Why Do We Dream? IPB University Neurologist Explains Four Types of Dreams Experienced by Humans during Sleep
Sleep is not just a break from daily activities, but a complex physiological process that is very important for the functioning of the body and brain. This was conveyed by IPB University Faculty of Medicine lecturer, dr Yeni Quinta Mondiani, SpN, in her statement about the dynamics of the nervous system during sleep.
“During sleep, there are fluctuating and dynamic changes in the nervous system, heart, lungs, and also the body’s metabolism,” said dr Yeni, who is also a specialist in neurology.
She added that sleep is a normal and recurrent physiological condition, characterized by a reversible decrease in consciousness. In this condition, cognitive function decreases globally so that the brain is unable to respond fully to surrounding stimuli.
Dr Yeni said that the sleep-wake cycle is controlled by a complex series of neural circuits and is divided into five main phases. Phases 1 to 4 are referred to as Non-Rapid Eye Movement (NREM), while the fifth phase is Rapid Eye Movement (REM).
“These five phases can repeat several times in one sleep period, and each has a specific physiological function,” she said.
She explained that the deepest sleep phase occurs in phases 3 and 4 of NREM. This phase functions to restore the body’s freshness and restore the body’s condition after activity, and has a high threshold for awakening.
“This phase is also often associated with sleep disorders such as sleepwalking and sleep terror,” she explains. Meanwhile, the REM phase is known as the phase when dreams usually occur and can be remembered clearly when awake.
Based on the results of research, continued dr Yeni, there are several areas of the brain that play an important role in the formation of dreams. One of them is the laterodorsal nucleus (LTD nuclei) in the medulla oblongata, which functions as a generator of REM cycles and gives rise to visual components in dreams and hallucinations.
“These LTD nuclei get input from the amygdala (emotional center) and hippocampus (memory center), which explains why dreams are emotional and imprinted in memory,” she explains.
In addition, research from the University of Wisconsin-Madison identified another important area, the posterior cortical hot zone, which shows high electrical activity when a person is dreaming. This area is likened to the projection screen of a brain movie, which shows a combination of human emotions, memories, and desires.
Not only that, the prefrontal cortex, the part of the brain that functions in logical thinking, is also said to be active during sleep. “The more active this part is, the more likely we are to remember the contents of the dream,” explained dr Yeni.
She concluded that there are specific brain regions that are needed to produce conscious experiences such as dreams. Until now, there are still many theories about the function of dreams and REM sleep.
“Some argue that dreams help the brain store memories, others say that dreams function to forget things that are not important or as a form of brain reset,” she explained.
Furthermore, dr Yeni said that there are more psychological theories. For example, dreams as a form of wish fulfillment that is not achieved in the real world.
“In dreams, we are always present as the main character, and there is always a setting. It’s like constant training for the brain to feel ‘I exist’, ‘I am different from the world around me’,” she said.
Interestingly, said dr Yeni, “Because we forget most of our dreams, the brain is not too busy having to store all the strange experiences from the dream. So we can learn and develop without being too burdened.”
More in-depth, she also classifies the types of dreams as follows:
- Standard dreams, occurring about 4-6 times a night, mostly in the REM phase. Generally visual, influenced by daily activities or stress, usually remembered vividly when awake.
- Nightmares, full of fear or panic, often waking up in an anxious state. Triggered by stress, anxiety, sleep disorders or other mental health conditions.
- Night terrors. In contrast to dreams, this is a non-REM sleep disorder, usually experienced by children. Suddenly waking up, screaming, confused, but usually not remembering the dream.
- Lucid dreaming. The dreamer is aware that they are dreaming; sometimes they can control the course of the dream. Often occurs in the REM phase, and can be used for therapy, for example to overcome nightmares. (dr) (IAAS/PRO)
