Abstract
These experiments examined the role of GABAergic systems in modulating septohippocampal cholinergic influences on learning. Microinjections of the GABA A agonist muscimol (0.5, 1.0 or 5.0 nmol) or physiological saline were administered (0.5μl) into the medial septum of rats via chronically implanted cannulae just prior to daily training in the Morris water maze spatial learning task. The animals received 3 training trials on each of 4 days. The escape latencies of rats trained with a submerged escape platform at a fixed location were significantly shorter than those trained with a randomly located platform. Rate of learning of the fixed location was significantly impaired in rats given pretraining muscimol injections in the medial septum at doses (1.0 and 5.0 nmol) that significantly reduced hippocampal high-affinity choline uptake (HACU). Analyses of responses on a probe trial with no pretraining injections and no platform revealed that, in comparison with controls, animals that had received muscimol prior to each training session were less likely to swim in the region where the platform had been located. The finding that muscimol-injected rats were subsequently able to learn the task when trained without muscimol injections indicates that the acquisition impairment was not due to a lasting effect of the drug injections. Our results are consistent with the view that the view that septal GABAergic modulation of the septohippocampal cholinergic pathway is involved in regulating the acquisition of spatial information.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.