کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
335927 547056 2007 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dissociating the effects of Sternberg working memory demands in prefrontal cortex
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی روانپزشکی بیولوژیکی
پیش نمایش صفحه اول مقاله
Dissociating the effects of Sternberg working memory demands in prefrontal cortex
چکیده انگلیسی

Earlier neuroimaging studies of working memory (WM) have demonstrated that dorsolateral prefrontal cortex (DLPFC) activity increases as maintenance and load demand increases. However, few studies have carefully disambiguated these two WM processes at the behavioral and physiological levels. The objective of the present functional resonance imaging (fMRI) study was to map within prefrontal cortex locales that are selectively load sensitive, delay sensitive, or both. We studied 18 right-handed normal subjects with fMRI at 3 Tesla during a block design version of the Sternberg task. WM load was manipulated by varying the memory set size (3, 5, or 8 letters). The effect of memory maintenance was examined by employing two time delays (1 s and 6 s) between the letter set and probe stimuli. The DLPFC was strongly activated in load manipulation, whereas activation as a function of delay was restricted to the left premotor regions and Broca's areas. Moreover, regions of prefrontal cortex on the right (BA 46) were found to be exclusively affected by load. These results suggest the possibility that top–down modulation of attention or cognitive control at encoding and/or decisionmaking may be mediated by these areas.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Psychiatry Research: Neuroimaging - Volume 154, Issue 2, 28 February 2007, Pages 103–114
نویسندگان
, , , , , , , ,