CBSE Class 10 Answered
It is unknown where in the brain dreams originate, if there is a single origin for dreams or if multiple portions of the brain are involved, or what the purpose of dreaming is for the body or mind. Several studies point to the involvement of brain stem in dreams. According to certain scientists, dream images are instigated by random signals shooting up from the brain stem to the visual cortex and other parts of the forebrain.
There are basically two main schools of thought on why we dream - physiological theory and psychological theory.
Both theories agree that we dream during the REM, or rapid eye movement, phase of sleep. During this phase of sleep, our closed eyes dart rapidly about, our brain activity peaks, and our muscles suffer temporary paralysis.
The physiological theory centers upon how our body, specifically our brains, function during the REM phase of sleep. Proponents of this theory believe that we dream to exercise the synapses, or pathways, between brain cells, and that dreaming takes over where the active and awake brain leaves off. When awake, our brains constantly transmit and receive messages, which course through our billions of brain cells to their appropriate destinations, and keep our bodies in perpetual motion. Dreams replace this function.
Psychologically - There are many worries from work and problems unsolved that are left over from the day. Dreams help providing spaces for yourself to obtain a calm and peaceful mind, in preparation for facing other troubles in real life. They may also act as forerunners for any surprising incidents that one may or may or expect later on