Title :
Dynamic MEG imaging of focal neuronal sources
Author :
Phillips, James W. ; Leahy, Richard M. ; Mosher, John C.
Author_Institution :
Signal & Image Process. Inst., Univ. of Southern California, Los Angeles, CA, USA
Abstract :
The authors describe inverse methods for using the magnetoencephalogram (MEG) to image neural current sources associated with functional activation in the cerebral cortex. A Bayesian formulation is presented that is based on a Gibbs prior which reflects the sparse, focal nature of neural activation. The model includes a dynamic component so that the authors can utilize the full spatio-temporal data record to reconstruct a sequence of images reflecting changes in the current source amplitudes during activation. The model consists of the product of a binary field, representing the areas of activation in the cerebral cortex, and a time series at each site which represents the dynamic changes in the source amplitudes at the active sites. The authors´ estimation methods are based on the optimization of three different functions of the posterior density. Each of these methods requires the estimation of a binary field which the authors compute using a mean field annealing method. They demonstrate and compare their methods in application to computer generated and experimental phantom data
Keywords :
Bayes methods; image reconstruction; image sequences; inverse problems; magnetoencephalography; medical image processing; neurophysiology; Bayesian formulation; Gibbs prior; active sites; binary field; cerebral cortex; computer generated data; dynamic MEG imaging; experimental phantom data; focal neuronal sources; functional activation; mean field annealing method; neural current sources imaging; posterior density; Annealing; Application software; Bayesian methods; Brain modeling; Cerebral cortex; Computer applications; Image reconstruction; Imaging phantoms; Inverse problems; Optimization methods;
Conference_Titel :
Nuclear Science Symposium, 1996. Conference Record., 1996 IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
0-7803-3534-1
DOI :
10.1109/NSSMIC.1996.588011