Paper Info
Title
Separating relational from item load effects in paired recognition: temporoparietal and middle frontal gyral activity with increased associates, but not items during encoding and retention.
Abstract
Working memory is affected by items stored and the relations between them. However, separating these factors has been difficult, because increased items usually accompany increased associations/relations. Hence, some have argued, relational effects are reducible to item effects. We overcome this problem by manipulating index length: the fewest number of item positions at which there is a unique item, or tuple of items (if length >1), for every instance in the relational (memory) set. Longer indexes imply greater similarity (number of shared items) between instances and higher load on encoding processes. Subjects were given lists of study pairs and asked to make a recognition judgement. The number of unique items and index length in the three list conditions were: (1) AB, CD: four/one; (2) AB, CD, EF: six/one; and (3) AB, AD, CB: four/two, respectively. Japanese letters were used in Experiments 1 (kanji—ideograms) and 2 (hiragana—phonograms); numbers in Experiment 3; and shapes generated from Fourier descriptors in Experiment 4. Across all materials, right dominant temporoparietal and middle frontal gyral activity was found with increased index length, but not items during study. In Experiment 5, a longer delay was used to isolate retention effects in the absence of visual stimuli. Increased left hemispheric activity was observed in the precuneus, middle frontal gyrus, and superior temporal gyrus with increased index length for the delay period. These results show that relational load is not reducible to item load.
Year
DOI
Venue
2002
10.1006/nimg.2002.1190
NeuroImage
Keywords
DocType
Volume
paired recognition,inferior parietal lobule,middle frontal gyrus,association,relation,complexity,chunking,Fourier descriptor,kanji
Journal
17
Issue
ISSN
Citations 
2
1053-8119
3
PageRank 
References 
Authors
0.61
2
2
Name
Order
Citations
PageRank
Steven Phillips1245.52
Kazuhisa Niki2103.40