| Term | Definition |
|---|---|
| adoption studies | A research method that compares adopted children to their biological and adoptive parents to determine the effects of genes and environment on behavior and mental processes. |
| environment | External factors that one experiences, such as family interactions or education; also referred to as 'nurture.' |
| eugenics | A discriminatory application of evolutionary principles that seeks to improve human populations through selective breeding or genetic manipulation. |
| evolutionary perspective | A theoretical approach that explores how natural selection affects the expression of behavior and mental processes to increase survival and reproductive success. |
| family studies | A research method that examines similarities in traits and behaviors among family members to determine the effects of heredity and environment. |
| heredity | Genetic or predisposed characteristics that influence physical, behavioral, and mental traits and processes; also referred to as 'nature.' |
| natural selection | The process by which traits that increase survival and reproductive success become more common in a population over time. |
| twin studies | A research method that compares similarities and differences between identical and fraternal twins to determine the effects of genes on behavior and mental processes. |
| Term | Definition |
|---|---|
| autonomic nervous system | The division of the peripheral nervous system that governs involuntary processes such as heart rate and digestion. |
| brain | The central organ of the central nervous system that processes information and controls body functions. |
| central nervous system | The part of the nervous system consisting of the brain and spinal cord that processes information and coordinates responses. |
| parasympathetic nervous system | The division of the autonomic nervous system responsible for the 'rest and digest' response that helps reduce anxiety and promote relaxation. |
| peripheral nervous system | The part of the nervous system outside the brain and spinal cord that connects the central nervous system to the rest of the body. |
| somatic nervous system | The division of the peripheral nervous system that governs voluntary processes and skeletal muscle control. |
| spinal cord | The bundle of nerves extending from the brain through the vertebral column that is part of the central nervous system. |
| sympathetic nervous system | The division of the autonomic nervous system responsible for the 'fight or flight' response that contributes to feelings of anxiety. |
| Term | Definition |
|---|---|
| acetylcholine | A neurotransmitter involved in muscle movement, learning, and memory. |
| action potential | A rapid change in a neuron's membrane potential that allows it to transmit signals over long distances. |
| addiction | A compulsive pattern of psychoactive drug use that can create significant withdrawal symptoms when the drug is no longer consumed. |
| adrenaline | A hormone involved in the stress response, increasing heart rate and arousal. |
| agonists | Psychoactive drugs that bind to receptors and encourage neural firing by mimicking or enhancing neurotransmitter effects. |
| all-or-nothing principle | The rule that a neuron either fires completely or does not fire at all; there is no partial firing of an action potential. |
| antagonists | Psychoactive drugs that bind to receptors and discourage neural firing by blocking neurotransmitter effects. |
| central nervous system | The part of the nervous system consisting of the brain and spinal cord that processes information and coordinates responses. |
| depolarization | The process by which a neuron's membrane potential becomes less negative, moving toward or past zero, triggering an action potential. |
| depressants | Psychoactive drugs such as alcohol that typically decrease neural activity and slow down the central nervous system. |
| dopamine | A neurotransmitter involved in reward, motivation, movement, and mood regulation. |
| endorphins | Neurotransmitters involved in pain relief and the experience of pleasure. |
| excitatory message | A neurotransmitter signal that makes an action potential more likely by depolarizing the receiving neuron. |
| GABA | An inhibitory neurotransmitter that reduces neural activity and promotes relaxation. |
| ghrelin | A hormone that increases appetite and signals hunger to the brain, primarily produced in the stomach. |
| glial cells | Cells in the nervous system that provide structure, insulation, communication, and waste transport to support neural function. |
| glutamate | An excitatory neurotransmitter involved in learning and memory. |
| hallucinogens | Psychoactive drugs such as marijuana that typically cause distortions in perception and/or cognition. |
| hormone | A chemical messenger released into the bloodstream that affects behavior and mental processes similar to neurotransmitters. |
| inhibitory message | A neurotransmitter signal that makes an action potential less likely by hyperpolarizing the receiving neuron. |
| interneurons | Neurons in the central nervous system that connect sensory and motor neurons and process information between them. |
