Unit 1: Biological Bases of Behavior

Transduction

The process of converting sensory stimuli into neural impulses.

Sensory Adaptation

Reduced sensitivity to a stimulus after prolonged exposure.

Cocktail Party Effect

The ability to focus on one voice among many.

Synesthesia

A condition where stimulation of one sense triggers another.

Prosopagnosia

The inability to recognize faces, often due to brain damage.

Wavelengths

The distance between peaks in a wave, affecting color in vision and pitch in hearing.

Accommodation

The process by which the lens changes shape to focus images on the retina.

Lens

The transparent structure behind the pupil that focuses light onto the retina.

Nearsightedness (Myopia)

A condition where distant objects appear blurry because light is focused in front of the retina.

Farsightedness (Hyperopia)

A condition where nearby objects appear blurry because light is focused behind the retina.

Retina

The light-sensitive layer at the back of the eye containing photoreceptors.

Thalamus

The brain’s sensory relay station; directs sensory signals to the appropriate cortical areas.

Photoreceptors

Cells in the retina that detect light, including cones and rods.

Cones

Photoreceptors responsible for color vision and fine detail.

Rods

Photoreceptors responsible for black-and-white vision and night vision.

Ganglion Cells

Neurons in the retina that transmit visual information to the brain.

Blind Spot

The point where the optic nerve leaves the eye, lacking photoreceptors.

Trichromatic Theory

The theory that color vision is based on three types of cones detecting red, green, and blue.

Afterimages

Visual illusions that persist after the original stimulus is removed.

Dichromatism

Color blindness where one type of cone is missing.

Monochromatism

Complete color blindness due to a lack of functioning cones.

Opponent-Process Theory

The theory that color perception is controlled by opposing retinal processes.

Amplitude (Vision & Hearing)

The height of a wave; determines brightness in vision and loudness in hearing.

Frequency

The number of waves passing a point per second; determines pitch in hearing.

Loudness

Perceived volume of sound, related to amplitude.

Pitch

The perceived highness or lowness of a sound, related to frequency.

Sound Localization

The ability to determine the source of a sound.

Place Theory

The idea that pitch is determined by where in the cochlea hair cells respond.

Conduction Deafness

Hearing loss due to damage in the mechanical parts of the ear.

Nerve (Sensorineural) Deafness

Hearing loss due to damage to hair cells or the auditory nerve.

Gate Control Theory

The idea that pain signals can be blocked by competing stimuli or endorphins.

Taste Receptors

Sensory cells responsible for detecting taste.

Supertasters

People with a higher-than-average number of taste buds, making them more sensitive to flavors.

Nontasters

People with fewer taste buds, leading to less sensitivity to taste.

Medium Tasters

People with a moderate number of taste buds.

Semicircular Canals

Structures in the inner ear involved in balance.

Kinesthesis

The sense that detects body position and movement.

Gustation

The sense of taste.

Olfaction

The sense of smell.

Vestibular Sense

The sense of balance, controlled by the inner ear.

Sweet

A taste sensation often associated with energy-rich foods.

Sour

A taste associated with acidic foods.

Salty

A taste related to sodium intake.

Bitter

A taste often associated with potentially toxic substances.

Umami

A savory taste associated with amino acids.

Oleogustus

The taste of fat.

Priming

Exposure to one stimulus influences response to a later stimulus.

Blind Sight

The ability to respond to visual stimuli without conscious awareness.

Consciousness

Awareness of self and surroundings.

Psychoactive Drugs

Substances that alter brain chemistry and perception.

Agonists

Drugs that mimic neurotransmitters.

Antagonists

Drugs that block neurotransmitters.

Reuptake

The process of reabsorbing neurotransmitters into the presynaptic neuron.

Tolerance

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

Withdrawal

Unpleasant symptoms when a drug is discontinued.

Caffeine

A stimulant that blocks adenosine receptors.

Cocaine

A stimulant that increases dopamine levels.

Stimulants

Drugs that increase nervous system activity.

Alcohol

A depressant that slows brain function.

Depressants

Drugs that slow the nervous system.

Hallucinogens

Drugs that alter perception.

Marijuana

A drug affecting perception and memory.

Opiates

Drugs that relieve pain and elevate mood.

Heroin

A powerful opiate that mimics endorphins.

Circadian Rhythm

The body’s internal clock.

NREM Stage 1

Light sleep with theta waves.

NREM Stage 2

Sleep spindles appear.

NREM Stage 3

Deep sleep with delta waves.

Restoration of Resources

The body replenishes energy during sleep.

REM Sleep

Dreaming occurs; brain activity resembles wakefulness.

Paradoxical Sleep

Another name for REM sleep.

REM Rebound

Increased REM sleep after deprivation.

Insomnia

Difficulty falling or staying asleep.

Narcolepsy

Sudden sleep attacks.

Sleep Apnea

Breathing stops during sleep.

Somnambulism

Sleepwalking.

Activation-Synthesis Theory

Dreams are the brain’s attempt to make sense of random activity.

Consolidation Theory

Dreams help process and store memories.

Genetic Predisposition

Increased likelihood of traits due to genetics.

Neurons

Nerve cells.

Multiple Sclerosis

A disease that damages the myelin sheath.

Neural Transmission

The process of nerve signal transmission.

Resting Potential

A neuron’s inactive state.

Threshold

The level needed to trigger an action potential.

Action Potential

The electrical signal sent down an axon.

All-or-None Principle

A neuron either fires completely or not at all.

Depolarization

The process during action potential when positive ions rush into the neuron.

Excitatory Neurotransmitters

Chemicals that increase the likelihood of a neuron firing.

Inhibitory Neurotransmitters

Chemicals that decrease the likelihood of a neuron firing.

Dopamine

A neurotransmitter involved in movement, pleasure, and motivation.

Serotonin

A neurotransmitter involved in mood regulation.

Norepinephrine

A neurotransmitter that controls alertness and arousal.

Glutamate

The brain’s primary excitatory neurotransmitter.

GABA (Gamma-Aminobutyric Acid)

The brain’s main inhibitory neurotransmitter.

Endorphins

Natural painkillers produced by the body.

Substance P

A neurotransmitter responsible for transmitting pain signals to the brain.

Acetylcholine (ACh)

A neurotransmitter involved in muscle contraction and memory.

Alzheimer’s Disease

A degenerative brain disorder associated with memory loss.

Myasthenia Gravis

A disorder that causes muscle weakness due to problems with acetylcholine receptors.

Sensory Neurons (Afferent Neurons)

Neurons that carry information from the senses to the brain.