Spatial memory following selective cholinergic lesion of the nucleus basalis magnocellularis

The aim of this study was to investigate the modulation of the cognitive function by the cholinergic cells of the nucleus basalis magnocellularis (NBM) and was designed to investigate the role of the NBM cholinergic cells in learning and memory using the immunotoxin 192 IgG-saporin to produce selective lesions of cholinergic NBM neurons. A total of 16 male outbred albino rats were used in the present study to investigate the ability of sham-operated and NBM immunotoxin lesioned rats to learn the location of a visible, as well as submerged platform in a water maze. Examination of the AChE stained sections showed that after injections of 192 IgG saporin into the NBM, animals exhibited significantly less AChE staining in PFC as compared to sections obtained from sham-operated animals. An overview of the data from both competition trials for each group show that the sham-operated rats in 13 trials out of 16 competition test trial used place strategy and NBM-lesioned ones used this strategy in 6 trials. Decreased place-bias in NBM-lesioned rats compared to the sham-operated rats was significant (t(d )= 2,42, P<0.02).The data obtained in the sham-operated and NBM-lesioned animals in the present study, demonstrate that the choice of strategy in the competition trial is related to performance during training: the rats exhibiting cue strategy (NBM-lesioned) on the competition trial had significantly worse performance during hidden platform training than those (sham-operated) exhibiting a place strategy. These findings suggest that the NBM is essential for accurate spatial learning and suggest its role in processing information about the spatial environment, but also we can propose, that the behavioral deficits described in the present study is nonmnemonic, possibly caused by deficit in attentional function.