| leptin | A hormone that decreases appetite and signals satiety (fullness) to the brain, produced by fat cells. |
| melatonin | A hormone that regulates sleep-wake cycles and circadian rhythms. |
| motor neurons | Neurons that transmit signals from the central nervous system to muscles to produce movement and behavior. |
| neural transmission | The process by which neurons communicate through the release and reception of neurotransmitters across synapses. |
| neurons | Neural cells that transmit information throughout the nervous system and are responsible for behavior and mental processes. |
| neurotransmitter | A chemical messenger released by neurons that transmits signals across synapses to affect the activity of other neurons or cells. |
| neurotransmitter function | The process by which neurotransmitters transmit signals between neurons and affect neural communication. |
| norepinephrine | A neurotransmitter involved in arousal, attention, and the stress response. |
| opioids | Psychoactive drugs such as heroin that typically act as pain relievers by affecting pain perception. |
| oxytocin | A hormone involved in social bonding, trust, and reproductive behaviors. |
| peripheral nervous system | The part of the nervous system outside the brain and spinal cord that connects the central nervous system to the rest of the body. |
| psychoactive drugs | Substances that alter brain chemistry and affect behavior, mental processes, and consciousness. |
| reflex arc | A neural pathway in the spinal cord that enables rapid, automatic responses to stimuli without requiring brain involvement. |
| refractory period | A period of time after an action potential during which a neuron cannot fire again, either absolutely (no new action potential possible) or relatively (only with stronger stimulation). |
| resting potential | The stable negative electrical charge of a neuron at rest, typically around -70 millivolts. |
| reuptake | The process by which neurotransmitters are removed from the synaptic cleft and reabsorbed by the presynaptic neuron. |
| reuptake inhibitors | Psychoactive drugs that block the reabsorption of neurotransmitters back into the presynaptic cell, prolonging their effects. |
| sensory neurons | Neurons that transmit information from sensory receptors to the central nervous system in response to stimuli. |
| serotonin | A neurotransmitter involved in mood regulation, sleep, and emotional processing. |
| stimulants | Psychoactive drugs such as caffeine and cocaine that typically increase neural activity and arousal. |
| substance P | A neurotransmitter involved in pain perception and transmission. |
| threshold | The minimum level of depolarization needed to trigger an action potential in a neuron. |
| tolerance | A state in which repeated use of a psychoactive drug requires increasing doses to achieve the same effect. |
| withdrawal symptoms | Negative physical and psychological effects that occur when a person stops using a psychoactive drug to which they are addicted. |
| Term | Definition |
|---|---|
| amygdala | A brain structure within the limbic system that processes emotions, particularly fear and emotional memory. |
| aphasia | A language disorder resulting from damage to brain areas responsible for speech production or comprehension. |
| association areas | Brain regions in the parietal lobes that process and organize sensory and cognitive information. |
| brain plasticity | The ability of the brain to rewire itself, modify existing connections, or create new connections throughout development to compensate for damage or support learning. |
| brain stem | The region of the brain that controls basic life functions such as breathing and heart rate. |
| brain's reward center | The brain region that processes reward and reinforcement, influencing learning, cognition, and emotional responses. |
| Broca's area | A region in the left hemisphere responsible for speech production. |
| cerebellum | A brain structure that controls coordination of muscle movement, balance, and procedural learning. |
| cerebral cortex | The outer layer of the brain divided into two hemispheres, containing the limbic system and lobes that process sensory information and control higher-order functions. |
| contralateral hemispheric organization | The brain's organization in which each hemisphere processes sensory information from the opposite side of the body. |
| corpus callosum | A bundle of nerve fibers connecting the left and right hemispheres of the brain, allowing communication between them. |
| EEG | Electroencephalography; a brain imaging technique that measures electrical activity of the brain. |
| fMRI | Functional magnetic resonance imaging; a brain imaging technique that measures blood flow to identify active brain regions. |
| frontal lobes | Brain lobes located just behind the forehead that control linguistic processing, higher-order thinking, and executive functioning, including the motor cortex. |
| hippocampus | A brain structure within the limbic system that is essential for forming and consolidating memories. |
| hypothalamus | A brain structure within the limbic system that regulates hormones, temperature, hunger, and other homeostatic functions. |
