Impaired reactivity of burst-suppression EEG patterns following transient global cerebral ischemia in rat

Alexandru Stoian (1), Alexandru Calin (2), Denise Zahiu (1), Alexandru-Catalin Paslaru (1), Mihai Stancu (1), Camelia Acatrinei (1), Andrei Ilie (2), Ana-Maria Zagrean (1), Leon Zagrean (1), Mihai Moldovan (1,3) 1) Division of Physiology and Fundamental Neuroscience, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; 2) Oxford University, Oxford, United Kingdom; 3) Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark

9th FENS Forum of Neuroscience 2014
Session: C23 - Abstract Number: FENS-2267 - Poster Board Number: C077
July 5 - July 9, Milan, IT


Global cerebral ischemia, such as occurs during cardiac arrest, is often associated with suppression of electrocortical activity, neuronal damage and poor neurological recovery. EEG monitoring has revealed that early after an ischemic episode, the electrocortical activity resumes through a sequence of "bursts" of activity alternating with periods of electrical "suppression", the post-ischemic burst-suppression (BS) pattern. In some cases, the BS patterns are reactive to external stimuli, which can trigger bursts and reorganize the BS patterns. We investigated the reactivity of BS patterns following 1, 3, 5, and 10 minutes of transient global cerebral ischemia (GCI) by 4-vessel occlusion in adult male Wistar rats under chloral-hydrate anesthesia. BS patterns were recorded from occipital cortex by implanted epidural electrodes. Super-bright LED flashes were delivered every 2 seconds to one eye. Given the predominantly crossed visual projection in rats, the ipsilateral occipital recording was uncontaminated by the visual evoked responses, and could be used to quantify the BS patterns. During reperfusion following GCI, the amplitude of the visual evoked potential (VEP) recovered prior to onset of the EEG bursting activity. Following unlesional GCIs of 1 and 3 minutes, most of the early EEG bursts started within 500ms after the flash-induced VEPs, although not all flashes were able to trigger bursts. For GCIs longer than 3 minutes, the BS reactivity was impaired, although the VEPs amplitude appeared unaffected. This study raises the hope that measures of BS reactivity can be used to derive early prognostic markers for comatose patients following cerebral ischemia.

Student Alexandru Stoian was awarded the prize of the National Neuroscience Society of Romania, consisting in partial travel support to attend FENS Forum 2014.