Effects of altered cholinergic function on working and reference memory in the rat

1986 ◽  
Vol 64 (3) ◽  
pp. 376-382 ◽  
Author(s):  
Richard J. Beninger ◽  
B. A. Wirsching ◽  
Khem Jhamandas ◽  
Roland J. Boegman ◽  
Sherif R. El-Defrawy
Keyword(s):  
Working Memory ◽  
Choline Acetyltransferase ◽  
Radial Maze ◽  
Cholinergic Neurons ◽  
Reference Memory ◽  
Nucleus Basalis ◽  
Nucleus Basalis Magnocellularis ◽  
Memory Errors ◽  
Biochemical Assays ◽  
Alternation Task

Many data suggest that the brain's cholinergic neurons participate in the control of memory and it has been suggested that cholinergic systems are involved differentially in working and reference memory. To test this hypothesis the effects on memory of unilateral injections of the neurotoxins, quinolinic acid or kainic acid into the cortically projecting cholinergic cells of the nucleus basalis magnocellularis (nbm) were evaluated. In experiment 1, quinolinate-injected (n = 7) and sham-operated (n = 7) rats were tested in a T-maze alternation task that requires working memory. Lesion rats performed significantly more poorly than shams and subsequent biochemical assays of cortical choline acetyltransferase (CAT) activity revealed significant reductions in the lesion rats. In experiment 2, kainate-injected (n = 9) and sham-operated (n = 8) rats were trained in an eight-arm radial maze with only four arms baited. Lesion rats made significantly more working memory errors (entries into baited arms from which the food had already been collected) than reference memory errors (entries into never baited arms). CAT assays showed that the lesion led to a decrease in cortical CAT with no significant change in hippocampal CAT. The results of these studies support the hypothesis that cholinergic neurons of the basocortical system may be differentially involved in working and reference memory.

Working Memory and Reference Memory in Adult Rats following Limbic Seizures Induced at 21 or 90 Days of Age

2002 ◽  
Vol 91 (3) ◽  
pp. 729-730 ◽  
Author(s):  
S. E. Kinoshameg ◽  
M. A. Persinger
Keyword(s):  
Working Memory ◽  
Radial Maze ◽  
Short Term Memory ◽  
Reference Memory ◽  
Memory Errors ◽  
Brain Organization ◽  
Adult Rats ◽  
Limbic Seizures ◽  
Systemic Injection

Rats were either seized or not seized at 21 days of age (weaning) or at 90 days of age with a single systemic injection of lithium (3 mEq/kg) and pilocarpine (30 mg/kg). When tested as adults (120 days of age) for spatial memory in the Olton radial maze, the rats that had been seized as adults exhibited about five times more working (short-term) memory errors than the other three groups which did not differ significantly from one another. The numbers of errors for long-term (reference) memory did not differ significantly among the four groups. The deficits in working memory for the group seized as weanlings and reported previously were not replicated. One possible explanation for this discrepancy might be differential effects upon brain organization associated with seizures evoked by injecting the pilocarpine 24 hr. rather than 4 hr. after the lithium.

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