Histology
After behavioral testing was complete, rats were euthanized with an overdose of sodium
pentobarbital (100 mg/kg, i.p.),, and 1 μl of green dye was microinjected in the same
manner as during drug injection, for later visualization of cannula placement. Rats were then
decapitated and their brains collected and frozen on dry ice. Frozen coronal brain sections
were cut at 40 μm on a cryostat and mounted for verification of correct cannula placement.
Animals with misplaced cannulae outside the MPOA were analyzed separately as described
below.