AP Psychology-Unit 1: Biological Bases

absolute threshold

absolute threshold

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

accomodation

In vision, the process by which the lens of the eye shifts to focus on a particular object.

acetylcholine

A neurotransmitter involved in muscle activation, memory, and learning.

action potential

A brief electrical charge that travels down the axon of a neuron, generated by the movement of positively charged atoms in and out of channels in the neuron's membrane.

Activation-Synthesis Theory

A theory of dreaming that suggests dreams are the brain's attempt to make sense of random neural activity.

addiction

A complex condition characterized by compulsive drug use or behaviors despite harmful consequences.

agonist

A drug or chemical that enhances the activity of neurotransmitters.

Alcohol

A depressant that slows down the central nervous system, impairing cognitive and motor functions.

all-or-none response

The principle that a neuron either fires completely or does not fire at all.

alpha waves

The relatively slow brain waves associated with relaxation and wakefulness.

Amplitude

The height of a wave, which determines the loudness of a sound.

amygdala

A limbic system structure involved in processing emotions, particularly fear and aggression.

antagonist

A drug or chemical that inhibits or blocks the action of neurotransmitters.

Aphasia

A condition characterized by the loss of ability to understand or express speech.

association areas

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

audition

The sense of hearing.

Auditory Cortex

The part of the brain that processes auditory information.

autonomic nervous system

The part of the peripheral nervous system that controls involuntary functions like heart rate, digestion, and glandular secretion.

axon

The extension of a neuron through which neural impulses are sent.

barbiturates

A class of drugs that depress the activity of the central nervous system, reducing anxiety but impairing memory and judgment.

behavior genetics

The study of the relative power and limits of genetic and environmental influences on behavior.

biological psychology

A branch of psychology concerned with the links between biology and behavior.

biopsychosocial approach

An integrated approach that incorporates biological, psychological, and social-cultural levels of analysis.

blind spot

The point at which the optic nerve leaves the eye, creating a small gap in the field of vision.

blindsight

A condition in which a person can respond to visual stimuli without consciously experiencing them.

bottom-up processing

Analysis that begins with sensory receptors and works up to the brain's integration of sensory information.

brainstem

The oldest part and central core of the brain, responsible for automatic survival functions.

Broca's Area

A region in the frontal lobe of the brain associated with speech production.

Caffeine

A stimulant found in coffee, tea, and many soft drinks that increases alertness and reduces fatigue.

central nervous system

The brain and spinal cord, responsible for processing and coordinating information.

cerebellum

A structure in the hindbrain that helps coordinate voluntary movement and balance.

cerebral cortex

The outer layer of the brain responsible for complex cognitive processes such as thinking, planning, and language.

Charles Darwin

An English naturalist who proposed the theory of evolution by natural selection.

circadian rhythm

The biological clock; regular bodily rhythms that occur on a 24-hour cycle.

Cocaine

A powerful stimulant drug that increases levels of dopamine in the brain, leading to intense euphoria and increased energy.

cochlea

A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses.

cochlear implant

A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.

cognitive neuroscience

The interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory, and language).

computed tomography (CT)

A scanning technique using multiple X-rays to construct a 3D image of the brain's structure.

conduction hearing loss

Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.

cones

Photoreceptor cells in the retina that are responsible for color vision and fine detail.

consciousness

Our awareness of ourselves and our environment.

Consolidation Theory

The theory that sleep helps strengthen the neural connections that form our memories.

Contralateral Control

The principle that each hemisphere of the brain controls the opposite side of the body.

cornea

The transparent outer layer of the eye that covers the pupil and iris and helps focus incoming light.

corpus callosum

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

David Hubel

A Canadian neurophysiologist known for his work with Torsten Wiesel on the processing of visual information in the brain.

delta waves

The large, slow brain waves associated with deep sleep.

dendrites

Branchlike extensions of a neuron that receive messages and conduct impulses toward the cell body.

Depolarization

The process by which a neuron's membrane potential becomes less negative, leading to the firing of an action potential.

depressants

Drugs that reduce neural activity and slow body functions.

