A study led by the Massachusetts Institute of Technology (MIT) has shown that the frequency of electrical waves communicating between several key areas within the brain is significantly altered when anesthetic drugs are in effect. The findings mean that it is possible to visualize whether a patient is safely anesthetized using electroencephalography (EEG) equipment in the operating room, anesthesiologists say.
The study used animal brains to observe how a common general anesthetic drug, isoproterenol (Propofol), actually affects the brain causing the organism to lose consciousness.
People take for granted that anesthetics simply ‘turn off’ the brain, and our study shows that isoproterenol significantly alters the band used to communicate between brain regions,” said Earl Miller, a professor of neurology and one of the principal investigators. “
Many functions related to consciousness, such as vision and judgment, rely on coordinated cooperation between various areas of the brain in order to accomplish them. Communication between the thalamus, a region located deeper in the brain, and the cerebral cortex is one of those important types of cooperation. Researchers found that they must communicate through various bands of frequencies between 4 and 100 hertz.
This study found that in the presence of the anesthetic isoproterenol, the frequency used for communication between several areas of the thalamus and cortex was reduced to approximately only 1 Hz. In this state, the organism manifests as unconsciousness.
Co-investigator Emery N. Brown, an anesthesiologist at Massachusetts General Hospital, said that the frequency used for communication between regions of the brain is visible through EEG equipment, which is generally available in operating rooms. The study’s findings mean that by viewing the EEG, anesthesiologists can visualize the state of a patient being anesthetized: when the anesthetic takes effect and the surgeon can begin to operate safely, and when the effects of the drug wear off and the patient begins to regain consciousness. “With this method anesthesiologists can take better care of their patients.” Brown said.
Not only that, but the team also found that stimulating the thalamus region with a high-frequency current (180 Hz) counteracted the effects of isoproterenol. “This stimulation produced a restorative effect on consciousness, with increased activity in the cerebral cortex and decreased intensity of low-frequency communication,” the study said.
The study was published April 27 in the journal eLife.
Recent Comments