Document Detail


Stimulus frequency dependence of blood oxygenation level-dependent functional magnetic resonance imaging signals in the somatosensory cortex of rats.
MedLine Citation:
PMID:  18602178     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Understanding the mechanism of coupling between neuronal events and hemodynamic responses is important in non-invasive functional imaging of the brain. The stimulus frequency dependence of hemodynamic responses has been studied using a rat somatosensory cortex model; most results for short stimulus durations reveal peak frequencies at which the hemodynamic response is maximized. However, such peak frequencies have not been observed in studies using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signals with long stimulus durations. To clarify whether the stimulus frequency dependence of BOLD signals depends on the stimulus duration, we measured BOLD signals at 7 T with short- and long-stimulus durations for stimulating rat forepaw at 1-10 Hz using spin-echo echo-planar imaging to enhance changes in activation focus. For both these durations, BOLD signals were significantly higher at stimulus frequencies of 3 or 5 Hz in agreement with the results of previous studies using optical techniques. Our results show that stimulus duration has little influence on the stimulus frequency dependence of BOLD signals in the rat somatosensory model. The discrepant results of most previous fMRI studies using gradient-echo sequence may be ascribed to the difference of imaging to enhance activation focus or draining vein.
Authors:
Ikuhiro Kida; Toru Yamamoto
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-07-03
Journal Detail:
Title:  Neuroscience research     Volume:  62     ISSN:  0168-0102     ISO Abbreviation:  Neurosci. Res.     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-08-04     Completed Date:  2008-10-24     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8500749     Medline TA:  Neurosci Res     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  25-31     Citation Subset:  IM    
Affiliation:
Division of Oral Functional Science, Graduate School of Dental Medicine, Hokkaido University, Hokkaido, Japan. ikida@den.hokudai.ac.jp
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MeSH Terms
Descriptor/Qualifier:
Afferent Pathways / physiology*
Animals
Brain Mapping
Cerebral Arteries / physiology
Cerebrovascular Circulation / physiology*
Energy Metabolism / physiology
Magnetic Resonance Imaging
Male
Models, Animal
Optics and Photonics
Oxygen / blood*
Oxygen Consumption / physiology*
Physical Stimulation
Rats
Rats, Sprague-Dawley
Signal Processing, Computer-Assisted
Somatosensory Cortex / blood supply,  metabolism*
Touch / physiology*
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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