Total epibatidine binding (Fmol/mg) in the frontal cortex (a), orbitofrontal cortex (b), outer cortex (c), inner cortex (d) in control and nicotine-exposed mice, following ethanol consumption in the DID protocol. Autoradiographic images of anterior-coronal mouse hemisections between (e) 1.70 mm Bregma and -1.58 mm Bregma, (f) -1.94 mm Bregma and -4.16 mm Bregma.