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Interrupting the "stream of consciousness": an fMRI investigation. Neuroimage 2006 Feb 15;29(4):1185-91

Date

11/05/2005

Pubmed ID

16269249

Pubmed Central ID

PMC1634934

DOI

10.1016/j.neuroimage.2005.09.030

Scopus ID

2-s2.0-31844444843   359 Citations

Abstract

In functional neuroimaging, a local decrease in blood flow during an active task, relative to a "resting" baseline, is referred to as task-induced deactivation (TID). TID may occur when resources shift from ongoing, internally generated processing typical of "resting" states to processing required by an exogenous task. We previously found specific brain regions in which TID increased as task processing demands increased. When engaged in an exogenous cognitive task, reallocation of resources from areas involved in internal processing should result in suspension of that processing. Self-reported thought content has been used as an indicator of the extent of internal processing activity. We investigated the relationship between TID and task-unrelated thought (TUT) frequency using an auditory target detection task with seven levels of task difficulty. At varied intervals during task performance, subjects indicated whether they were experiencing a TUT. We expected TUT frequency to decrease as task demands increased and for this pattern to correlate with TID magnitude across conditions. Generally, fewer TUTs were reported during difficult task conditions than during easier conditions. As TID magnitude increased across task conditions, the frequency of TUTs declined (r = 0.90, P = 0.005). Four left hemisphere regions (posterior parieto-occipital cortex, anterior cingulate gyrus, fusiform gyrus, and middle frontal gyrus) showed strong relationships between TUTs and TID (r > 0.79, P < 0.05 corrected). As these regions have been implicated in semantic processing and self-referential thought, the findings support the suspension of internal cognitive processing as one mechanism for TID.

Author List

McKiernan KA, D'Angelo BR, Kaufman JN, Binder JR

Authors

Jeffrey R. Binder MD Professor in the Neurology department at Medical College of Wisconsin
Benjamin R. D'Angelo PhD Assistant Professor in the Psychiatry department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Adolescent
Adult
Arousal
Attention
Awareness
Cerebral Cortex
Consciousness
Dominance, Cerebral
Female
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging
Male
Middle Aged
Oxygen
Pitch Perception
Regional Blood Flow
Statistics as Topic
Thinking