MEG-EEG Source Estimation Approaches: A Spectrum of Purpose-Built Optimal Tools

Explore MEG/EEG source estimation approaches in this comprehensive lecture by Matti Hämäläinen from Massachusetts General Hospital. Delve into the intricacies of brain space analysis, forward models, and cortical source constraints. Examine various source estimation techniques, including current-dipole models, multidipole models, and minimum-norm estimates (MNE). Discover applications in studying cortical rhythms, visual processing, and neurological disorders. Learn about spatiotemporal analysis, group studies, and connectivity assessments in autism spectrum disorder (ASD). Gain insights into the challenges and solutions in MEG/EEG source localization, from basic principles to advanced methodologies and real-world applications in neuroscience research.

Intro
Source (brain) space instead of sensor space
Contents
Cortical Beta and Gamma Rhythm Resting-State Networks Follow Distinct Maturation Trajectories
Neural sources of MEG and EEG
Forward models for MEG and EEG
Primary currents in the cortex
Cortical Source Location Constraints
Inflated Cortex
Tangential, radial, and tilted sources
MEG and EEG sensitivity to cortical sources
Orthogonal patterns: MEG (or EEG) may benefit
An MEG System
Magnetometers and planar gradiometers
Modulation of the Alpha and Mu Rhythms
Silent sources
Many Ways to Make the Problem Unique
Terminology
Example: The time-varying current-dipole model
Dipolar field pattern: Focal sources
Are dipoles good for extended sources?
Filling
Partly Heuristic strategies
Multidipole Model for SEF
The Source Locations are consistent
Dynamics of Cortical Activity in a Picture Naming Task
Visual Stability During Eye Blinks
Viable Explanation
Cerebellar activity associated with saccades
Source locations and time courses
Imitation of orofacial gestures
Spaliolemporal analysis of the somalomotor
Dipole models: Summary
Source modeling priors
Spatio-Temporal Structure of Source Estimates
Early retinotopic mapping with MNE
Effect of the orientation constraint
Spatial dispersion of cortically-constrained MNE
Visual percepts of an ambiguous scene
Group analysis
Long-Range Connectivity Differences Between ASD and TD Subjects (MEG)
Functional definition of FFA
Local Connectivity Different in FFA only
MNE and friends: Summary
Inverse problem ambiguity