Individualized localization and cortical surface-based registration of intracranial electrodes

Andrew R. Dykstra, Alexander M. Chan, Brian T. Quinn, Rodrigo Zepeda, Corey J. Keller, Justine Cormier, Joseph R. Madsen, Emad N. Eskandar, Sydney S. Cash

Research output: Contribution to journalArticlepeer-review

168 Scopus citations


In addition to its widespread clinical use, the intracranial electroencephalogram (iEEG) is increasingly being employed as a tool to map the neural correlates of normal cognitive function as well as for developing neuroprosthetics. Despite recent advances, and unlike other established brain-mapping modalities (e.g. functional MRI, magneto- and electroencephalography), registering the iEEG with respect to neuroanatomy in individuals-and coregistering functional results across subjects-remains a significant challenge. Here we describe a method which coregisters high-resolution preoperative MRI with postoperative computerized tomography (CT) for the purpose of individualized functional mapping of both normal and pathological (e.g., interictal discharges and seizures) brain activity. Our method accurately (within 3. mm, on average) localizes electrodes with respect to an individual's neuroanatomy. Furthermore, we outline a principled procedure for either volumetric or surface-based group analyses. We demonstrate our method in five patients with medically-intractable epilepsy undergoing invasive monitoring of the seizure focus prior to its surgical removal. The straight-forward application of this procedure to all types of intracranial electrodes, robustness to deformations in both skull and brain, and the ability to compare electrode locations across groups of patients makes this procedure an important tool for basic scientists as well as clinicians.

Original languageEnglish (US)
Pages (from-to)3563-3570
Number of pages8
Issue number4
StatePublished - Feb 15 2012
Externally publishedYes


  • CT
  • Electrocorticography
  • Epilepsy
  • Image registration
  • MRI

ASJC Scopus subject areas

  • Neurology
  • Cognitive Neuroscience


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