Electrical conductivities of the freshly excised cerebral cortex in epilepsy surgery patients; correlation with pathology, seizure duration, and diffusion tensor imaging

M. Akhtari, N. Salamon, R. Duncan, I. Fried, G. W. Mathern

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

The electrical conductivities (σ) of freshly excised neocortex and subcortical white matter were studied in the frequency range of physiological relevance for EEG (5-1005 Hz) in 21 patients (ages 0.67 to 55 years) undergoing epilepsy neurosurgery. Surgical patients were classified as having cortical dysplasia (CD) or non-CD pathologies. Diffusion tensor imaging (DTI) for apparent diffusion coefficient (ADC) and fractional anisotropy (FA) was obtained in 9 patients. Results found that electrical conductivities in freshly excised neocortex vary significantly from patient to patient (σ = 0.0660-0.156 S/m). Cerebral cortex from CD patients had increased conductivities compared with non-CD cases. In addition, longer seizure durations positively correlated with conductivities for CD tissue, while they negatively correlated for non-CD tissue. DTI ADC eigenvalues inversely correlated with electrical conductivity in CD and non-CD tissue. These results in a small initial cohort indicate that electrical conductivity of freshly excised neocortex from epilepsy surgery patients varies as a consequence of clinical variables, such as underlying pathology and seizure duration, and inversely correlates with DTI ADC values. Understanding how disease affects cortical electrical conductivity and ways to non-invasively measure it, perhaps through DTI, could enhance the ability to localize EEG dipoles and other relevant information in the treatment of epilepsy surgery patients.

Original languageEnglish
Pages (from-to)281-290
Number of pages10
JournalBrain Topography
Volume18
Issue number4
DOIs
StatePublished - Jun 2006

Keywords

  • Brain
  • Conductivity
  • Cortical dysplasia
  • DTI
  • EEG
  • MEG

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