Nucleus basalis magnocellularis and memory: differential effects of two neurotoxins.
Although the cholinergic system is involved in memory, noncholinergic systems may also contribute to memory. Lesions of the nucleus basalis magnocellularis (NBM) produce behavioral impairments and reduction of cholinergic markers in the frontal cortex (FC). The present study compared the behavioral effects of lesions made with two different neurotoxins, ibotenic (IBO) acid and quisqualic (QUIS) acid. IBO or QUIS was injected into the NBM, and rats were tested in three different tasks: cued delayed nonmatch-to-sample (CDNMS), spatial delayed nonmatch-to-sample (SDNMS), and spatial two-choice simultaneous discrimination (STCSD). IBO producted a greater behavioral impairment than QUIS in the CDNMS and the SDNMS, although QUIS produced a greater drop in choline acetyltransferase (ChAT) activity in the cortex than IBO. At the end of behavioral testing, IBO rats, but not QUIS rats, were impaired in the retention of both tasks. The fact that QUIS lesions produced a greater loss of NBM cholinergic neurons, as determined by decreased ChAT activity, but less of a behavioral impairment in both a spatial and nonspatial task, suggests that the loss of noncholinergic NBM neurons must contribute to the memory impairments following NBM cell loss.
Department of Psychology, Johns Hopkins University, Baltimore, Maryland 21218.
A L
AL
Markowska
G L
GL
Wenk
D S
DS
Olton
D000818:Animals; D001479:Basal Ganglia / Q000187:drug effects*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000187:drug effects*; D002799:Cholinergic Fibers / Q000187:drug effects*; D003292:Convulsants; D003463:Cues; D004193:Discrimination Learning / Q000187:drug effects*; D007051:Ibotenic Acid / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*; D009042:Motivation; D009434:Neural Pathways / Q000187:drug effects; D009949:Orientation / Q000187:drug effects; D010069:Oxadiazoles / Q000494:pharmacology*; D010080:Oxazoles / Q000494:pharmacology*; D016318:Quisqualic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D012153:Retention, Psychology / Q000187:drug effects*
D003292:Convulsants; D010069:Oxadiazoles; D010080:Oxazoles; D007051:Ibotenic Acid; D016318:Quisqualic Acid