A working memory “theory of relativity”: elasticity in temporal, spatial, and modality dimensions conserves item capacity in radial maze, verbal tasks, and other cognition

Using different types of stimuli, such as pictures, horizontally written Japanese words, and vertically written Japanese words, this study investigated the spatial patterns of the sense of familiarity within the visual field. The perceptual asymmetry theory predicted that stimuli in the lower visual field would be processed more fluently and would therefore be perceived as more familiar. The working memory theory, originally proposed in space–number research, envisaged type-specific spatial patterns for different stimuli. Participants made old/new recognition memory judgements for stimuli, presented at random positions, while their eye movements were recorded. The observed spatial patterns changed according to the stimulus type (e.g., “more left = older” for horizontally written words and “upper = older” for vertically written words), and this flexibility is encapsulated by the working memory theory as follows: (a) stimulus-type-specific spatial configurations are encoded in long-term memory on the basis of one’s experience (e.g., vertically written words are empirically associated with the “upper = older” spatial configuration), (b) the presentation of a stimulus automatically cues the temporal activation of the associated spatial configuration in working memory, and (c) the referential process between the stimulus and configuration unconsciously affects the viewer’s sense of familiarity.

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

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y86-061 ◽

1986 ◽

Vol 64 (3) ◽

pp. 376-382 ◽

Cited By ~ 35

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.

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