TY - JOUR T1 - Gamma Oscillations and Spontaneous Network Activity in the Hippocampus Are Highly Sensitive to Decreases in pO<sub>2</sub> and Concomitant Changes in Mitochondrial Redox State JF - The Journal of Neuroscience JO - J. Neurosci. SP - 1153 LP - 1162 DO - 10.1523/JNEUROSCI.4105-07.2008 VL - 28 IS - 5 AU - Christine Huchzermeyer AU - Klaus Albus AU - Hans-Jürgen Gabriel AU - Jakub Otáhal AU - Nando Taubenberger AU - Uwe Heinemann AU - Richard Kovács AU - Oliver Kann Y1 - 2008/01/30 UR - http://www.jneurosci.org/content/28/5/1153.abstract N2 - Gamma oscillations have been implicated in higher cognitive processes and might critically depend on proper mitochondrial function. Using electrophysiology, oxygen sensor microelectrode, and imaging techniques, we investigated the interactions of neuronal activity, interstitial pO2, and mitochondrial redox state [NAD(P)H and FAD (flavin adenine dinucleotide) fluorescence] in the CA3 subfield of organotypic hippocampal slice cultures. We find that gamma oscillations and spontaneous network activity decrease significantly at pO2 levels that do not affect neuronal population responses as elicited by moderate electrical stimuli. Moreover, pO2 and mitochondrial redox states are tightly coupled, and electrical stimuli reveal transient alterations of redox responses when pO2 decreases within the normoxic range. Finally, evoked redox responses are distinct in somatic and synaptic neuronal compartments and show different sensitivity to changes in pO2. We conclude that the threshold of interstitial pO2 for robust CA3 network activities and required mitochondrial function is clearly above the “critical” value, which causes spreading depression as a result of generalized energy failure. Our study highlights the importance of a functional understanding of mitochondria and their implications on activities of individual neurons and neuronal networks. ER -