Neuroscience and Sleep Disorders: Brain Structures, Functions, and REM Sleep

Brain Plasticity

The brain's ability to change, especially during childhood, by reorganizing damage or building new pathways.

Corpus Callosum

The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.

REM

Recurring sleep stage during which vivid dreams commonly occur; muscles relaxed but other systems active.

fMRI

A technique for revealing blood flow and brain activity by comparing successive MRI scans. Shows function and structure.

Broca's Area

Area of the frontal lobe that directs muscle movements involved in speech; helps control language expression.

REM rebound

The tendency for REM sleep to increase following REM sleep deprivation.

Lesions

Tissue destruction, naturally or experimentally caused destruction of brain tissue.

Wernicke's Area

Brain area involved in language comprehension and expression.

Activation Synthesis theory

A theory that explains dreams as the brain's interpretation of random neural activity.

Brain Stem

The oldest part and central core of the brain beginning where the spinal cord swells entering the skull.

Somnambulism

A sleep disorder characterized by complex motor activity during NREM sleep; sleepwalking.

Consolidation theory

A theory suggesting people sleep to process information acquired during the day.

Cerebellum

"Little brain" at rear of brain stem; processes sensory input, coordinates movement and balance, enables nonverbal learning.

Aphasia

Impairment of language, usually caused by damage to Broca's or Wernicke's area in the left hemisphere.

Insomnia

Recurring problems in falling or staying asleep.

Cerebral cortex

The intricate fabric of interconnected neural cells covering the cerebral hemispheres.

Consciousness

Our subjective awareness of ourselves and our environment.

Narcolepsy

Sleep disorder where uncontrollable sleep attacks occur; lapsing into REM sleep at inopportune times.

Limbic System

Neural system below cerebral hemispheres associated with emotions, memories, and drives.

Circadian rhythm

Our biological clock regulating sleep-wake cycles.

REM sleep behavior disorder

Sleep disorder involving motor activity during REM sleep, often enacting dream sequences.

Thalamus

Brain's sensory control center on top of brain stem; directs sensory messages to cortex and replies to cerebellum and medulla.

Hypnagogic sensations

Bizarre experiences like jerking or feeling of falling while transitioning to sleep.

Sleep apnea

Sleep disorder with temporary cessations of breathing and repeated momentary awakenings.

NREM

Non-rapid eye movement sleep; encompasses all sleep stages except REM.