MRI Research Today is a free monthly online journal that collates and summarizes the latest research about MRI, including details on magnetic resonance imaging, neuroimaging, brain tumors.

Assessing the spatiotemporal evolution of neuronal activation with single-trial event-related potentials and functional MRI.

Eichele T, Specht K, Moosmann M, Jongsma ML, Quiroga RQ, Nordby H, Hugdahl K

Department of Biological and Medical Psychology, University of Bergen, 5009 Bergen, Norway. tom.eichele@psybp@uib.no

The brain acts as an integrated information processing system, which methods in cognitive neuroscience have so far depicted in a fragmented fashion. Here, we propose a simple and robust way to integrate functional MRI (fMRI) with single trial event-related potentials (ERP) to provide a more complete spatiotemporal characterization of evoked responses in the human brain. The idea behind the approach is to find brain regions whose fMRI responses can be predicted by paradigm-induced amplitude modulations of simultaneously acquired single trial ERPs. The method was used to study a variant of a two-stimulus auditory target detection (odd-ball) paradigm that manipulated predictability through alternations of stimulus sequences with random or regular target-to-target intervals. In addition to electrophysiologic and hemodynamic evoked responses to auditory targets per se, single-trial modulations were expressed during the latencies of the P2 (170-ms), N2 (200-ms), and P3 (320-ms) components and predicted spatially separated fMRI activation patterns. These spatiotemporal matches, i.e., the prediction of hemodynamic activation by time-variant information from single trial ERPs, permit inferences about regional responses using fMRI with the temporal resolution provided by electrophysiology.

Published 7 December 2005 in Proc Natl Acad Sci U S A, 102(49): 17798-803.
Full-text of this article is available online (may require subscription).

© 2005-2008 MRI Research Today. All Rights Reserved.