Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/7344
Appears in Collections:Psychology Journal Articles
Peer Review Status: Refereed
Title: Mixed blocked/event-related designs separate transient and sustained activity in fMRI
Authors: Visscher, Kristina M
Miezin, Francis M
Kelly, James E
Buckner, Randy
Donaldson, David
McAvoy, Mark P
Bhalodia, Vidya M
Petersen, Steve E
Contact Email: d.i.donaldson@stir.ac.uk
Issue Date: Aug-2003
Publisher: Elsevier
Citation: Visscher KM, Miezin FM, Kelly JE, Buckner R, Donaldson D, McAvoy MP, Bhalodia VM & Petersen SE (2003) Mixed blocked/event-related designs separate transient and sustained activity in fMRI, NeuroImage, 19 (4), pp. 1694-1708.
Abstract: Recent functional magnetic resonance imaging (fMRI) studies using mixed blocked/ event-related designs have shown activity consistent with separable sustained task-related processes and transient trial-related processes. In the mixed design, control blocks are intermixed with task blocks, during which trials are presented at varying intervals. Two studies were conducted to assess the ability of this design to detect and dissociate sustained task-related from transient trial-related activity. Analyses on both simulated and empirical data were performed by using the general linear model with a shape assumed for sustained effects, but not transient effects. In the first study, simulated data were produced with sustained time courses, transient time courses, and the sum of both together. Analyses of these data showed appropriate parsing of sustained and transient activity in all three cases. For the empirical fMRI experiment, counterphase-flickering checkerboard stimuli were constructed to produce sustained, transient, and combined sustained and transient responses in visual cortex. As with the simulation, appropriate parsing of sustained and transient activity was seen in all three cases; i.e., sustained stimuli produced sustained time courses and transient stimuli produced transient time courses. Combined stimuli produced both transient and sustained time courses. Critically, transient stimuli alone did not produce spurious positive sustained responses; sustained stimuli alone produced negligible spurious transient time courses. The results of these two studies along with supplemental simulations provide strong evidence that mixed designs are an effective tool for separating transient, trial-related activity from sustained activity in fMRI experiments. Mixed designs can allow researchers a means to examine brain activity associated with sustained processes, potentially related to task-level control signals.
Type: Journal Article
URI: http://hdl.handle.net/1893/7344
DOI Link: http://dx.doi.org/10.1016/S1053-8119(03)00178-2
Rights: The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study.
Affiliation: Washington University In Saint Louis
Washington University In Saint Louis
Washington University In Saint Louis
Washington University In Saint Louis
Psychology
Washington University In Saint Louis
Washington University In Saint Louis
Washington University In Saint Louis

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