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Activity Number:
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63
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Type:
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Contributed
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Date/Time:
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Sunday, August 6, 2006 : 4:00 PM to 5:50 PM
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Sponsor:
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Biometrics Section
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| Abstract - #305556 |
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Title:
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Intrinsic Voxel Correlation in fMRI
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Author(s):
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Daniel Rowe*+ and Raymond G. Hoffmann
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Companies:
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Medical College of Wisconsin and Medical College of Wisconsin
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Address:
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Department of Biophysics, Milwaukee, WI, 53226,
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Keywords:
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fMRI ; voxel correlation ; k-space ; brain imaging ; spatial frequency ; connectivity
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Abstract:
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In fMRI, complex-valued spatial frequency measurements are acquired on a rectangular grid. These measurements are transformed to a complex-valued image by inverse Fourier transform. It is known that image voxels are spatially correlated. A property of the inverse Fourier transformation is that (un)correlated spatial frequency measurements yield spatially (un)correlated voxel measurements and vice versa. Spatially correlated voxels result from correlated spatial frequency measurements. This work describes the resulting correlation structure between complex-valued voxel measurements. A real-valued representation for complex-valued measurements is introduced with an associated multivariate normal distribution. An implication is that one source of voxel correlation may be attributed to temporally autocorrelated spatial frequencies. True voxel connectivity may be less than thought previously.
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