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The Effects of Ketamine on the Brain’s Spontaneous Activity as Measured by Temporal Variability and Scale-Free Properties. A Resting-State fMRI Study in Healthy Adults.

Converging evidence from a variety of fields, including psychiatry, suggests that
the temporal correlates of the brain’s resting state could serve as essential markers of a
healthy and efficient brain. We use ketamine to induce schizophrenia-like states in 32
healthy individuals to examine the brain’s resting states using fMRI. We found a global
reduction in temporal variability quantified by the time series’ standard deviation and an
increase in scale-free properties quantified by the Hurst exponent representing the signal
self-affinity over time. We also found network-specific and frequency-specific effects of
ketamine on these temporal measures. Our results confirm prior studies in aging, sleep,
anesthesia, and psychiatry suggesting that increased self-affinity and decreased temporal
variability of the brain resting state could indicate a compromised and inefficient brain
state. Our results expand our systemic view of the temporal structure of the brain and
shed light on promising biomarkers in psychiatry

Identiferoai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/34105
Date January 2016
CreatorsAyad, Omar
ContributorsNorthoff, Georg
PublisherUniversité d'Ottawa / University of Ottawa
Source SetsUniversité d’Ottawa
LanguageEnglish
Detected LanguageEnglish
TypeThesis

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