title: A study of the electro-haemodynamic coupling using simultaneously acquired intracranial EEG and fMRI data in humans.
abstract: In current fMRI studies designed to map BOLD changes related to interictal epileptiform discharges (IED), which are recorded on simultaneous EEG, the information contained in the morphology and field extent of the EEG events is exclusively used for their classification. Usually, a BOLD predictor based on IED onset times alone is constructed, effectively treating all events as identical. We used intracranial EEG (icEEG)-fMRI data simultaneously recorded in humans to investigate the effect of including any of the features: amplitude, width (duration), slope of the rising phase, energy (area under the curve), or spatial field extent (number of contacts over which the sharp wave was observed) of the fast wave of the IED (the sharp wave), into the BOLD model, to better understand the neurophysiological origin of sharp wave-related BOLD changes, in the immediate vicinity of the recording contacts. Among the features considered, the width was the only one found to explain a significant amount of additional variance, suggesting that the amplitude of the BOLD signal depends more on the duration of the underlying field potential (reflected in the sharp wave width) than on the degree of neuronal activity synchrony (reflected in the sharp wave amplitude), and, consequently, that including inter-event variations of the sharp wave width in the BOLD signal model may increase the sensitivity of forthcoming EEG-fMRI studies of epileptic activity.
authors: Dept. of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom; Institute for Systems and Robotics and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal. Electronic address: tigoncalvesmurta@gmail.com.
authors: T
authors: T
authors: Murta
authors: Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
authors: L
authors: L
authors: Hu
authors: UCL Institute of Child Heath, London, United Kingdom.
authors: T M
authors: TM
authors: Tierney
authors: Dept. of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom.
authors: U J
authors: UJ
authors: Chaudhary
authors: Dept. of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom.
authors: M C
authors: MC
authors: Walker
authors: UCL Institute of Child Heath, London, United Kingdom.
authors: D W
authors: DW
authors: Carmichael
authors: Institute for Systems and Robotics and Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal.
authors: P
authors: P
authors: Figueiredo
authors: Dept. of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom.
authors: L
authors: L
authors: Lemieux
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000502:physiology*; D000069279:Drug Resistant Epilepsy / Q000503:physiopathology; D004569:Electroencephalography / Q000379:methods*; D058407:Electroencephalography Phase Synchronization / Q000502:physiology; D059907:Functional Neuroimaging / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D000069336:Neurovascular Coupling / Q000502:physiology*
keywords: BOLD; Electro-haemodynamic coupling; Intracranial EEG; Sharp wave; fMRI