fMRI of Deep Brain Stimulation at the Rat Ventral Posteromedial Thalamus

Background: Functional magnetic resonance imaging (fMRI) of deep brain stimulation (DBS) has potentials to reveal neuroanatomical connectivity of a specific brain region in vivo. Objective: This study aimed to demonstrate frequency and amplitude tunings of the thalamocortical tract using DBS fMRI at the rat ventral posteromedial thalamus. Methods: Blood oxygenation level dependent (BOLD) fMRI data were acquired in a total of twelve rats at a high-field 11.7 T MRI scanner with modulation of nine stimulus frequencies (1-40 Hz) and seven stimulus amplitudes (0.2-3.6 mA). Results: BOLD response in the barrel cortex peaked at 25 Hz. The response increased with stimulus amplitude and reached a plateau at 1 mA. Cortical spreading depolarization (CSD) was observed occasionally after DBS that carries >10% BOLD waves spanning the entire ipsilateral cortex. Conclusion: fMRI is sensitive to the frequency effect of DBS and has potential to investigate the function of a particular neuroanatomical pathway. (C) 2014 Elsevier Inc. All rights reserved.