Sleep Disorders and Parasomnias

Chapter 44 Pt2

Narcolepsy

A sleep disorder associated with a loss of orexinergic neurons in the hypothalamus.

Orexinergic Neurons

Neurons located in the hypothalamus that produce orexin peptides, typically promoting wakefulness and repressing REM sleep.

Orexin Peptides

A type of peptide neurotransmitter that promotes wakefulness and is part of the arousal circuitry.

REM Behavior Sleep Disorder

A sleep disorder where normal motor paralysis during REM sleep is absent, leading individuals to act out their dreams.

Paralysis in REM sleep

A characteristic part of normal REM sleep involving activation of brainstem neurons and GABAergic output to the spinal cord, preventing motor function.

Link between REM Behavior Disorder and Parkinson's Disease

Individuals with REM behavior disorder are more likely to develop Parkinson's disease later on, often due to degeneration of brainstem neurons.

Non-REM Parasomnias

Sleep disorders that occur outside of the REM cycle, during phases N1 through N3 of sleep, such as sleepwalking, sleep talking, bedwetting, and night terrors.

Sleepwalking

A non-REM parasomnia where an individual, still asleep with their consciousness turned off, starts to wake up from deep sleep (N3) and has the ability to walk.

Sleep talking

A non-REM parasomnia where an individual talks during sleep, typically in non-REM phases, while not fully awake.

Night Terrors

A non-REM parasomnia, common in children under age 5, occurring in N3 sleep where children wake up screaming and thrashing, are inconsolable, still asleep, and have no memory of the event.

Sleep Paralysis

A phenomenon where an individual wakes up with their mind alert and eyes working, but their body remains paralyzed due to the REM circuitry keeping muscles still; often accompanied by fear and hallucinations.

Amygdala in Sleep Paralysis

Heightened activation of the fear circuitry in the amygdala during sleep paralysis, contributing to the strong fear response and the brain attempting to provide a reason for the fear through hallucinations.

Lucid Dreaming

A state during sleep where parts of consciousness awaken within the dream, allowing the individual to be aware they are dreaming and potentially control aspects of the dream.