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Alzheimer's disease currently afflicts approximately 4 million people in the United States, with 100,000 new cases being reported each year. As post mortem examination of AD patientsI brains has revealed a significant decrease in the number of cholinergic neurons, one approach we have taken is to look at the correlation between the depletion of certain cholinergic markers in animals and the resulting behavioral deficits. Two regions of specific interest are the medial septal area (MSA) and the nucleus basalis magnocellularis (NBM). These regions are important because they are the major source of cholinergic neurons in the brain, they are selectively targeted during aging and AD, and there have been many reports of their importance in learning and memory tasks. Therefore in this study we examined the effects on spatial learning, as assessed by the Morris water maze (MWM), in the male rat following intracerebral injections of the selective cholinergic neurotoxin, saporin-IgG. The results of this study indicate that saporin injections into the NBM impaired the performance in the MWM when compared to controls and injections of saporin into the MSA. This was revealed by significantly longer latencies to find a submerged platform and longer latencies during the spatial discrimination test.


Biology | Neuroscience and Neurobiology | Psychology