After 22 h of abstinence, rats with a cocaine history had greater c-fos, zif268, arc, and bdnf, mRNA in the dmPFC and OFC than rats with a saline history when re-exposed to the operant chamber. c-fos (a), zif268 (b), arc (c), and bdnf (d) hybridization signals. Right, representative coronal hemi-sections illustrating the expression pattern of each gene. Left and middle: quantitative analysis of the integrated density of the hybridization signal in dmPFC (left) and OFC (middle). $p<0.05, $$p<0.01, $p<0.001 vs. Sal-NL; ^p< 0.05,^^p<0.01, ^^^p<0.001 vs. Sal-LA. ID integrated density