Randomized event-related experimental designs allow for extremely rapid presentation rates using functional MRI.

Published

Journal Article

Previous studies have shown that hemodynamic response overlap severely limits the maximum presentation rate with event-related functional MRI (fMRI) using fixed intertrial experimental designs. Here we demonstrate that the use of randomized experimental designs can largely overcome this limitation, thereby allowing for event-related fMRI experiments with extremely rapid presentation rates. In the first experiment, fMRI time courses were simulated using a fixed intertrial interval design with intervals of 16, 3, and 1 s, and using a randomized design having the same mean intertrial intervals. We found that using fixed intertrial interval designs the transient information decreased with decreasing intertrial intervals, whereas using randomized designs the transient information increased with decreasing mean intertrial intervals. In a second experiment, fMRI data were collected from two subjects using a randomized paradigm with visual hemifield stimuli presented randomly every 500 ms. Robust event-related activation maps and hemodynamic response estimates were obtained. These results demonstrate the feasibility of performing event-related fMRI experiments with rapid, randomized paradigms identical to those used in electrophysiological and behavioral studies, thereby expanding the applicability of event-related fMRI to a whole new range of cognitive neurosciences questions and paradigms.

Full Text

Duke Authors

Cited Authors

  • Burock, MA; Buckner, RL; Woldorff, MG; Rosen, BR; Dale, AM

Published Date

  • November 16, 1998

Published In

Volume / Issue

  • 9 / 16

Start / End Page

  • 3735 - 3739

PubMed ID

  • 9858388

Pubmed Central ID

  • 9858388

International Standard Serial Number (ISSN)

  • 0959-4965

Digital Object Identifier (DOI)

  • 10.1097/00001756-199811160-00030

Language

  • eng

Conference Location

  • England