Dynamic cortical networks of verbal and spatial working memory: Effects of memory load and task practice

被引:202
作者
McEvoy, LK
Smith, ME
Gevins, A
机构
[1] EEG Syst Lab, San Francisco, CA 94105 USA
[2] SAM Technol, San Francisco, CA 94105 USA
关键词
D O I
10.1093/cercor/8.7.563
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Working memory (WM), the ability to briefly retain and manipulate information in mind, is central to intelligent behavior. Here we take advantage of the high temporal resolution of electrophysiological measures to obtain a millisecond timescale view of the activity induced in distributed cortical networks by tasks that impose significant WM demands. We examined how these networks are affected by the type and amount of information to be remembered, and by the amount of task practice. Evoked potentials (EPs) were obtained from eight subjects performing spatial and verbal versions of a visual n-back WM task (n = i, 2, 3) on each of three testing days. In well-trained subjects, WM tasks elicited transient responses reflecting different subcomponents of task processing, including transient (lasting 0.02-0.3 s) task-sensitive and load-sensitive EPs, as well as sustained responses (lasting 1-1.5 s), including the prestimulus Contingent Negative Variation (CNV), and post-stimulus frontal and parietal Slow Waves. The transient responses, with the exception of the P300, differed between the verbal and spatial task versions, and between trials with different response requirements. The P300 and the Slow Waves were not affected by task version but were affected by increased WM load. These results suggest that WM emerges from the formation of a dynamic cortical network linking task-specific processes with non-specific, capacity-limited, higher-order attentional processes. Practice effects on the EPs suggested that practice led to the development of a more effective cognitive strategy for dealing with lower-order aspects of task processing, but did not diminish demands made on higher order processes. Thus a simple WM task is shown to be composed of numerous elementary subsecond neural processes whose characteristics vary with type and amount of information being remembered, and amount of practice.
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收藏
页码:563 / 574
页数:12
相关论文
共 83 条
[1]   Dissociation of storage and rehearsal in verbal working memory: Evidence from positron emission tomography [J].
Awh, E ;
Jonides, J ;
Smith, EE ;
Schumacher, EH ;
Koeppe, RA ;
Katz, S .
PSYCHOLOGICAL SCIENCE, 1996, 7 (01) :25-31
[2]   Working memory [J].
Baddeley, Alan .
CURRENT BIOLOGY, 2010, 20 (04) :R136-R140
[3]   A NEUROPHYSIOLOGIC CORRELATE OF VISUAL SHORT-TERM-MEMORY IN HUMANS [J].
BEGLEITER, H ;
PORJESZ, B ;
WANG, W .
ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY, 1993, 87 (01) :46-53
[4]   A parametric study of prefrontal cortex involvement in human working memory [J].
Braver, TS ;
Cohen, JD ;
Nystrom, LE ;
Jonides, J ;
Smith, EE ;
Noll, DC .
NEUROIMAGE, 1997, 5 (01) :49-62
[5]   EPISODIC MULTIREGIONAL CORTICAL COHERENCE AT MULTIPLE FREQUENCIES DURING VISUAL TASK-PERFORMANCE [J].
BRESSLER, SL ;
COPPOLA, R ;
NAKAMURA, R .
NATURE, 1993, 366 (6451) :153-156
[6]   A NEURAL BASIS FOR VISUAL-SEARCH IN INFERIOR TEMPORAL CORTEX [J].
CHELAZZI, L ;
MILLER, EK ;
DUNCAN, J ;
DESIMONE, R .
NATURE, 1993, 363 (6427) :345-347
[7]   Temporal dynamics of brain activation during a working memory task [J].
Cohen, JD ;
Perlstein, WM ;
Braver, TS ;
Nystrom, LE ;
Noll, DC ;
Jonides, J ;
Smith, EE .
NATURE, 1997, 386 (6625) :604-608
[8]   An area specialized for spatial working memory in human frontal cortex [J].
Courtney, SM ;
Petit, L ;
Maisog, JM ;
Ungerleider, LG ;
Haxby, JV .
SCIENCE, 1998, 279 (5355) :1347-1351
[9]   Object and spatial visual working memory activate separate neural systems in human cortex [J].
Courtney, SM ;
Ungerleider, LG ;
Keil, K ;
Haxby, JV .
CEREBRAL CORTEX, 1996, 6 (01) :39-49
[10]   FUNCTION OF THE THALAMIC RETICULAR COMPLEX - THE SEARCHLIGHT HYPOTHESIS [J].
CRICK, F .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES, 1984, 81 (14) :4586-4590