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Open AccessJournal ArticleDOI

Temporal dynamics of brain activation during a working memory task

TLDR
Functional magnetic resonance imaging is used to examine brain activation in human subjects during performance of a working memory task and to show that prefrontal cortex along with parietal cortex appears to play a role in active maintenance.
Abstract
Working memory is responsible for the short-term storage and online manipulation of information necessary for higher cognitive functions, such as language, planning and problem-solving. Traditionally, working memory has been divided into two types of processes: executive control (governing the encoding manipulation and retrieval of information in working memory) and active maintenance (keeping information available 'online'). It has also been proposed that these two types of processes may be subserved by distinct cortical structures, with the prefrontal cortex housing the executive control processes, and more posterior regions housing the content-specific buffers (for example verbal versus visuospatial) responsible for active maintenance. However, studies in non-human primates suggest that dorsolateral regions of the prefrontal cortex may also be involved in active maintenance. We have used functional magnetic resonance imaging to examine brain activation in human subjects during performance of a working memory task. We used the temporal resolution of this technique to examine the dynamics of regional activation, and to show that prefrontal cortex along with parietal cortex appears to play a role in active maintenance.

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Journal ArticleDOI

An integrative theory of prefrontal cortex function

TL;DR: It is proposed that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them, which provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task.
Book ChapterDOI

Chapter 11 Working memory

TL;DR: This chapter demonstrates the functional importance of dopamine to working memory function in several ways and demonstrates that a network of brain regions, including the prefrontal cortex, is critical for the active maintenance of internal representations.
Journal ArticleDOI

The magical number 4 in short-term memory: a reconsideration of mental storage capacity.

TL;DR: A wide variety of data on capacity limits suggesting that the smaller capacity limit in short-term memory tasks is real is brought together and a capacity limit for the focus of attention is proposed.
Journal ArticleDOI

Working memory: looking back and looking forward

TL;DR: The concept of working memory proposes that a dedicated system maintains and stores information in the short term, and that this system underlies human thought processes.
Journal ArticleDOI

An fMRI Investigation of Emotional Engagement in Moral Judgment

TL;DR: It is argued that moral dilemmas vary systematically in the extent to which they engage emotional processing and that these variations in emotional engagement influence moral judgment.
References
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Journal ArticleDOI

AFNI: software for analysis and visualization of functional magnetic resonance neuroimages

TL;DR: A package of computer programs for analysis and visualization of three-dimensional human brain functional magnetic resonance imaging (FMRI) results is described and techniques for automatically generating transformed functional data sets from manually labeled anatomical data sets are described.
Journal ArticleDOI

Dynamic magnetic resonance imaging of human brain activity during primary sensory stimulation.

TL;DR: In this paper, a series of images were acquired continuously with the same imaging pulse sequence (either gradient echo or spin-echo inversion recovery) during task activation, and a significant increase in signal intensity (paired t test; P less than 0.001) of 1.8% +/- 0.9% was observed in the primary visual cortex (V1) of seven normal volunteers.
Journal ArticleDOI

Intrinsic signal changes accompanying sensory stimulation: functional brain mapping with magnetic resonance imaging

TL;DR: It is reported that visual stimulation produces an easily detectable (5-20%) transient increase in the intensity of water proton magnetic resonance signals in human primary visual cortex in gradient echo images at 4-T magnetic-field strength.
Book

From Neuropsychology to Mental Structure

TL;DR: Cognitive neuropsychology is a branch of psychology that investigates the role of language in the development of personality and the role that language plays in the formation of identity.
Journal ArticleDOI

Improved assessment of significant activation in functional magnetic resonance imaging (fMRI) : use of a cluster-size threshold

TL;DR: In this article, an alternative approach, which relies on the assumption that areas of true neural activity will tend to stimulate signal changes over contiguous pixels, is presented, which can improve statistical power by as much as fivefold over techniques that rely solely on adjusting per pixel false positive probabilities.
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