Abstract #0107

Simultaneous Intracranial EEG-fMRI in Humans Suggests that High Gamma Frequencies are the Closest Neurophysiological Correlate of BOLD fMRI

David William Carmichael¹, Serge Vulliemoz^{1, 2}, Roman Rodionov¹, Matthew Walker¹, Karin Rosenkranz¹, Andrew McEvoy³, Louis Lemieux^{1,
4}

¹Clinical & Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom; ²Epilepsy Unit, University Hospital & University of Geneva, Geneva, Switzerland; ³Victor Horsley Dept. Neurosurgery, National Hospital for Neurology & Neurosurgery, London, United Kingdom; ⁴MRI Unit , National Society for Epilepsy, Chalfont St Peter, United Kingdom

We investigated EEG-fMRI coupling in a simple motor task and at rest by simultaneously recording intracranial EEG and fMRI in human sensorimotor cortex. One epilepsy patient, implanted for presurgical evaluation with electrodes covering sensorimotor cortex, was scanned following a strict safety protocol. EEG-frequency specific predictors of the BOLD fMRI response were calculated and correlated with fMRI signal changes from the task-activated sensorimotor region. Our results suggest that high gamma frequencies are the most closely correlated to BOLD-fMRI during the task but not during rest and that the peak correlation frequency is highly dependent on measurement location.