Muscarinic cholinergic neuromodulation reduces proactive interference between stored odor memories during associative learning in rats.

Publisher Website
Google Scholar
Abstract
Previous electrophysiological studies and computational modeling suggest the hypothesis that cholinergic neuromodulation may reduce olfactory associative interference during learning (M. E. Hasselmo, B. P. Anderson, & J. M. Bower, 1992; M. E. Hasselmo & J. M. Bower, 1993). These results provide behavioral evidence supporting this hypothesis. A simultaneous discrimination task required learning a baseline odor pair (A+B-) and then, under the influence of scopolamine, a novel odor pair (A-C+) with an overlapping component (A) versus a novel odor pair (D+E-) with no overlapping component. As predicted by the model, rats that received scopolamine (0.50 and 0.25 mg/kg) were more impaired at acquiring overlapping than nonoverlapping odor pairs relative to their performance under normal saline or methylscopola mine. These results support the prediction that the physiological effects of acetylcholine can reduce interference between stored odor memories during associative learning. One of the major problems in understanding memory concerns how similar items are stored and retrieved so that the individual identity of the items is preserved without interference. We are specifically interested in proactive interference, which occurs when previously learned informa- tion impairs the acquisition of new, related information. A considerable body of research has implicated acetylcho- line (ACh) as an important neurotransmitter in learning and memory processes, but there is disagreement about the specific role the cholinergic system plays in learning and memory (Blokland, 1996; Hunter & Murray, 1989). A dense population of cholinergic neurons in the central nervous system can be found distributed across several nuclei in the basal forebrain, which has widespread telencephalic projec- tions including the hippocampus, olfactory bulb, and olfac- tory cortex (Renner, Dodson, & Leduc, 1992). An advantage of using odor stimuli to study memory is that the olfactory cortex is monosynaptically connected to areas implicated in memory formation, such as the hippocampus and frontal cortex (Lynch & Staubli, 1993; Slotnick & Risser, 1990; Staubli, Fraser, Faraday, & Lynch, 1987). Muscarinic cholinergic transmission, specifically, has been shown to be required for performance in an olfactory

This publication has 0 references indexed in Scilit: