An experimental model to evaluate the whole-brain neuro-vascular coupling

Zahiu D (1), Calin A (1), Acatrinei C (1), Mirica S (1), Gonzalez A (1), Paslaru A (1), Zagrean AM (1), Moldovan M (1,2) and Zagrean L (1) 1Division of Physiology and Fundamental Neuroscience, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; 2Neuroscience and Pharmacology, Panum, University of Copenhagen, Copenhagen, Denmark

Romanian Society of Physiology Meeting 2013, Iasi – Romania, May 9-11, 2013
Friday, May 10, 2013

Introduction A transient increase in cortical neuronal activity results in a transient increase in cerebral blood flow. This physiological neurovascular coupling is used to infer neuronal activity in vascular-based modern functional brain imaging techniques. Nevertheless, brain pathology may interfere with the process of neurovascular coupling confounding the interpretation of imaging studies. We propose a novel method to evaluate the state of neurovascular coupling at the whole brain level: by using deep general anesthesia to induce a burst-suppression (BS) electroencephalographic (EEG) activity, activity-dependent hemodynamic changes could be measured by burst-triggered averaging.
Methods BS was induced by chloral hydrate overdose, at a BS ratio of 50-75%, in adult male Wistar rats. The rectified fronto-occiptal EEG (rEEG) was used to identify the burst onset used for averaging the laser Doppler (LD) signal from the frontal cortex.
Results We found that following burst onset there was an increase in LD that peaked within seconds after the rEEG peak, consistent with a neurovascular response.
Conclusion Our study provides proof of concept that whole-brain neurovascular coupling can be evaluated during spontaneous cerebral activity by inducing a safely reversible anesthetic BS state. This could amend the design of clinical neurovascular coupling studies.