Parietal contributions to visual working memory depend on task difficulty
The nature of parietal contributions to working memory (WM) remain poorly understood but of considerable interest. We previously reported that posterior parietal damage selectively impaired WM probed by recognition (Berryhill & Olson, 2008a). Recent studies provided support using a neuromodu...
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doaj-7766ca21ffc44a8a94092878705bb2d82020-11-24T22:47:17ZengFrontiers Media S.A.Frontiers in Psychiatry1664-06402012-09-01310.3389/fpsyt.2012.0008129318Parietal contributions to visual working memory depend on task difficultyKevin T. Jones0Marian eBerryhill1University of Nevada, RenoUniversity of Nevada, RenoThe nature of parietal contributions to working memory (WM) remain poorly understood but of considerable interest. We previously reported that posterior parietal damage selectively impaired WM probed by recognition (Berryhill & Olson, 2008a). Recent studies provided support using a neuromodulatory technique, transcranial direct current stimulation (tDCS) applied to the right parietal cortex (P4). These studies confirmed parietal involvement in WM because parietal tDCS altered WM performance: anodal current tDCS improved performance in a change detection task, and cathodal current) tDCS impaired performance on a sequential presentation task. In Experiment 1, we applied cathodal and anodal tDCS to the right parietal cortex and tested participants on both previously used WM tasks. When the WM task was difficult, parietal stimulation (anodal or cathodal) improved WM performance selectively in participants with high WM capacity. In the low WM capacity group, parietal stimulation (anodal or cathodal) impaired WM performance. These nearly equal and opposite effects were only observed when the WM task was challenging, as in the change detection task. Experiment 2 probed the interplay of WM task difficulty and WM capacity in a parametric manner by varying set size in the WM change detection task. Here, the effect of parietal stimulation (anodal or cathodal) on the high WM capacity group followed a linear function as WM task difficulty increased with set size. These findings provide evidence that parietal involvement in WM performance depends on both WM capacity and WM task demands. We discuss these findings in terms of alternative WM strategies employed by low and high WM capacity individuals. We speculate that low WM capacity individuals do not recruit the posterior parietal lobe for WM tasks as efficiently as high WM capacity individuals. Consequently, tDCS provides greater benefit to individuals with high WM capacity.http://journal.frontiersin.org/Journal/10.3389/fpsyt.2012.00081/fullindividual differencesworking memoryPosterior parietal cortextDCSworking memory capacityvisual working memory |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Kevin T. Jones Marian eBerryhill |
spellingShingle |
Kevin T. Jones Marian eBerryhill Parietal contributions to visual working memory depend on task difficulty Frontiers in Psychiatry individual differences working memory Posterior parietal cortex tDCS working memory capacity visual working memory |
author_facet |
Kevin T. Jones Marian eBerryhill |
author_sort |
Kevin T. Jones |
title |
Parietal contributions to visual working memory depend on task difficulty |
title_short |
Parietal contributions to visual working memory depend on task difficulty |
title_full |
Parietal contributions to visual working memory depend on task difficulty |
title_fullStr |
Parietal contributions to visual working memory depend on task difficulty |
title_full_unstemmed |
Parietal contributions to visual working memory depend on task difficulty |
title_sort |
parietal contributions to visual working memory depend on task difficulty |
publisher |
Frontiers Media S.A. |
series |
Frontiers in Psychiatry |
issn |
1664-0640 |
publishDate |
2012-09-01 |
description |
The nature of parietal contributions to working memory (WM) remain poorly understood but of considerable interest. We previously reported that posterior parietal damage selectively impaired WM probed by recognition (Berryhill & Olson, 2008a). Recent studies provided support using a neuromodulatory technique, transcranial direct current stimulation (tDCS) applied to the right parietal cortex (P4). These studies confirmed parietal involvement in WM because parietal tDCS altered WM performance: anodal current tDCS improved performance in a change detection task, and cathodal current) tDCS impaired performance on a sequential presentation task. In Experiment 1, we applied cathodal and anodal tDCS to the right parietal cortex and tested participants on both previously used WM tasks. When the WM task was difficult, parietal stimulation (anodal or cathodal) improved WM performance selectively in participants with high WM capacity. In the low WM capacity group, parietal stimulation (anodal or cathodal) impaired WM performance. These nearly equal and opposite effects were only observed when the WM task was challenging, as in the change detection task. Experiment 2 probed the interplay of WM task difficulty and WM capacity in a parametric manner by varying set size in the WM change detection task. Here, the effect of parietal stimulation (anodal or cathodal) on the high WM capacity group followed a linear function as WM task difficulty increased with set size. These findings provide evidence that parietal involvement in WM performance depends on both WM capacity and WM task demands. We discuss these findings in terms of alternative WM strategies employed by low and high WM capacity individuals. We speculate that low WM capacity individuals do not recruit the posterior parietal lobe for WM tasks as efficiently as high WM capacity individuals. Consequently, tDCS provides greater benefit to individuals with high WM capacity. |
topic |
individual differences working memory Posterior parietal cortex tDCS working memory capacity visual working memory |
url |
http://journal.frontiersin.org/Journal/10.3389/fpsyt.2012.00081/full |
work_keys_str_mv |
AT kevintjones parietalcontributionstovisualworkingmemorydependontaskdifficulty AT marianeberryhill parietalcontributionstovisualworkingmemorydependontaskdifficulty |
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