The Science of Dreaming

Image via Time

Humans dream for about 20% of the time they spend sleeping; this period of sleep is known as REM (rapid eye movement) sleep.  Once someone awakes, they will only remember what they dreamt if the woke up during the REM stage because dreams are not stored in the short term memory. Once one awakes, the dream no longer makes logical sense. This is because the neurotransmitters, such as serotonin, become active once the individual awakes, and these are what allow the brain to rationalize. During this REM sleep, the cortex of the brain is in an awake like state. Although it seems to the dreamer that he or she is awake, they are not capable of moving because the top of the spinal cord which is connected to the brain stem prevents the instructions for muscle movement from reaching the brain. The brain requires sleep so that it can produce cells to replace the ones that have been used during the day. Dreaming is essential for the brain to repair, so it will incorporate external noises into the dream so as to give the brain uninterrupted time to produce new cells. Many scientists theorize that dreaming is a result of evolution. Quite often when mammals dream, they place themselves in threatening situations. Scientist explain this by indicating that this prepares them to navigate a similar situation if it were to happen. Because of this, dreaming makes an organism more fit.  Overall, dreams are simply chemical reactions and random nerve signals, which the brain either interprets as a dream or uses to recall a memory.