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Sparse temporal sampling in auditory fMRI
DOI:10.1002/(SICI)1097-0193(1999)7:3<213::AID-HBM5>3.0.CO;2-N.png)
摘要
En 中文
The use of functional magnetic resonance imaging (fMRI) to explore central auditory function may be compromised by the intense bursts of stray acoustic noise produced by the scanner whenever the magnetic resonance signal is read out. We present results evaluating the use of one method to reduce the effect of the scanner noise: sparse temporal sampling. Using this technique, single volumes of brain images are acquired at the end of stimulus and baseline conditions. To optimize detection of the activation, images are taken near to the maxima and minima of the hemodynamic response during the experimental cycle. Thus, the effective auditory stimulus for the activation is not masked by the scanner noise. In experiment 1, the course of the hemodynamic response to auditory stimulation was mapped during continuous task performance. The mean peak of the response was at 10.5 sec after stimulus onset, with little further change until stimulus offset. In experiment 2, sparse imaging was used to acquire activation images. Despite the fewer samples with sparse imaging, this method successfully delimited broadly the same regions of activation as conventional continuous imaging. However, the mean percentage MR signal change within the region of interest was greater using sparse imaging. Auditory experiments that use continuous imaging methods may measure activation that is a result of an interaction between the stimulus and task factors (e.g., attentive effort) induced by the intense background noise. We suggest that sparse imaging is advantageous in auditory experiments as it ensures that the obtained activation depends on the stimulus alone. (C) 1999 Wiley-Liss, Inc.
Keyword:
sparse imaging
scanner noise interference
MR signal-to-noise ratio
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3.3
论文数:
6.8K
被引数:
2.6W
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引用论文
Tonotopy in human auditory cortex examined with functional magnetic resonance imaging功能性磁共振成像检查人类听觉皮层中的Tonotopy
HUMAN BRAIN MAPPING
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