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Alpha and kappa electroencephalogram activity in eyeless subjects
Science (New York, N.Y.)
|March 19, 1971
Summary
Alpha and kappa electroencephalogram (EEG) activity originates in the brain, not from eye movements. Studies confirm EEG signals persist even without eyes, refuting artifact theories.
Area of Science:
- Neuroscience
- Ophthalmology
- Electrophysiology
Background:
- Electroencephalogram (EEG) activity, specifically alpha and kappa rhythms, has been questioned as being artifacts of eye movements.
- Previous research has not definitively ruled out ocular sources for these brainwave patterns.
Purpose of the Study:
- To investigate the origin of alpha and kappa electroencephalogram (EEG) activity.
- To determine if EEG rhythms are generated in the brain or are artifacts of ocular functions.
Main Methods:
- Review and citation of existing data excluding ocular sources like corneoretinal potential, extraocular muscle tremor, eye position, accommodation, and eye flutter.
- Analysis of EEG activity in a subject who had undergone bilateral eye enucleation (both eyes removed).
- Examination of EEG in subjects with unilateral eye and extraocular muscle removal.
Main Results:
- Data presented effectively eliminate ocular potentials and movements as sources of alpha and kappa EEG activity.
- A subject with no eyes exhibited normal alpha and kappa EEG activity.
- Unilateral eye removal did not result in significant left-right alpha activity differences.
Conclusions:
- Alpha and kappa EEG activity are of cerebral origin.
- Ocular artifacts do not account for the observed alpha and kappa EEG rhythms.
- These findings support the endogenous generation of specific EEG frequencies within the brain.