The Role of Sleep in the Human Brain
Our biological clocks control many of our body’s functions, including learning, memory, and emotional states. During deep sleep, we reduce activity in certain areas of the brain that are linked to our decision-making and emotional processes. By allowing these areas to relax and rejuvenate, we may be able to maintain optimal levels of emotional and social functioning when awake. Recent research on the human brain has shown that there are repetitive nerve-signaling patterns that occur during deep sleep, which may help encode memories and enhance learning.
The circadian clock plays an important role in regulating sleep timing. Throughout the body, the clock combines signals from the environment with hormones to create an internal day-night rhythm. The purpose of the circadian system is to counteract the homeostatic drive to sleep during the day, and augment sleep at night. The circadian system is located in the suprachiasmatic nucleus of the brain, which is directly above the optic chiasm. Secondary clock systems are located throughout the body, including the eyes, ears, and mouth.
The three stages of sleep differ in their characteristics and the patterns of brain activity that occur during each stage. In the initial NREM stage, alpha activity is absent, and a low voltage mixed-frequency EEG pattern is followed by prominent theta and sharp waves. People in this stage of sleep may be easily roused and may experience sudden muscle contractions and falling. If the sleeper is unable to control his or her breathing, he or she may fall unconscious or suffer an injury.
Sleep has many other functions. It regulates our energy, metabolism, and thermoregulation, improves the immune system, and helps the brain develop and synaptically optimize. It has evolved in birds and has various mechanisms that control sleep onset, duration, and wakefulness. REM sleep is the most common type of sleep, whereas NREM sleep is the most common, and is also the most studied form of sleep. If you are having trouble determining which is which, consult a physician.
The REM phase of sleep is the final stage of sleep and the phase where dreams occur. During this stage, rapid eye movement, shallow breathing, and rapid heartbeat occur. REM sleep stimulates the learning and memory sections of the brain, and it occurs about 90 minutes into the cycle. In addition to regulating the length of the REM phase, the REM stage of sleep is important for maintaining good health and well-being. Depending on the stage of sleep, the duration of REM may vary from person to person.
There are two main types of sleep in humans. REM sleep is characterized by frequent bursts of eye movement, while NREM has less activity. While REM sleep is a paradoxical state of the same type as orthodox sleeping, both types are necessary for us to maintain a healthy lifestyle. For this reason, if you experience REM sleep, it is important to schedule it so you don’t miss the day. In addition, it is also important to monitor the timing of the sleep.