Dreams are successions of images, ideas, emotions, and sensations that occur involuntarily in the mind during certain stages of sleep. The scientific study of dreams is called oneirology. Scientists believe that, in addition to humans, birds and other mammals also dream.
Dreams mainly occur in the rapid-eye movement (REM) stage of sleep-when brain activity is high and resembles that of being awake. REM sleep is revealed by continuous movements of the eyes during sleep. Dreams can last for a few seconds, or as long as twenty minutes. Each of us averages four to seven a night. We spend 1.5 hours or more - about 20 per cent of our sleep time - in dreaming.
Now we came to know what are dreams and its duration,
But ….
Did anybody thought about chemistry behind the dreams?
How different kind of chemicals/hormones effect dreams?
All dreams, nightmares and night terrors are all caused by different chemicals being released while you are sleeping. The way you fall asleep is through the activation of the neurotransmitter gamma-aminobutyric acid (GABA).
Sleeping is considered as a default state in us but you can’t sleep when ever you required. There are two reasons behind this is
One reason is your body will not support when your brain is active
Second reason is secretion of Acetylcholine and other chemicals in our body which will makes us awaken throughout the day.
Acetylcholine is released in high levels as a result of wakefulness and alertness. But it is also found in high levels during REM sleep. Its lowest levels have been found during delta sleep.
Other chemicals which make us awaken during day time are
- Dopamine
- Glutamate
- Aspartate
- Histamine
- Serotonin
- Norepinephrine
At the end of the day Acetylcholine and other chemicals makes us tired and from this time to until before you are going to sleep there is a raise in levels of chemical called Melatonin.
Melatonin
Melatonin is a natural hormone made by your body's pineal gland. Pineal gland is located just above the middle of the brain. Melatonin levels in the blood stay elevated for about 12 hours - all through the night - before the light of a new day when they fall back to low daytime levels by about 9 am. Daytime levels of melatonin are barely detectable.
Melatonin is sometimes called "the hormone of the night."
Melatonin might help shift workers on irregular shifts who need to adjust their schedules. When taken in low doses at the appropriate time, melatonin can help advance or delay the sleep-wake cycle. The effect can last for six hours.
Some researchers have suggested that at certain doses, melatonin increases the number of dreams a person remembers by artificially prolonging the amount of time spent in REM sleep. Taking melatonin may also increase a person’s chances of experiencing a lucid dream for a similar reason, by elevating them to a more self-aware state while they are still in REM sleep.
Oxytocin
Oxytocin is a mammalian neurohypophysial hormone that acts primarily as a neuromodulator in the brain. It is once released in the body, effects sleep processes. Levels of oxytocin peak after 5 hours of sleep.
Oxytocin levels are also correlated with stages of light sleep (State II of sleeping). Dreams from State II are just as filled with social interactions as dreams from REM sleep.
According to scientists oxytocin affects our social emotions in real life, and the same thing will continues in sleep.
Adenosine is a purine nucleoside comprising a molecule of adenine attached to a ribose sugar molecule (ribofuranose) moiety via a β-N9-glycosidic bond.
Adenosine appears to accumulate in your bloodstream when you're awake and eventually makes you drowsy. Inside your brain, your adenosine levels exert a major influence on the regulation of non-REM sleep. This regulating effect occurs when an enzyme called adenosine deaminase breaks down, or metabolizes, adenosine molecules.
The rate of this metabolism has an effect on the intensity and duration of sleep when slow brain waves are present. Metabolism also reduces your brain's adenosine supplies, and your adenosine levels drop as sleep continues.
Although so many chemicals will affect our sleep and dreams in spite of all these we may forget many of our dreams! But how?
We forget almost all dreams soon after waking up as dreams tend to burst apart quickly. Dreams involve a low-grade type of mental activity, using brain mechanisms much like those used by the drunk and drugged.
Some of the research works states that delay in awakening a dreamer even just five minutes after the end of the eye movements, the chances of dream recall are greatly reduced. After other five or ten minutes, there's very little chance at all of recall.
One of the unexplained theories says that lack of hormone called nor-epinephrine in the cerebral cortex is responsible for forgetting dreams after awakening.
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