when lever pressing stabilized all rats were implanted with two cannulae , one in the lateral ventricle ( lv ) and the second in one of the following brain structures : dorsal hippocampus ( dh ) , locus ceruleus ( lc ) , lateral hypothalamus ( lh ) , reticular formation ( rf ) , or the vestibular nucleus ( vn ) .
C0006104
of
C0042600
vestibular nucleus