| lesioning | A surgical procedure that damages or removes a specific brain area to study its function. |
| limbic system | A group of brain structures including the thalamus, hypothalamus, pituitary gland, hippocampus, and amygdala that regulate emotion, memory, and motivation. |
| medulla | A structure within the brain stem that regulates vital functions including breathing and heart rate. |
| motor cortex | A region located at the rear of the frontal lobes that controls most types of skeletal movement. |
| occipital lobes | Brain lobes located at the rear of the cerebral cortex that process visual information. |
| parietal lobes | Brain lobes located near the back crown of the cerebral cortex that contain association areas for processing and organizing information and the somatosensory cortex for touch sensitivity. |
| pituitary gland | An endocrine gland within the limbic system that releases hormones controlling growth, metabolism, and other bodily functions. |
| prefrontal cortex | A region of the frontal lobes responsible for executive functioning, decision-making, and higher-order thinking. |
| reticular activating system | A network of neurons in the brain that controls voluntary movement, eye movement, and influences learning, cognition, and emotion. |
| somatosensory cortex | A region in the parietal lobes that processes touch sensitivity and tactile information. |
| split brain research | Research conducted on patients with severed corpus callosums that reveals specialization of the left and right brain hemispheres. |
| temporal lobes | Brain lobes located on the sides of the cerebral cortex that process auditory and linguistic information. |
| thalamus | A brain structure that processes most sensory information before it reaches the cerebral cortex; the olfactory system bypasses this structure. |
| Wernicke's area | A region in the left hemisphere responsible for speech comprehension. |
| Term | Definition |
|---|---|
| activation-synthesis theory | A theory explaining dreams as the brain's attempt to synthesize and make sense of random neural activity during REM sleep. |
| circadian rhythm | A biological cycle that repeats approximately every 24 hours, regulating sleep-wake patterns and other physiological processes. |
| consciousness | The varying levels of awareness of thoughts, feelings, behavior, and events in an individual's internal and external worlds. |
| consolidation theory | A theory suggesting that sleep serves to organize and consolidate memories from daily experiences into long-term storage. |
| EEG patterns | Electrical brain wave recordings used to identify and distinguish the different stages of sleep. |
| hypnagogic sensations | Sensory experiences that occur as an individual enters Stage 1 sleep, marking the transition from wakefulness to sleep. |
| insomnia | A sleep disorder characterized by persistent difficulty falling or staying asleep. |
| jet lag | A disruption of the circadian rhythm caused by rapid travel across multiple time zones. |
| memory consolidation | The process by which encoded information is stabilized and integrated into long-term memory. |
| narcolepsy | A sleep disorder characterized by sudden, uncontrollable episodes of sleep during wakefulness. |
| NREM sleep | Non-rapid eye movement sleep occurring in Stages 1 through 3, characterized by specific EEG patterns and decreasing duration throughout the sleep cycle. |
| paradoxical sleep | A characteristic of REM sleep in which the brain produces waking-like electrical patterns while the body is at its most relaxed. |
| REM rebound | An increase in REM sleep that occurs after a period of REM sleep deprivation. |
| REM sleep | Rapid eye movement sleep characterized by brain waves similar to wakefulness, muscle relaxation, and where dreaming typically occurs. |
| REM sleep behavior disorder | A sleep disorder in which individuals act out their dreams during REM sleep due to loss of normal muscle paralysis. |
| restoration theory | A theory suggesting that sleep restores depleted physical and mental resources used throughout the day. |
| shift work | A disruption of the circadian rhythm caused by working at times that conflict with the body's natural sleep-wake cycle. |
| sleep apnea | A sleep disorder characterized by repeated interruptions in breathing during sleep. |
| sleep/wake cycle | The alternating pattern of sleep and wakefulness that occurs throughout a 24-hour period, affecting behavior and mental processes. |
| somnambulism | A sleep disorder characterized by complex motor behaviors and movement during sleep, commonly known as sleepwalking. |
| Term | Definition |
|---|---|
| absolute threshold | The minimum level of stimulation that can be detected at least 50% of the time. |
| accommodation | The process by which the lens focuses visual stimuli onto the retina to create a clear image. |
| afterimages | Visual images that persist after the original stimulus is removed, resulting from the activation of certain ganglion cells while others remain inactive. |
| auditory sensory system | The biological structures and processes involved in hearing, including the ear and neural pathways that detect and process sound. |
