Neuroscience and Sleep: Brain Structures, Functions, and Disorders

Motor Cortex

Cerebral cortex area at the rear of the frontal lobes that controls voluntary movements.

Somatosensory Cortex

Cerebral cortex at the front of the parietal lobes that registers and processes body touch and movement sensations.

Association Areas

Areas of the cerebral cortex that are not involved in primary motor or sensory functions such as learning, remembering, thinking.

Split Brain

Condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers connecting them.

Corpus Callosum

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

Consciousness

Subjective awareness of ourselves and our environment.

Circadian Rhythm

Our biological clock that occurs during the 24-hour cycle.

REM Sleep

Rapid eye movement sleep, a recurring sleep stage during which vivid dreams commonly occur, also known as paradoxical sleep.

Hypnagogic Sensations

Bizarre experiences, such as jerking or a feeling of falling or floating weightlessly, while transitioning to sleep.

Amygdala

Two lima-bean-sized neural clusters in the limbic system; linked to emotion.

Hypothalamus

Neural structure lying below the thalamus; directs several maintenance activities, helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.

Hippocampus

Neural campus located in the limbic system; helps process explicit memories for storage.

Cerebral Cortex

Intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.

Frontal Lobe

Portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans/judgments.

Parietal Lobes

Portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.

Occipital Lobes

Portion of the cerebral cortex lying at the back of the head; receives information from the visual field.

Temporal Lobes

Portion of the cerebral cortex lying roughly above the ears; includes auditory areas, each of which receives info primarily from the opposite ear, enables language processing.

Insomnia

Recurring problems in falling or staying asleep.

Narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks; affected people may lapse into REM sleep.

Sleep Apnea

Sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.

REM Sleep Behavior Disorder

Sleep disorder in which normal REM paralysis doesn't occur; instead, twitching, talking, or even kicking/punching may occur, often acting out one's dream.

Somnambulism

Sleepwalking or sleeptalking.

REM Rebound

Tendency for REM sleep to increase following REM sleep deprivation.

Lesion

Tissue destruction; a naturally or experimentally caused destruction of brain tissue.

Electroencephalogram

An amplified recording of the waves of electrical activity sweeping across the brain's surfaces, measured by electrodes on the scalp.

fMRI

Technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans.

Brainstem

Oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; responsible for automatic survival functions.

Medulla

Base of the brainstem; controls heartbeat and breathing.

Thalamus

Brain's sensory control center, located on top of the brainstem; directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.

Reticular Formation

A nerve network that travels through the brainstem and thalamus and plays an important role in controlling arousal.

Cerebellum

The little brain at the rear of the brainstem; functions include processing sensory input, coordinating movement output and balance, and enabling learning/movement.

Limbic System

Neural system located below the cerebral hemispheres; associated with emotions/drives.