  Anesthetic agents are neurotropic drugs capable of inducing significant
alterations in the thalamocortical system, promoting a profound decrease in
awareness and level of consciousness. There is experimental evidence that
general anesthesia affects large-scale functional networks, leading to
alterations in the brain's state. However, the specific impact on the network
structure assumed by functional connectivity locally in different cortical
regions has not yet been reported. Within this context, the present study has
sought to characterize the functional brain networks relative to the frontal,
parietal, temporal, and occipital lobes. In this study, electrophysiological
neural activity was recorded using a dense ECoG-electrode array placed directly
on the cortical surface of an old-world monkey of the species Macaca fuscata.
Networks were estimated serially over time every five seconds, while the animal
model was under controlled experimental conditions of a Ketamine-Medetomidine
anesthetic induction. In each of the four cortical brain lobes, noticeable
alterations in distinct properties of the networks evidenced a transition in
the network's architecture, which occurred within approximately one and a half
minutes after administering the anesthetics. The characterization of functional
brain networks performed in this study provides relevant experimental evidence
that expands our understanding of the neural correlates of consciousness in
terms of the structure and properties of the functional brain networks.
