Mapping oxygen concentration in the awake mouse brain

Abstract
Article and author information
Metrics

Abstract

Although critical for brain function, the physiological values of cerebral oxygen concentration have remained elusive because high-resolution measurements have only been performed during anesthesia, which affects two major parameters modulating tissue oxygenation: neuronal activity and blood flow. Using measurements of capillary erythrocyte-associated transients, fluctuations of oxygen partial pressure (Po₂) associated with individual erythrocytes, to infer Po₂ in the nearby neuropil, we report the first non-invasive micron-scale mapping of cerebral Po₂ in awake, resting mice. Interstitial Po₂ has similar values in the olfactory bulb glomerular layer and the somatosensory cortex, whereas there are large capillary hematocrit and erythrocyte flux differences. Awake tissue Po₂ is about half that under isoflurane anesthesia, and within the cortex, vascular and interstitial Po₂ values display layer-specific differences which dramatically contrast with those recorded under anesthesia. Our findings emphasize the importance of measuring energy parameters non-invasively in physiological conditions to precisely quantify and model brain metabolism.

Article and author information

Author details

Declan G Lyons

Laboratory of Neurophysiology and New Microscopies,, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, Paris, France

Competing interests
The authors declare that no competing interests exist.
Alexandre Parpaleix

Laboratory of Neurophysiology and New Microscopies,, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, Paris, France

Competing interests
The authors declare that no competing interests exist.
Morgane Roche

Laboratory of Neurophysiology and New Microscopies,, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, Paris, France

Competing interests
The authors declare that no competing interests exist.
Serge Charpak

Laboratory of Neurophysiology and New Microscopies,, Institut National de la Santé et de la Recherche Médicale, Université Paris Descartes, Paris, France

For correspondence
serge.charpak@parisdescartes.fr

Competing interests
The authors declare that no competing interests exist.

Ethics

Animal experimentation: All animal care and experimentation was performed in accordance with the INSERM Animal Care and Use Committee guidelines (protocole number CEEA34.SC.122.12 and CEEA34.SC.123.12)

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.