Characterization of Large-Scale Functional Brain Networks During Ketamine-Medetomidine Anesthetic Induction
arXiv Preprint Archive – March 31, 2016
Source: arXiv
Summary
Scientists discovered that anesthesia dramatically alters brain network patterns in ways that help explain consciousness. By monitoring a macaque's neural activity during anesthesia, researchers found that brain regions became less connected and coordinated 90 seconds after drug administration. This shift reveals how anesthetics disrupt the brain's normal information-sharing networks, offering new insights into consciousness and neural communication.
Abstract
Several experiments provide evidence that specialized brain regions functionally interact and reveal that the brain processes and integrates information in a specific and structured manner. Networks can be applied to model brain functional activities, providing means to characterize and quantify this structured form of organization. Reports substantiate that different physiological states or diseases that affect the central nervous system may be associated with alterations in these networks, which might be reflected in graphs of different architectures. However, the relationship between their structure and the organism's distinct physiological conditions is poorly comprehended. Therefore, experiments that estimate the functional neural networks of subjects exposed to different controlled conditions are highly relevant. Within this context, this research has sought to model large-scale functional brain networks during an anesthetic induction process. The experiment was based on intra-cranial recordings of the neural activities of an old-world macaque of the species Macaca fuscata. Neural activity was recorded during a Ketamine-Medetomidine anesthetic induction process, and networks were estimated sequentially in five-second intervals. One and a half minutes after administering the anesthetics, changes occurred in various network properties, revealing a transition in the network architecture. During general anesthesia, functional connectivity and network integration capabilities were reduced at both local and global levels. Additionally, it has been verified that the brain shifted to a highly specific and dynamic state. The results provide empirical evidence and report the relationship between the induced state of anesthesia and functional network properties, contributing to the elucidation of novel aspects of the neural correlates of consciousness.