sigma-Aldrich, H116-5MG) in 0.2% ascorbic acid (Sigma-Aldrich, PHR1008-2G) in saline (0.9% NaCl; Sigma-Aldrich, PHR1008-2G) was injected bilaterally during stereotactic surgeries as described above into TS. The saline solution included a small amount of ascorbic acid to prevent 6-OHDA from breaking down. To further protect 6-OHDA from breaking down, this solution was kept on ice, wrapped in aluminum foil, and used within 3 h of mixing. If the solution turned brown, it was discarded, as this indicates that the 6-OHDA had broken down.