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Hinrichs H, Scholz M, Tempelmann C, Woldorff MG, Dale AM, Heinze HJ.

Deconvolution of Event-Related fMRI Responses in Fast-Rate Experimental Designs: Tracking Amplitude Variations

fMRIDC Accession Number: 2-2000-11158
Journal of Cognitive Neuroscience 2000 Nov ;12(suppl. 2): p.76-89
PubMed ID: 11506649 (off-site link)
 Study Meta-Data

Recent developments towards event-related functional magnetic resonance imaging (ErfMRI) has greatly extended the range of experimental designs. If the events occur in rapid succession, the corresponding time-locked responses overlap significantly and need to be deconvolved in order to separate the contributions of different events. Here we present a deconvolution approach, which is especially aimed at the analysis of fMRI data where sequence or context related responses are expected. For this purpose we make the assumption of a hemodynamic response function (HDR) with constant yet not predefined shape but with possibly variable amplitudes. This approach reduces the number of variables to be estimated but still keeps the solutions flexible with respect to the shape. Consequently, statistical efficiency is improved. Temporal variations of the HDR strength are directly indicated by the amplitudes derived by the algorithm. Both the estimation efficiency and statistical inference are further supported by an improved estimation of the noise covariance. Using synthesized data sets, both differently shaped HDRs and varying amplitude factors were correctly identified. The gain in statistical sensitivity led to improved ratios of false and true-positive detection rates for synthetic activations in these data In as event-related fMRI experiment with a human subject, different HDR amplitudes could be derived corresponding to stimulation at different visual stimulus contrasts. Finally, in a visual spatial attention experiment we obtained different fMRI response amplitudes depending on the sequences of attention conditions.

Supplemental Information

Language: English
fMRIDC Comments: Dataset Size: 99M Available on 2 CDs
Country: Germany
Magnetic Field Strength: 1.5T
Scanner Manufacturer: GE Signa LX NV/i
Analysis Software: SPM 99
Cognitive Domain: Visual Attention
Subjects: 6
Age Range: Not given in paper
Functional Runs: 8
Has anatomical data
Has behavioral data
Has raw image data
Has high-res images
Comments on Deconvolution of Event-Related fMRI Responses in Fast-Rate Experimental Designs: Tracking Amplitude Variations by interch on August 23, 2006 @05:15
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