Home > Sleep paralysis

1 Normal sleep paralysis

Normal sleep paralysis is thought to be due to mechanisms in the brain stem, particularly the reticular, vestibular, and oculomotor neurons, which prevent bodily movements, block sensory input and provide the forebrain with the internally generated activity that characterises brain activity during REM sleep. This is thought to be necessary to prevent the body from movements caused by dreams. Eyes however are not paralyzed by this system, and this exception was used to prove that lucid dreaming was an objectively verifiable phenomenon.

2 Awareness during sleep paralysis

The Nightmare , by Henry Fuseli ( 1781) is thought to be one of the classic depictions of awareness during sleep paralysis perceived as a demonic visitation.

The disorder known as "sleep paralysis" occurs when the brain is awakened from a REM state into essentially a normal fully awake state, but with the bodily paralysis still occurring. This causes the person to be fully aware, but unable to move. In addition, this state is usually accompanied by certain specific kinds of hallucinations. This state usually lasts no more than two minutes before a person is able to either return to full REM sleep or to become fully awake.

2.1 Accompanying hallucinations

Many report hallucinations during these episodes. The features of these hallucinations generally vary by individual, but some are more common to the experience than others:

Most common

• Vividness
• Fear

Common

• Sensing a "presence" (often malevolent )
• Pressure/weight on body (especially the chest)

Fairly common

• Auditory hallucinations (often footsteps or indistinct voices)
• Visual hallucinations (often related to the forementioned "presence"; in these cases, sometimes nebulous )

Less common

• Floating sensation (sometimes associated with out-of-body experiences)

Rare

• Falling sensation
• Vibration

2.2 Possible causes

Little is known about the physiology of awareness during sleep paralysis. However, some have suggested that it may be linked to post synaptic inhibition of motor neurons in the pons region of the brainFor other articles about other subjects named brain see brain (disambiguation). In the anatomy of animals, the brain or encephalon is the supervisory center of the nervous system. Although the brain is usually cited as the supervisory center of vertebrate. In particular, low levels of melatoninMelatonin or 5-methoxy-N- acetyl tryptamine, is a hormone produced by pinealocytes in the pineal gland, located in the center of the brain. It is a derivative of the amino acid tryptophan. Melatonin helps regulate sleep-wake or circadian rhythms. Normally may stop the depolarisation current in the nerves, which prevents the stimulation of the muscles.

There is also a significant positive correlation between those experiencing this disorder frequently and those suffering from narcolepsyNarcolepsy is a neurological condition characterized by irresistible episodes of sleep and general sleep disorder. It is a kind of dyssomnia. Symptoms of narcolepsy The main characteristic of narcolepsy is overwhelming excessive daytime sleepiness (EDS),. However, various studies suggest that many or most people will experience sleep paralysis at least once or twice in their lives.

Some report that various factors increase the likelihood of both paralysis and hallucinations. These include:

• Sleeping in a supine position
• Irregular sleeping schedules; naps, sleeping in
• Increased stress
• Sudden environmental/lifestyle changes