title: Contralateral dissociation between neural activity and cerebral blood volume during recurrent acute focal neocortical seizures.
abstract: OBJECTIVE
  Whether epileptic events disrupt normal neurovascular coupling mechanisms locally or remotely is unclear. We sought to investigate neurovascular coupling in an acute model of focal neocortical epilepsy, both within the seizure onset zone and in contralateral homotopic cortex.
  
  
  METHODS
  Neurovascular coupling in both ipsilateral and contralateral vibrissal cortices of the urethane-anesthetized rat were examined during recurrent 4-aminopyridine (4-AP, 15 mm, 1 μl) induced focal seizures. Local field potential (LFP) and multiunit spiking activity (MUA) were recorded via two bilaterally implanted 16-channel microelectrodes. Concurrent two-dimensional optical imaging spectroscopy was used to produce spatiotemporal maps of cerebral blood volume (CBV).
  
  
  RESULTS
  Recurrent acute seizures in right vibrissal cortex (RVC) produced robust ipsilateral increases in LFP and MUA activity, most prominently in layer 5, that were nonlinearly correlated to local increases in CBV. In contrast, contralateral left vibrissal cortex (LVC) exhibited relatively smaller nonlaminar specific increases in neural activity coupled with a decrease in CBV, suggestive of dissociation between neural and hemodynamic responses.
  
  
  CONCLUSIONS
  These findings provide insights into the impact of epileptic events on the neurovascular unit, and have important implications both for the interpretation of perfusion-based imaging signals in the disorder and understanding the widespread effects of epilepsy. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
authors: Department of Psychology, University of Sheffield, Sheffield, United Kingdom; Department of Neurological Surgery, Brain and Mind Research Institute, Brain and Spine Center, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York, U.S.A.
authors: Sam
authors: S
authors: Harris
authors: Luke
authors: L
authors: Boorman
authors: Michael
authors: M
authors: Bruyns-Haylett
authors: Aneurin
authors: A
authors: Kennerley
authors: Hongtao
authors: H
authors: Ma
authors: Mingrui
authors: M
authors: Zhao
authors: Paul G
authors: PG
authors: Overton
authors: Theodore H
authors: TH
authors: Schwartz
authors: Jason
authors: J
authors: Berwick
mesh_terms: D015761:4-Aminopyridine / Q000633:toxicity; D000818:Animals; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004195:Disease Models, Animal; D004569:Electroencephalography; D004827:Epilepsy / Q000139:chemically induced / Q000473:pathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D026902:Potassium Channel Blockers / Q000633:toxicity; D051381:Rats; D012008:Recurrence; D013003:Somatosensory Cortex / Q000503:physiopathology*; D018709:Statistics, Nonparametric
chemical_list: D026902:Potassium Channel Blockers; D015761:4-Aminopyridine
keywords: 4-Aminopyridine; Electrophysiology; Neurovascular coupling; Optical imaging spectroscopy