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An investigation of the relationship between BOLD and perfusion signal changes during epileptic generalised spike wave activity

Carmichael, D.W.; Hamandi, K.; Laufs, H.; Duncan, J.S.; Thomas, D.L.; Lemieux, L.; (2008) An investigation of the relationship between BOLD and perfusion signal changes during epileptic generalised spike wave activity. Magnetic Resonance Imaging , 26 (7) pp. 870-873. 10.1016/j.mri.2008.01.041. Green open access

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Abstract

In pathological conditions interpretation of functional magnetic resonance imaging (fMRI) results can be difficult. This is due to a reliance on the assumed coupling between neuronal activity and changes in cerebral blood flow (CBF) and oxygenation. We wanted to investigate the coupling between blood oxygen level dependant contrast (BOLD) and CBF time courses in epilepsy patients with generalised spike wave activity (GSW) to better understand the underlying mechanisms behind the EEG-fMRI signal changes observed, especially in regions of negative BOLD response (NBR). Four patients with frequent GSW were scanned with simultaneous electroencephalographic (EEG)-fMRI with BOLD and arterial spin labeling (ASL) sequences. We examined the relationship between simultaneous CBF and BOLD measurements by looking at the correlation of the two signals in terms of percentage signal change on a voxel-by-voxel basis. This method is not reliant on coincident activation. BOLD and CBF were positively correlated in patients with epilepsy during background EEG activity and GSW. The subject average value of the ΔCBF/ΔBOLD slope lay between +19 and +36 and also showed spatial variation which could indicate areas with altered vascular response. There was not a significant difference between ΔCBF/ΔBOLD during GSW, suggesting that neurovascular coupling to BOLD signal is generally maintained between states and, in particular, within areas of NBR.

Type: Article
Title: An investigation of the relationship between BOLD and perfusion signal changes during epileptic generalised spike wave activity
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.mri.2008.01.041
Publisher version: http://dx.doi.org/10.1016/j.mri.2008.01.041
Language: English
Keywords: EEG-fMRI, generalized spike wave, BOLD, perfusion, correlation, neurovascular coupling
UCL classification: UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Clinical and Experimental Epilepsy
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Brain Repair and Rehabilitation
URI: https://discovery.ucl.ac.uk/id/eprint/20267
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