The effects of focal epileptic activity on regional sensory-evoked neurovascular coupling and postictal modulation of bilateral sensory processing

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

*Corresponding author for this work

Research output: Indexed journal article Articlepeer-review

15 Citations (Web of Science)

Abstract

While it is known that cortical sensory dysfunction may occur in focal neocortical epilepsy, it is unknown whether sensory-evoked neurovascular coupling is also disrupted during epileptiform activity. Addressing this open question may help to elucidate both the effects of focal neocortical epilepsy on sensory responses and the neurovascular characteristics of epileptogenic regions in sensory cortex. We therefore examined bilateral sensory-evoked neurovascular responses before, during, and after 4-aminopyridine (4-AP, 15 mmol/L, 1 μL) induced focal neocortical seizures in right vibrissal cortex of the rat. Stimulation consisted of electrical pulse trains (16 seconds, 5 Hz, 1.2 mA) presented to the mystacial pad. Consequent current-source density neural responses and epileptic activity in both cortices and across laminae were recorded via two 16-channel microelectrodes bilaterally implanted in vibrissal cortices. Concurrent two-dimensional optical imaging spectroscopy was used to produce spatiotemporal maps of total, oxy-, and deoxy-hemoglobin concentration. Compared with control, sensory-evoked neurovascular coupling was altered during ictal activity, but conserved postictally in both ipsilateral and contralateral vibrissal cortices, despite neurovascular responses being significantly reduced in the former, and enhanced in the latter. Our results provide insights into sensory-evoked neurovascular dynamics and coupling in epilepsy, and may have implications for the localization of epileptogenic foci and neighboring eloquent cortex.

Original languageEnglish
Pages (from-to)1595-1604
Number of pages10
JournalJournal of Cerebral Blood Flow and Metabolism
Volume33
Issue number10
DOIs
Publication statusPublished - Oct 2013
Externally publishedYes

Keywords

  • barrel cortex
  • electrophysiology
  • epilepsy
  • intrinsic optical imaging
  • neurovascular coupling

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