Dichromatism

A type of color blindness where one of the three basic color mechanisms is absent or not functioning.

difference threshold

The minimum difference between two stimuli required for detection 50% of the time; also known as just noticeable difference (JND).

Dopamine

A neurotransmitter involved in reward, motivation, and motor control.

dream

A sequence of images, emotions, and thoughts passing through a sleeping person's mind.

dual processing

The idea that information is simultaneously processed on separate conscious and unconscious tracks.

electroencephalogram (EEG)

A recording of the electrical waves sweeping across the brain's surface, measured by electrodes placed on the scalp.

embodied cognition

The theory that cognition is influenced by the body's interactions with the environment.

endocrine system

The body's "slow" chemical communication system, consisting of glands that secrete hormones into the bloodstream.

endorphins

Neurotransmitters that are natural painkillers produced by the brain.

environment

Every nongenetic influence, from prenatal nutrition to the people and things around us.

epigenetics

The study of environmental influences on gene expression that occur without a DNA change.

Ernst Weber

A German physician credited with the formulation of Weber's law, which describes the relationship between the magnitude of a physical stimulus and the intensity of its perceived sensation.

eugenics

A controversial and unethical movement aimed at improving the genetic quality of the human population.

evolutionary psychology

The study of the evolution of behavior and the mind, using principles of natural selection.

Excitatory Neurotransmitter

A neurotransmitter that promotes the firing of neurons.

Farsightedness (Hyperopia)

A condition where distant objects can be seen clearly, but close objects appear blurry.

feature detectors

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.

fMRI

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

forebrain

The largest and most prominent part of the brain, including the cerebral cortex and subcortical structures.

fovea

The central focal point in the retina, around which the eye's cones cluster.

fraternal (dizygotic) twins

Twins who develop from separate eggs and are no more similar genetically than non-twin siblings.

frequency

The number of complete wavelengths that pass a point in a given time.

frequency theory

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.

frontal lobes

The portion of the cerebral cortex lying just behind the forehead, involved in planning and judgment.

GABA (Gamma-Aminobutyric Acid)

The main inhibitory neurotransmitter in the brain.

Ganglion Cells

Neurons in the retina that relay information from the photoreceptors to the brain.

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.

genes

The biochemical units of heredity that make up the chromosomes; a segment of DNA capable of synthesizing a protein.

genome

The complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes.

glial cells

Cells in the nervous system that support, nourish, and protect neurons, and play a role in learning and thinking.

Glutamate

The main excitatory neurotransmitter in the brain.

gustation

The sense of taste.

Gustav Fechner

A German psychologist known for his work in psychophysics, particularly his development of Weber's law and the concept of the just noticeable difference.

hallucinations

Perceptions that have no direct external cause, arising from disorders such as schizophrenia, sensory deprivation, or drug-induced states.

hallucinogens

Drugs that alter perception and cause hallucinations or profound distortions in a person's perceptions of reality.

heredity

The genetic transmission of characteristics from parents to offspring.

Heroin

An opioid drug that produces intense euphoria and pain relief, highly addictive.

hindbrain

The lower part of the brainstem, comprising the medulla, pons, and cerebellum, responsible for basic life functions.

hippocampus

A neural center located in the limbic system that helps process explicit memories for storage.

hormones

Chemical messengers produced by the endocrine glands and circulated in the bloodstream, regulating the activity of target cells or organs.

hue

The dimension of color that is determined by the wavelength of light; what we know as the color names blue, green, etc.

hypnagogic sensations

Sensations experienced during the transition from wakefulness to sleep, including hallucinations, muscle jerks, and sensations of falling.

hypothalamus

A neural structure lying below the thalamus, regulating bodily functions such as hunger, thirst, body temperature, and sexual behavior, and controlling the pituitary gland.

identical (monozygotic) twins

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms.

Inhibitory Neurotransmitter

A neurotransmitter that inhibits the firing of neurons.

inner ear

The innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs, involved in balance and hearing.

insomnia

Persistent problems falling asleep or staying asleep.

intensity

The amount of energy in a light or sound wave, which we perceive as brightness or loudness.

interneurons

Neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs.