Five-dimensional neuroimaging: localization of the time-frequency dynamics of cortical activity.
The spatiotemporal dynamics of cortical oscillations across human brain regions remain poorly understood because of a lack of adequately validated methods for reconstructing such activity from noninvasive electrophysiological data. In this paper, we present a novel adaptive spatial filtering algorithm optimized for robust source time-frequency reconstruction from magnetoencephalography (MEG) and electroencephalography (EEG) data. The efficacy of the method is demonstrated with simulated sources and is also applied to real MEG data from a self-paced finger movement task. The algorithm reliably reveals modulations both in the beta band (12-30 Hz) and high gamma band (65-90 Hz) in sensorimotor cortex. The performance is validated by both across-subjects statistical comparisons and by intracranial electrocorticography (ECoG) data from two epilepsy patients. Interestingly, we also reliably observed high frequency activity (30-300 Hz) in the cerebellum, although with variable locations and frequencies across subjects. The proposed algorithm is highly parallelizable and runs efficiently on modern high-performance computing clusters. This method enables the ultimate promise of MEG and EEG for five-dimensional imaging of space, time, and frequency activity in the brain and renders it applicable for widespread studies of human cortical dynamics during cognition.
Dalal
Sarang S
SS
Department of Radiology, University of California, San Francisco, CA 94143-0628, USA.
Guggisberg
Adrian G
AG
Edwards
Erik
E
Sekihara
Kensuke
K
Findlay
Anne M
AM
Canolty
Ryan T
RT
Berger
Mitchel S
MS
Knight
Robert T
RT
Barbaro
Nicholas M
NM
Kirsch
Heidi E
HE
Nagarajan
Srikantan S
SS
D000328:Adult; D000465:Algorithms; D001611:Beta Rhythm; D002531:Cerebellum / Q000033:anatomy & histology / Q000502:physiology; D002540:Cerebral Cortex / Q000033:anatomy & histology / Q000502:physiology*; D003627:Data Interpretation, Statistical; D004569:Electroencephalography; D004594:Electrophysiology; D005260:Female; D005385:Fingers / Q000294:innervation / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D015225:Magnetoencephalography; D008297:Male; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology; D013003:Somatosensory Cortex / Q000033:anatomy & histology / Q000502:physiology