English: Tuning of appetitive and defensive reactions in the nucleus accumbens shell.

(Above) AMPA blockade requires D1 function in order to produce motivated behaviors, regardless of valence, and D2 function to produce defensive behaviors. GABA agonism, on the other hand, does not requires dopamine receptor function.

(Below)The expansion of the anatomical regions that produce defensive behaviors under stress, and appetitive behaviors in the home environment produced by AMPA antagonism. This flexibility is less evident with GABA agonism.