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Problem of signal contamination in interhemispheric dual‐sided subdural electrodes
Author(s) -
Nune George,
Winawer Jonathan,
Rauschecker Andreas M.,
Dastjerdi Mohammad,
Foster Brett L.,
Wandell Brian,
Parvizi Josef
Publication year - 2011
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1167.2011.03284.x
Subject(s) - lateralization of brain function , subdural space , epilepsy , neuroscience , audiology , stimulation , psychology , visual cortex , cortex (anatomy) , anatomy , medicine , surgery , hematoma
Summary Dual‐sided subdural electrodes are used in the localization and lateralization of seizure‐onset zones when the area of interest is within the interhemispheric fissure. We designed the current study to test the validity of the assumption that each side of the dual‐sided electrodes records from the hemisphere it faces. We recorded with dual‐sided strip and grid electrodes implanted in the occipital interhemispheric space in two patients with nonoccipital epilepsy during two visual stimulation tasks in which subjects were presented with visual stimuli in the ipsilateral or contralateral visual hemifields. Our findings show substantial contamination of recordings from the opposite hemisphere. Although, as expected, electrodes recording through the falx record faintly from the contralateral cortical surface, they unexpectedly pick up strong signals from the cortex behind them. Therefore, we conclude that these electrodes should not be used for lateralization of the origin of epileptic activity or evoked responses.