Unit 1 Psychology

absolute threshold

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

accommodation

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.

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.

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.

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.

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.

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.

corpus callosum

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

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.

Dopamine

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

electroencephalogram (EEG)

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

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.

epigenetics

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

eugenics

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

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.

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.

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.

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.

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.

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.

Inhibitory Neurotransmitter

A neurotransmitter that inhibits the firing of neurons.

interneurons

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

Jet Lag

A temporary sleep disorder that occurs when a person's internal body clock is out of sync with the time zone they are in.

Just Noticeable Difference (JND)

The minimum difference in stimulation that a person can detect 50% of the time.

kinesthesis

The sense of the body's position and movement of body parts relative to each other.

lesion

Damage to body tissue, often caused by disease or injury.

limbic system

A set of structures in the brain, including the amygdala, hypothalamus, and hippocampus, involved in emotion, motivation, and memory.

magnetic resonance imaging (MRI)

A technique that uses magnetic fields and radio waves to produce detailed images of the brain's soft tissue.

Marijuana

A drug containing THC that alters mood, perception, and cognitive function.

medulla

The base of the brainstem, controlling heartbeat and breathing.

Monochromatism

Complete color blindness where only shades of grey are perceived, with no ability to distinguish colors.

motor (efferent) neurons

Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

motor cortex

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

Multiple Sclerosis

A disease in which the immune system attacks the protective covering of nerves, leading to communication problems between the brain and the rest of the body.

Myasthenia Gravis

An autoimmune disorder that affects communication between nerves and muscles, leading to muscle weakness.

narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks, often triggered by strong emotions.

nature-nurture issue

The debate over the relative contributions of genetic inheritance and environmental factors to human development.

Nearsightedness (Myopia)

A condition where close objects are seen clearly, but distant objects are blurry.

nervous system

The body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

neuron

A nerve cell; the basic building block of the nervous system.

neuroplasticity

The brain's ability to reorganize itself by forming new neural connections throughout life, particularly in response to learning, experience, or injury.

neurotransmitters

Chemical messengers that transmit signals across the synaptic gap between neurons.

Norepinephrine

A neurotransmitter and hormone involved in arousal and alertness.

NREM sleep

Non-Rapid Eye Movement sleep; the sleep stages characterized by slow brain waves, relaxed muscles, and decreased heart rate and breathing.

occipital lobes

Regions of the cerebral cortex located at the back of the brain, responsible for processing visual information.

Oleogustus

A proposed sixth taste sensation for the taste of fat.

olfaction

The sense of smell.

opioids

A class of drugs that act on opioid receptors to produce morphine-like effects, including pain relief and feelings of euphoria.

opponent-process theory

A theory of color vision proposing that the brain processes color information in pairs of complementary colors (e.g., red-green, blue-yellow).

optic nerve

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

parasympathetic nervous system

The division of the autonomic nervous system that calms the body, conserving its energy and promoting rest and digestion.

parietal lobes

Regions of the cerebral cortex located at the top of the brain, responsible for processing sensory information such as touch and spatial awareness.

perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

peripheral nervous system

The sensory and motor neurons that connect the central nervous system to the rest of the body, transmitting information to and from the brain and spinal cord.

Pheromones

Chemicals secreted by animals that influence the behavior or physiology of others of the same species.

Pituitary Gland

The 'master gland' of the endocrine system that regulates other glands and controls various bodily functions.

place theory

The theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.

Plasticity

The brain's ability to change and adapt as a result of experience.