Coupling between gamma-band power and cerebral blood volume during recurrent acute neocortical seizures

Sam Harris, Hongtao Ma, Mingrui Zhao, Luke W Boorman, Ying Zheng, Aneurin Kennerley, Michael Bruyns-Haylett, Paul G Overton, Jason Berwick, Theodore H Schwartz

Research output: Contribution to journalArticlepeer-review

Abstract

Characterization of neural and hemodynamic biomarkers of epileptic activity that can be measured using non-invasive techniques is fundamental to the accurate identification of the epileptogenic zone (EZ) in the clinical setting. Recently, oscillations at gamma-band frequencies and above (>30 Hz) have been suggested to provide valuable localizing information of the EZ and track cortical activation associated with epileptogenic processes. Although a tight coupling between gamma-band activity and hemodynamic-based signals has been consistently demonstrated in non-pathological conditions, very little is known about whether such a relationship is maintained in epilepsy and the laminar etiology of these signals. Confirmation of this relationship may elucidate the underpinnings of perfusion-based signals in epilepsy and the potential value of localizing the EZ using hemodynamic correlates of pathological rhythms. Here, we use concurrent multi-depth electrophysiology and 2-dimensional optical imaging spectroscopy to examine the coupling between multi-band neural activity and cerebral blood volume (CBV) during recurrent acute focal neocortical seizures in the urethane-anesthetized rat. We show a powerful correlation between gamma-band power (25-90 Hz) and CBV across cortical laminae, in particular layer 5, and a close association between gamma measures and multi-unit activity (MUA). Our findings provide insights into the laminar electrophysiological basis of perfusion-based imaging signals in the epileptic state and may have implications for further research using non-invasive multi-modal techniques to localize epileptogenic tissue.

Original languageEnglish
Pages (from-to)62-70
Number of pages9
JournalNeuroimage
Volume97
Early online date13 Apr 2014
DOIs
Publication statusPublished - 15 Aug 2014

Keywords

  • 4-Aminopyridine
  • Animals
  • Blood Volume
  • Cerebrovascular Circulation
  • Convulsants
  • Electroencephalography
  • Female
  • Gamma Rhythm
  • Neocortex
  • Optical Imaging
  • Rats
  • Recurrence
  • Seizures
  • Journal Article
  • Research Support, Non-U.S. Gov't

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