The Dream: a complex psychological phenomenon

A dream is an altered state of consciousness that occurs during sleep. It is often accompanied by images, sounds, emotions, and sensations that can seem very real. Dreams intrigue, worry, and fascinate. When do they occur? What happens in the brain when we dream? Can we control the content of our dreams? Do they have a connection to our own lives? What is their significance? These are questions that have fascinated scientists, psychologists, and philosophers for centuries.

Dreams mainly occur during the REM (Rapid Eye Movement) sleep phase. This is the final phase of the sleep cycle characterized by rapid eye movements, lack of muscle tone, irregular breathing, and heart rate. EEGs (Electroencephalograms) reveal that the brain's electrical activity during REM sleep is close to that of wakefulness. Dreams also occur during non-REM sleep, but these dreams are shorter, less complex, and less emotionally charged than those during REM sleep.

A night consists of three to six successive sleep cycles, each lasting 90 to 120 minutes. These cycles comprise five stages during which the body and brain function differently. REM sleep is the fifth and final stage, occurring roughly 90 minutes after falling asleep and repeating multiple times throughout the night. The duration of dreams increases as the night progresses. The first dream lasts about ten minutes, the second about twenty, while subsequent dreams can last up to half an hour. These later dreams are the ones remembered most vividly since they occur toward the end of the night.

Advancements in brain imaging have aided in understanding the neurophysiological mechanisms at play during dreams. Four areas of the brain particularly activate during REM sleep:

- Visual-spatial regions (located at the back of the brain) produce images.

- The motor cortex simulates movements.

- The hippocampus, associated with autobiographical memory.

- The amygdala and cingulate cortex, deep emotional centers related to emotion management.

Other brain regions remain notably inactive. Specifically, the prefrontal cortex, responsible for rational ideas and logical decision-making, is "asleep" during REM sleep. This could explain why our dreams are often illogical, incoherent, or impossible.

Do dreams have a biological and psychological function? Currently, there isn’t sufficient scientific evidence to provide a unanimous answer to this question. However, several hypotheses have been proposed:

- Dreams are a state of the brain, much like sleep and wakefulness. It would be the result of neurological reprogramming to preserve individuals' memory and personality (Payne and al, 2004).

- Dreams could be essential in helping us manage emotions experienced during the day, acting as a regulator for our emotional balance. Without dreams, we might be overwhelmed by our emotions.

- Dreams might be a voluntary act, a means of solving problems or healing psychological wounds. This theory emphasizes "lucid dreaming," where individuals can control their dreams.

- Dreams might be random neuronal activations in our brain. At night, our brain continues to process information received during the day and reacts to external stimuli during sleep. However, because it's not fully alert, the scenarios playing in our minds are not always coherent.

- Dreams might be a manifestation of repressed desires that appear in an imaginative way. This could be a message from our subconscious. Dreams allow us to "talk" to different aspects of ourselves, especially those we are unfamiliar with. According to psychiatrist Carl Gustav Jung, this dialogue helps us progress in life through a better understanding of ourselves.

Dreams, as a complex psychological phenomenon, have intrigued humanity for centuries. Advances in brain imaging have revealed specific brain activity during dreams, activating areas associated with visualization, memory, emotions, and motor simulation. Yet, the profound meaning of dreams remains elusive, giving rise to various theories and hypotheses. Some envision an emotional regulation function, while others see them as reflections of our unconscious desires. Ongoing research encourages further exploration of this mysterious territory of our minds, where reality blends with imagination, and science meets human intuition. Current studies pave the way for new perspectives, gradually shedding light on the enigma that is the dream, a phenomenon both intimate and universal, offering a mirror to our deepest thoughts, emotions, and aspirations.