unit 1 part 1

Psychoactive drugs

Chemicals that change consciousness, mood, perception, or behavior by affecting the nervous system.

Agonists

Drugs that increase a neurotransmitter's activity by mimicking it or enhancing its effects.

Antagonists

Drugs that block neurotransmitters from binding to receptors, reducing their effects.

Reuptake inhibitors

Drugs that prevent neurotransmitters from being reabsorbed, leaving more available in the synapse.

Stimulants

Drugs that increase activity in the central nervous system, increasing alertness and energy.

Caffeine

A stimulant found in coffee and tea that increases alertness by blocking adenosine receptors.

Cocaine

A powerful stimulant that increases dopamine activity by blocking its reuptake.

Depressants

Drugs that slow down activity in the central nervous system.

Alcohol

A depressant that slows brain activity, lowers inhibitions, and impairs judgment and coordination.

Hallucinogens

Drugs that alter perception and produce sensory experiences that are not actually occurring.

Marijuana

A drug from cannabis that can alter perception, mood, memory, and coordination.

Opioids

Drugs that relieve pain by binding to opioid receptors and can produce feelings of pleasure and relaxation.

Heroin

A highly addictive opioid that produces intense euphoria and pain relief.

Tolerance

The need for increasingly larger amounts of a drug to achieve the same effect.

Addiction

A compulsive pattern of drug use despite harmful consequences.

Withdrawal

Uncomfortable physical and psychological symptoms that occur when someone dependent on a drug stops using it.

Consciousness

Our awareness of ourselves and our environment.

Circadian rhythm (sleep/wake cycle)

The body's internal 24-hour biological clock that regulates sleep and wakefulness.

Jet lag

Disruption of the circadian rhythm caused by traveling across time zones.

Shift work

Working at times that conflict with the body's natural sleep-wake cycle.

NREM stage 1

The lightest stage of sleep; a transition between wakefulness and sleep.

Hypnagogic sensations

Vivid sensations that occur while falling asleep, such as feeling like you are falling.

NREM stage 2

A stage of light sleep characterized by sleep spindles and K-complexes.

NREM stage 3

The deepest stage of NREM sleep; important for physical restoration and growth.

REM sleep

A stage of sleep characterized by rapid eye movements, vivid dreams, and temporary muscle paralysis.

REM rebound

An increase in REM sleep after a period of REM sleep deprivation.

Activation-synthesis (dreams)

The theory that dreams happen when the brain tries to make sense of random neural activity during sleep.

Consolidation theory (dreams)

The theory that dreams help process and strengthen memories and experiences.

Memory consolidation

The process of stabilizing and storing new memories for long-term use.

Restoration of resources

The theory that sleep allows the body and brain to recover, repair, and restore energy.

Insomnia

A sleep disorder involving difficulty falling asleep, staying asleep, or getting restful sleep.

Narcolepsy

A sleep disorder involving sudden, uncontrollable episodes of falling asleep.

REM sleep behavior disorder

A disorder in which people physically act out their dreams because normal REM muscle paralysis is absent.

Sleep apnea

A disorder in which breathing repeatedly stops and starts during sleep.

Somnambulism

Sleepwalking; walking or performing activities while still asleep.

Sensation

The process of detecting physical stimuli from the environment through sensory receptors.

Transduction

The process of converting physical energy into neural signals that the brain can understand.

Perception

The process of organizing and interpreting sensory information to give it meaning.

Absolute threshold

The minimum stimulation needed to detect a stimulus 50% of the time.

Just-noticeable difference

The smallest difference between two stimuli that a person can detect 50% of the time.

Sensory adaptation

A decrease in sensitivity to an unchanging stimulus over time.

Weber's law

The principle that the just-noticeable difference is a constant proportion of the original stimulus.

Sensory interaction

The principle that one sense can influence another sense.

Synesthesia

A condition in which stimulation of one sense automatically triggers an experience in another sense.

Retina

The light-sensitive layer at the back of the eye containing rods and cones.

Blind spot

The area of the retina where the optic nerve exits; it contains no photoreceptors.

Visual nerve (optic nerve)

The nerve that carries visual information from the retina to the brain.

Lens

The clear structure in the eye that focuses light onto the retina.

Accommodation

The process of changing the shape of the lens to focus on objects at different distances.

Nearsightedness

An eye condition in which nearby objects are clear but distant objects appear blurry.

Farsightedness

An eye condition in which distant objects are clearer than nearby objects.

Photoreceptors

Light-sensitive cells in the retina that convert light into neural signals.

Rods

Photoreceptors that detect light and dark and help with vision in dim lighting; do not detect color.

Cones

Photoreceptors responsible for color vision and sharp detail; include sensitivity to red, green, and blue wavelengths.

Trichromatic theory

The theory that color vision comes from three types of cones sensitive to red, green, and blue wavelengths.

Opponent-process theory

The theory that color vision works through opposing pairs: red-green, blue-yellow, and black-white.

Fovea

The central area of the retina responsible for the sharpest and clearest vision.

Afterimages

Visual images that remain after looking away from an object, often caused by opponent-process activity.

Ganglion cells

Retinal cells that collect visual information and send it through the optic nerve to the brain.

Dichromatism

A form of color blindness in which a person has only two functioning types of color-sensitive cones.

Monochromatism

A rare condition in which a person has little or no color vision and sees mainly in shades of gray.

Prosopagnosia

Face blindness; difficulty recognizing familiar faces despite having normal vision.

Blindsight

The ability to respond to visual information without consciously seeing it.

Wavelength

The distance between two corresponding points of a wave; determines the hue of visible light.

Pitch

How high or low a sound is, determined by its frequency.

Amplitude

The height or strength of a sound wave; related to loudness.

Loudness

How loud or soft a sound seems, mainly determined by the sound wave's amplitude.

Pitch perception

The brain's interpretation of the frequency of sound waves as high or low sounds.

Place theory

The theory that different sound frequencies activate different locations along the cochlea's basilar membrane.

Volley theory

The theory that groups of neurons take turns firing to detect sound frequencies too high for one neuron to handle alone.

Frequency theory

The theory that pitch is determined by how frequently auditory neurons fire in response to a sound.

Sound localization

The ability to identify where a sound is coming from using differences in timing and loudness between the ears.

Conduction deafness

Hearing loss caused by problems transferring sound vibrations through the outer or middle ear.

Sensorineural deafness

Hearing loss caused by damage to the cochlea's hair cells or the auditory nerve.

Olfactory system

The sensory system responsible for detecting and processing smells.

Thalamus

The brain's sensory relay station that directs most sensory information to the appropriate brain areas; smell largely bypasses it.

Pheromones

Chemicals released by organisms that can influence the behavior or physiology of other members of the same species.

Gustation

The sense of taste.

Sweet, sour, salty, bitter, umami, oleogustus

The six taste qualities: sweet (sugars), sour (acids), salty (salts), bitter, umami (savory), and oleogustus (fatty taste).

Taste receptors

Sensory cells that detect chemicals in food and send taste information to the brain.

Supertasters

People who experience certain tastes, especially bitterness, more intensely.

Medium tasters

People with an average sensitivity to tastes.

Nontasters

People who experience certain tastes less intensely than average.