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Brain Topography

, Volume 6, Issue 1, pp 65–78 | Cite as

Ocular artifacts in recording EEGs and event-related potentials II: Source dipoles and source components

  • Otavio G. Lins
  • Terence W. Picton
  • Patrick Berg
  • Michael Scherg
Article

Summary

The source dipoles for blinks point radially whereas the source dipoles for saccades point tangentially, in the direction of the eye movement. This indicates that blink potentials are not generated by eye movements but by the eyelid sliding down over the positively charged cornea. Dipole source dipole analysis shows that the “rider artifact” at the onset of upward and lateral saccades is caused by the eyelid as it lags a little behind the eyes at the beginning of the movement. Dipole source analysis allows both the EEG and the EOG to be modeled simultaneously and EOG generators to be distinguished from nearby EEG generators. Ocular source components can be calculated from a principal component analysis of EEG and EOG recordings during blinks and saccades. The effectiveness of propagation factors, source dipoles and source components in removing ocular artifacts from EEG samples was assessed. The most effective correction procedure uses source components.

Key words

Electro-oculogram EOG EEG artifacts Source analysis Principal component analysis 

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Copyright information

© Human Sciences Press, Inc 1993

Authors and Affiliations

  • Otavio G. Lins
    • 1
  • Terence W. Picton
    • 1
  • Patrick Berg
    • 2
  • Michael Scherg
    • 3
  1. 1.Human Neurosciences Research UnitUniversity of OttawaCanada
  2. 2.Department of PsychologyUniversity of KonstanzGermany
  3. 3.Department of NeuroscienceAlbert Einstein College of MedicineBronxUSA

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