Comparative effects of cholinergic drugs and lesions of nucleus basalis or fimbria-fornix on delayed matching in rats.
To provide a more specific test of memory impairments following lesions to central cholinergic systems, rats were trained on an operant delayed matching task. Ibotenic acid lesions of the nucleus basalis produced a disruption of performance at all delay intervals (a parallel downward shift in the delay-performance curve). By contrast, fimbria-fornix transections had no effects at short delays, but produced a progressively greater impairment as the delays lengthened (an increased downward slope of the delay-performance curve). Scopolamine produced a dose-dependent disruption of performance, apparent at the shortest delays but greater at longer delays, that was similar to the two lesion deficits combined, whereas physostigmine induced a mild but significant enhancement of performance. The results support the hypothesis that disruption of hippocampal circuitries, including cholinergic afferents via the fimbria-fornix, produces short-term or working memory impairments, whereas disruption of the cortical cholinergic system implicates more stable long-term aspects of task performance. Peripherally administered cholinergic drugs produce both types of effect and thus may influence both systems.
D000818:Animals; D001479:Basal Ganglia / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology; D002799:Cholinergic Fibers / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000502:physiology; D008568:Memory / Q000502:physiology*; D008694:Methamphetamine / Q000494:pharmacology; D009434:Neural Pathways / Q000502:physiology; D010830:Physostigmine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012601:Scopolamine / Q000494:pharmacology; D012688:Septum Pellucidum / Q000502:physiology*; D013377:Substantia Innominata / Q000502:physiology*
D008694:Methamphetamine; D010830:Physostigmine; D012601:Scopolamine