title: Functional MRI during Hippocampal Deep Brain Stimulation in the Healthy Rat Brain.
abstract: Deep Brain Stimulation (DBS) is a promising treatment for neurological and psychiatric disorders. The mechanism of action and the effects of electrical fields administered to the brain by means of an electrode remain to be elucidated. The effects of DBS have been investigated primarily by electrophysiological and neurochemical studies, which lack the ability to investigate DBS-related responses on a whole-brain scale. Visualization of whole-brain effects of DBS requires functional imaging techniques such as functional Magnetic Resonance Imaging (fMRI), which reflects changes in blood oxygen level dependent (BOLD) responses throughout the entire brain volume. In order to visualize BOLD responses induced by DBS, we have developed an MRI-compatible electrode and an acquisition protocol to perform DBS during BOLD fMRI. In this study, we investigate whether DBS during fMRI is valuable to study local and whole-brain effects of hippocampal DBS and to investigate the changes induced by different stimulation intensities. Seven rats were stereotactically implanted with a custom-made MRI-compatible DBS-electrode in the right hippocampus. High frequency Poisson distributed stimulation was applied using a block-design paradigm. Data were processed by means of Independent Component Analysis. Clusters were considered significant when p-values were <0.05 after correction for multiple comparisons. Our data indicate that real-time hippocampal DBS evokes a bilateral BOLD response in hippocampal and other mesolimbic structures, depending on the applied stimulation intensity. We conclude that simultaneous DBS and fMRI can be used to detect local and whole-brain responses to circuit activation with different stimulation intensities, making this technique potentially powerful for exploration of cerebral changes in response to DBS for both preclinical and clinical DBS.
authors.affiliation: Medical Image and Signal Processing Group, Ghent University-iMinds Medical IT department, Ghent, Belgium.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Van Den Berge
authors.affiliation: Medical Image and Signal Processing Group, Ghent University-iMinds Medical IT department, Ghent, Belgium.
authors.forename: Christian
authors.initials: C
authors.lastname: Vanhove
authors.affiliation: Medical Image and Signal Processing Group, Ghent University-iMinds Medical IT department, Ghent, Belgium.
authors.forename: Benedicte
authors.initials: B
authors.lastname: Descamps
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Ine
authors.initials: I
authors.lastname: Dauwe
authors.affiliation: Medical Image and Signal Processing Group, Ghent University-iMinds Medical IT department, Ghent, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: van Mierlo
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Kristl
authors.initials: K
authors.lastname: Vonck
authors.affiliation: Medical Image and Signal Processing Group, Ghent University-iMinds Medical IT department, Ghent, Belgium.
authors.forename: Vincent
authors.initials: V
authors.lastname: Keereman
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Robrecht
authors.initials: R
authors.lastname: Raedt
authors.affiliation: Laboratory for Clinical and Experimental Neurophysiology, Neurobiology and Neuropsychology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: Boon
authors.affiliation: Medical Image and Signal Processing Group, Ghent University-iMinds Medical IT department, Ghent, Belgium.
authors.forename: Roel
authors.initials: R
authors.lastname: Van Holen
mesh_terms: D000818:Animals; D046690:Deep Brain Stimulation; D059907:Functional Neuroimaging; D006624:Hippocampus / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley