Effect of nucleus basalis magnocellularis cholinergic lesions on fear-like and anxiety-like behavior.

Previous research has suggested that cholinergic neurons in the nucleus basalis magnocellularis and substantia innominata (NBM/SI) may be important in mediating aversive states. The authors investigated the effect of NBM/SI cholinergic lesions, induced with 192 IgG saporin, on behavioral measures of aversive states in rats. Behavior in the elevated plus maze and behavioral suppression induced by 2 fear-conditioned stimuli, a tone and a light, were evaluated. Lesions had no effect on any measures in the elevated plus maze but attenuated operant suppression induced by the light and attenuated freezing induced by the tone, though this last effect was not statistically significant. The results of the study suggest that NBM/SI cholinergic neurons may be important in mediating selective aspects of aversive states.