FIGURE 1.

Schematic representation of the experimental paradigm performed in SERT^−/− and SERT^+/+ rats. (a) The psychomotor effects of AMPH were assessed immediately after AMPH injection and evaluated for 120 min. (b) AMPH self‐administration training was performed during 10 days, after which the animals were subdivided into short‐ (ShA) or long‐access (LgA) groups. During the next 18 days the rats were allowed to self‐administer AMPH under either of these conditions. (c) Twenty‐four hours after the final ShA or LgA session, rats were decapitated, and punches from the nucleus accumbens core (cNAc) and shell (sNAc) subregions (localized using the Paxinos & Watson, 2007 edition of the rat brain atlas) were collected for gene expression analyses of the glutamatergic synapse