The Physiology of Sleep
During sleep, the thalamus transmits sensory information to the cerebral cortex, which interprets information from short-term memory to long-term storage. During most stages of sleep, the thalamus is quiet, but during the REM stage of sleep, it becomes active and is responsible for sending sensory information to the cortex. Sleep also helps the brain maintain emotional stability by increasing the activity in areas responsible for emotion regulation, including the amygdala (located in the temporal lobe).
Physiological factors are not the only ways to define sleep. Several criteria, including sensory, motor, and behavioral characteristics, can help define sleep. While some criteria are absent in certain types of sleep, such as wakefulness and sleepwalking, the general consensus among observers makes discrimination between sleep and wakefulness relatively easy. As such, it is important to understand the physiological processes associated with each stage. While these factors may differ in some cases, sleep is the most commonly experienced phase of human life.
The physiological requirements for sleep are similar among various species. There is a relaxation of skeletal muscles and lack of goal-directed behaviour. The characteristic posture of sleep in humans and other animals is that of horizontal repose, which implies a passive role towards the environment. Sleepwalking, on the other hand, raises questions about the capacity of the human brain. This may be true for humans but marine mammals appear to be asleep only half of the time.
In humans, sleep drive plays a key role in controlling when you wake up and sleep. Sleep drive builds throughout the day, but it reaches a critical point when the body cannot resist it. While a person cannot force himself to eat during the day, it can force himself to sleep if he is tired. In a similar manner, microsleeping may occur when someone is extremely tired and unable to sleep. It is important to get plenty of sleep to maintain optimal health.
Research on the physiological aspects of sleep in animals has paved the way for more detailed studies. The EEG, a form of externally measurable sleep, provides information about the brain’s activities. Such studies may eventually allow scientists to identify specific brain structures that mediate sleep and determine their functional roles in the process. The study of sleep also makes it possible to monitor the physiological conditions that promote sleep. So far, there is little doubt that the REM phase of sleep is important for maintaining the body’s health.
Sleep quality is just as important as the quantity of sleep you get. For example, if you get interrupted sleep, you are not likely to get the full eight hours of sleep you need to function properly. Consequently, you might find it difficult to wake up in the morning or focus during the day. You may even find yourself drifting off throughout the day. If these habits are the problem, you may need to seek treatment for your underlying condition.