The parts of the brain responsible for awareness-the ability to think and perceive-are the neurons (brain cells) in the cortex (grey matter) of the two hemispheres and the axons (communicating projections) in the white matter between those neurons. Roberts examined him for either spontaneous eye opening or eye opening in response to painful stimuli. To determine if Matt was capable of wakefulness, Dr. This is much like a computer-if the power supply does not provide electricity to the computer, the computer will not function. As a result, the brain is not “turned on” and cannot support awareness. Clinically, if the RAS is not functioning normally, then the patient is incapable of becoming conscious and the eyes will not open-even in response to painful stimuli (such as pinching the clavicle or pressing a knuckle into the sternum). In other words, eye opening alone is not sufficient to indicate that a person is conscious. However, although wakefulness is necessary for consciousness, wakefulness alone is insufficient for consciousness. Therefore, spontaneous eye opening or eye opening in response to stimuli is a reliable sign that the RAS is functioning and that wakefulness is present. (See image below) When the RAS stimulates the brain, a person’s eyes open. The part of the brain responsible for wakefulness is the reticular activating system (RAS), a collection of neurons in the upper brainstem that send widespread stimulatory projections to the areas of the brain responsible for awareness. Roberts first had to determine whether Matt’s brain was capable of wakefulness, and then she would look for signs of awareness. The neurons and their circuits (connections) that support wakefulness are in one region of the brain, and the neurons and circuits that provide awareness are in other regions of the brain. Both must be present for consciousness to be present. Neurologists divide consciousness into two components: wakefulness and awareness. She was concerned with assessing the function of the parts of the brain that are responsible for consciousness so that she could determine if Matt was aware of anything and if he was capable of suffering. Roberts was not concerned with the notoriously thorny philosophical problems of defining consciousness. A Working Definition of Consciousness: Simultaneous Wakefulness and Awareness In the following report, we present two possible scenarios, discuss how doctors answer these questions, and define the terms: wakefulness, awareness, consciousness, coma, vegetative state, minimally conscious state, and brain death. (Note: Matt is not a real patient, but a realistic composite of many patients for whom we have cared.) Roberts if Matt was conscious or unconscious and whether he was likely to recover. Therefore, it was clear that Matt had sustained severe brain damage that was causing severely impaired consciousness-i.e., coma. A review of Matt’s medications and the lab and toxicology tests showed the presence of no substances that might worsen Matt’s neurologic exam. When she held his eyes open, no spontaneous eye movements were evident, nor did he look at her face. Roberts shouted Matt’s name and applied painful stimuli to assess his level of consciousness, his eyes did not open. When blood was drawn from his arm, he did not move it or even wince. Matt was still in the bed and didn’t move spontaneously. He received treatments, such as medications to elevate blood pressure, ventilator support of breathing, and IV fluids for hydration, all of which are necessary to support the brain and the body so that the brain can recover from injury.Īlthough Matt’s vital organs were not seriously injured, a CT scan showed widespread swelling of the brain. They placed an endotracheal (breathing) tube in his trachea (windpipe) and transported him to the hospital, where he was admitted to the ICU. Approximately five minutes after a terrible car accident that ejected Matt Trenton from his car, first responders found him face down and not breathing.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |