Figure 1.

Comparison of the opioid mRNA, opioid peptide, and neurotransmitter levels between the left and the right pgACC. Data are shown as mean ± SD of the normalized levels in the LH [L/(L + R)] and RH [R/(L + R)], where L and R are levels in the LH and RH, respectively. Dashed lines at a 0.66 value mark 2-fold differences between the hemispheres. Significance levels in ANOVAs followed by ANCOVAs when appropriate: Lateralization effects, *P < 0.05, **P < 0.01; sex effects, ##P < 0.01; lateralization × sex interactions, §P < 0.05.