Unit 1.2 Vocabulary - Biological Bases of Behavior: Psychoactive Drugs, Consciousness, Sleep, & Sensation

Flashcards covering key terms related to biological bases of behavior, psychoactive drugs, consciousness, sleep, and sensation.

Psychoactive drug

A chemical substance that alters the brain, causing changes in perceptions & moods

Substance use disorder

A disorder characterized by continued substance use despite resulting life disruption

Depressants

Drugs that reduce neural activity & slow body functions

Tolerance

The diminishing effect with regular use of the same dose of a drug, requiring the user to take larger & larger doses before experiencing the drug’s effect

Addiction

An everyday term for compulsive substance use (& sometimes for dysfunctional behavior patterns, such as out-of-control gambling) that continues despite harmful consequences

Withdrawal

The discomfort & distress that follow discontinuing an addictive drug or behavior

Barbiturates

Drugs that depress CNS activity, reducing anxiety but impairing memory & judgment

Opioids

Opium & its derivatives; they depress neural activity, temporarily lessening pain & anxiety

Stimulants

Drugs that excite neural activity & speed up body functions

Hallucinogens

Psychedelic (“mind-manifesting”) drugs that distort perceptions & evoke sensory images in the absence of sensory input

Consciousness

Our subjective awareness of ourselves & our environment

Cognitive neuroscience

The interdisciplinary study of the brain activity linked with cognition (thinking, knowing, remembering, & communicating)

Blindsight

A condition in which a person can respond to a visual stimulus without consciously experiencing it

Sleep

A periodic, natural loss of consciousness - as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation

Circadian rhythm

Our biological clock; regular bodily rhythms (for example, of temperature & wakefulness) that occur on a 24-hour cycle

REM sleep

Rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur; also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active (sometimes called R sleep)

Alpha waves

Relatively slow brain waves of a relaxed, awake state

NREM sleep

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

Hallucinations

False sensory experiences, such as seeing something in the absence of an external visual stimulus

Hypnagogic sensations

Bizarre experiences, such as jerking or feeling of falling or floating weightlessly, while transitioning to sleep (also called hypnic sensations)

Delta waves

Large, slow brain waves associated with deep sleep

Suprachiasmatic nucleus (SCN)

A pair of cell clusters in the hypothalamus that controls circadian rhythm; in response to light, the SCN adjusts melatonin production, thus modifying our feelings of sleepiness

Insomnia

Recurring problems in falling or staying asleep

Narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks; the affected person may lapse directly into REM sleep, often at inopportune times

Sleep apnea

A sleep disorder characterized by temporary cessations of breathing during during sleep & repeated momentary awakenings

REM sleep behavior disorder

A sleep disorder in which normal REM paralysis does not occur; instead, twitching, talking, or even kicking or punching may occur, often acting out one’s dream

Somnambulism

Sleep disorder that causes people to move around or perform unexpected activities while sleeping (also known as sleepwalking)

Dream

A sequence of images, emotions, & thoughts passing through a sleeping person’s mind

REM rebound

The tendency for REM sleep to increase following REM sleep deprivation

Sensation

The process by which our sensory receptors & nervous system receive & represent stimulus energies from our environment

Sensory receptors

Sensory nerve endings that respond to stimuli

Perception

The process by which our brain organizes & interprets sensory information, enabling us to recognize objects & events as meaningful

Bottom-up processing

Information processing that begins with the sensory receptors & works up to the brain’s integration of sensory information

Top-down processing

Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience & expectations

Transduction

Conversion or one form of energy into another; in sensation, the transforming of physical energy, such as sights, sounds, & smells, into neural impulses

Absolute threshold

The minimum stimulus energy needed to detect a particular stimulus 50% of the time

Difference threshold

The minimum difference between two stimuli required for detection 50% of the time; we experience the difference threshold as a just noticeable difference (jnd)

Weber’s law

The principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount)

Sensory adaptation

Diminished sensitivity as a consequence of constant stimulation

Wavelength

The distance from the peak of one light wave or sound wave to the peak of the next; electromagnetic wavelengths vary from the short gamma waves to the long pulses of radio transmission

Cornea

The eye’s clear, protective outer layer, covering the pupil & iris

Pupil

The adjustable opening in the center of the eye through which light enters

Iris

A ring of muscle tissue that forms the colored portion of the eye around the pupil & controls the size of the pupil opening

Lens

The transparent structure behind the pupil that changes shape to help focus images on the retina

Retina

The light-sensitive back inner surface of the eye, containing the receptor rods & cones plus the layers of neurons that begin the processing of visual information

Accommodation

The process by which the eye’s lens changes shape to focus images of near or far objects on the retina

Rods

Retinal receptors that detect black, white, & gray, & are sensitive to movement; rods are necessary for peripheral & twilight vision, when cones don’t respond

Cones

Retinal receptors that are concentrated near the center of the retina & that function in daylight or in well-lit conditions; cones detect fine detail & give rise to color sensations

Optic nerve

The nerve that carries neural impulses from the eye to the brain

Blind spot

The point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there

Fovea

The central focal point in the retina, around which the eye’s cone cluster

Young-Helmholtz trichromatic (three-color) theory

The theory that the retina contains 3 different types of color receptors - one most sensitive to red, one to green, & one to blue - which, when stimulated in combination, can produce the perception of any color

Opponent-process theory

The theory that opposing retinal processes (red-green, blue-yellow, white-black) enable color vision; for example, some cells are stimulated by green & inhibited by red; others are stimulated by red & inhibited by green

Feature detectors

Nerve cells in the brain’s visual cortex that respond to specific features of the stimulus, such as shape, angle, or movement

Dichromatism

Color-blindness in which only only two of the three primary colors can be discerned

Monochromatism

Complete color-blindness in which all colors appear as shades of one color

Prosopagnosia

“Face blindness”; a cognitive disorder of face perception in which the ability to recognize familiar faces, including one’s own face, is impaired, while other aspects of visual processing & intellectual functioning remain intact

Audition

The sense or act of hearing

Frequency

The number of complete wavelengths that pass a point in a given time (for example, per second); produces pitch

Amplitude

Loudness of a sound

Middle ear

The chamber between the eardrum & the cochlea containing 3 tiny bones that concentrate the vibrations of the eardrum on the cochlea’s oval window

Cochlea

A coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses

Inner ear

The innermost part of the ear, containing the cochlea, semicircular canals, & vestibular sacs

Sensorineural deafness

The most common form of hearing loss, caused by damage to the cochlea’s receptor cells or to the auditory nerve; also called nerve deafness

Conduction deafness

A less common form of hearing loss, caused by damage to the mechanical system that conducts sound waves to the cochlea

Place theory

In hearing, the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated (also called place coding)

Frequency theory

In hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch (also called temporal coding)

Volley theory

In hearing, the theory that neurons alternate firing in rapid succession, allowing us to hear frequencies above 1000 waves per second

Gate-control theory

The theory that the spinal cord contains a neurological “gate” that blocks pain signals or allows them to pass on to the brain; the “gate” is opened by the activity of pain signals traveling up small nerve fibers, & is closed by activity in larger fibers or by information coming from the brain

Gustation

Our sense of taste

Olfaction

Our sense of smell

Kinesthesis

Our movement sense; our system for sensing the position & movement of individual body parts

Vestibular sense

Our balance sense; our sense of body movement & position that enables our sense of balance

Sensory interaction

The principle that one sense can influence another, when the smell of food influences taste

Intensity

Amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness; intensity is determined by the wave’s amplitude