Title
Linear and nonlinear prefrontal and parietal activity during multiple-item working memory.
Abstract
Most parts of the prefrontal and posterior parietal cortices show sustained activity during short-term maintenance of visual information and their activity increases with increasing memory set size. To investigate the interplay of feature selectivity, memory load and inter-item interaction (or interference) on sustained activity, we compared and contrasted fMRI signal during the retention of two items from the same or different visual feature categories (e.g., two line orientations versus a line and a color) relative to the retention of single items. Data from 16 young adults revealed three types of activation patterns in the prefrontal and posterior parietal cortices. First, among the prefrontal and posterior parietal areas that showed preferential responses to line orientations, some exhibited linear increases in sustained activity whereas others exhibited nonlinear increases in correspondence to the number of lines in the memory set. Second, the right lateral prefrontal and ventral posterior parietal areas, albeit not showing differential sustained activity relative to lines or colors, were disproportionately more active during holding two lines in comparison to holding a line and a color. Third, the left posterior intraparietal sulcus showed a weak effect of memory set size regardless of the items' visual features. These observations suggest that rather than number of items, a combination of factors such as visual feature and memory-set homogeneity may have the greater influence on prefrontal and parietal activity during multiple-item working memory. This is consistent with the view that working memory capacity is influenced by the level of interaction or interference between visual stimuli, which is stronger between items from the same feature category.
Year
DOI
Venue
2011
10.1016/j.neuroimage.2011.05.002
NeuroImage
Keywords
Field
DocType
Multiple item working memory,Posterior parietal cortex,Prefrontal cortex,fMRI
Consumer neuroscience,Developmental psychology,Prefrontal cortex,Working memory,Psychology,Visual memory,Cognitive psychology,Posterior parietal cortex,Interference theory,Spatial memory,Intraparietal sulcus
Journal
Volume
Issue
ISSN
57
3
1053-8119
Citations 
PageRank 
References 
1
0.40
8
Authors
2
Name
Order
Citations
PageRank
Yuji Yi1111.39
Hoi-Chung Leung2466.69