Research › QEEG, Methods & Mechanisms
The localization of equivalent dipoles of EEG sources by the application of electrical field theory
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Study at a glance
- Area
- QEEG, Methods & Mechanisms
- Study type
- Observational study
- Authors
- Henderson CJ, Butler SR, Glass A
- Journal
- Electroencephalography and Clinical Neurophysiology
- Year
- 1975
- Protocol
- single equivalent dipole source localization
Key findings
- Mean error between actual and computed dipole positions was on the order of 1 cm in both physical models
- Accuracy held in the skull model even though potentials passing through the skull were attenuated by 80%
- Correctly localized blink artifact generators within the remaining eye of a one-eyed subject
- Alpha rhythm localized posteriorly, consistent with generation mainly by posterior cortex
Describes a computer technique for estimating the position, strength and orientation of a single equivalent dipole behind EEG activity from scalp potentials, using equations for a dipole in a spherical conductor. Tested in a saline-filled bowl and in a human skull model with simulated scalp, it located the dipole to within about 1 cm. In people, it placed blink artifact sources in the eye, visual evoked response generators in posterior brain regions, and the alpha rhythm in posterior cortex. The authors also discuss accuracy factors and the limits of one-dipole models.