How do general anaesthetics cause loss of consciousness Essay

How do general anaesthetics cause loss of consciousness - Essay Example Usually, the general anaesthetics are used during long surgical operations that are also very painful. For example, during hysterectomy, hernia repairs, removal of gall bladder and more (Perry 2010, p. 67). Positron Emission Tomography (PET) is one the research conducted in search for the effects of anaesthetics in humans.The PET study covers the activity of both inhibitory and excitatory neurons that describe the conscious states of mind (Alkire, Haier and Fallon 2000, p. 371). Other studies have identified that general anaesthetics affects the thalamus, cerebellum, midbrain reticular formation, occipital cortex and basal forebrain. Research has revealed that the anaesthetics suppress the thalamocortical circuits, which interfere with the transfer of signals across the neural networks (Squire 1996, p. 114). These agents thalamocortically suppresses the regions of the brain differently although some theories tend to assume that the agents affect the entire brain, mostly focusing on the midbrain reticular formation and thalamus. The general anaesthetics do not affect the brain activities the same way. They affect different regions of the brain thus producing different states of unconsciousness. While humans are asleep, the flow of blood in the thalamus reduces, which means low metabolic rates which lead to unconsciousness. On another hand, anaesthesia involves artificial suppression of the metabolism processes in the thalamus, which make human beings unconscious, as well. In their PET studies, Dr.Alkire, Fallon and Haier used 11 unconscious brains and 11 conscious brains. They used two anaesthetic agents, which include the isoflurane and the halo-thane. They recorded the regional uptakes of fluorodeoxyglucose (FDG) in each human brain of the subjects of the study. Then, they compared FDG uptake patterns of the unconscious subjects with the conscious subjects(Alkire, Haier and Fallon 2000, p.