| balance | The ability to maintain equilibrium and stability of the body, controlled by the vestibular sense. |
| blind spot | The area of the retina where the optic nerve exits the eye, creating a gap in the visual field that the brain fills in to perceive a complete image. |
| blindsight | A disorder resulting from damage to visual brain areas in which individuals can respond to visual stimuli without consciously perceiving them. |
| chemical sensory systems | Sensory systems that detect chemical stimuli, including olfaction (smell) and gustation (taste). |
| cold receptors | Sensory receptors in the skin that respond to decreases in temperature and signal the sensation of cold. |
| color vision deficiency | A condition involving damage or irregularities to cones or ganglion cells that impairs color perception, including dichromatism or monochromatism. |
| conduction deafness | A type of hearing loss caused by damage to the structures that conduct sound waves through the outer and middle ear. |
| cones | Photoreceptor cells located in the fovea of the eye that process color and detail, including blue, green, and red cones that detect different wavelengths. |
| dichromatism | A type of color vision deficiency in which one type of cone or ganglion cell pair is damaged or absent, resulting in reduced color perception. |
| farsightedness | A refractive error that occurs when the accommodation process is altered, causing difficulty seeing nearby objects clearly. |
| fovea | The central region of the retina where cones are concentrated to process color and detail. |
| frequency theory | A theory of pitch perception proposing that the rate at which neurons fire corresponds to the frequency of the sound wave. |
| ganglion cells | Retinal cells involved in the opponent-process theory of color vision that are activated in opposing pairs to produce color perception. |
| gate control theory | A theory explaining how pain perception is modulated by the nervous system, suggesting that pain signals can be blocked or amplified at various points in the nervous system. |
| gustation | The sense of taste, which detects chemical compounds through taste receptors on the tongue. |
| just-noticeable difference | The smallest change in a stimulus that can be detected by an observer. |
| kinesthesis | The sense of one's own body movement and position in space, allowing coordinated movement without visual monitoring of body parts. |
| light and dark adaptation | The process by which rods adjust their sensitivity to changes in lighting conditions. |
| loudness | The perceptual intensity of sound determined by the amplitude of air molecule vibrations. |
| medium tasters | Individuals with an average number of taste receptors on their tongue, resulting in typical taste sensitivity. |
| monochromatism | A type of color vision deficiency in which only one type of cone functions or all cones are absent, resulting in the inability to perceive color. |
| nearsightedness | A refractive error that occurs when the accommodation process is altered, causing difficulty seeing distant objects clearly. |
| nontasters | Individuals with fewer taste receptors on their tongue, making them less sensitive to tastes. |
| occipital lobes | Brain lobes located at the rear of the cerebral cortex that process visual information. |
| oleogustus | A basic taste quality associated with the perception of fatty or oily substances. |
| olfactory stimuli | Chemical signals detected by the olfactory system that produce the sense of smell. |
| olfactory system | The sensory system responsible for detecting and processing smells through chemical receptors in the nose. |
| opponent-process theory | A theory of color vision explaining that color perception results from ganglion cells that are activated in opposing pairs (red/green, blue/yellow, black/white). |
| pain sensory system | The biological structures and neural pathways involved in detecting, transmitting, and processing pain signals from the body to the brain. |
| phantom limb sensation | The experience of sensation or pain in a limb that has been lost or amputated, resulting from continued neural activity in the brain's sensory cortex. |
| pheromones | Chemical substances produced by animals that communicate information to other members of the same species through the olfactory system. |
| pitch | The perceptual quality of sound determined by the frequency or wavelength of air molecule vibrations. |
| place theory | A theory of pitch perception proposing that different frequencies of sound stimulate different locations along the basilar membrane of the cochlea. |
| prosopagnosia | A disorder resulting from damage to visual brain areas, characterized by the inability to recognize faces despite intact general vision. |
| retina | The photosensitive surface at the back of the eye that captures visual information and transduces it to the brain for processing. |
| rods | Photoreceptor cells located in the periphery of the eye that detect shapes and movement but not color, and are mainly activated in low-light environments. |
| semicircular canals | Structures in the inner ear that detect rotational movements and changes in head position to maintain balance. |
| sensation | The process of detecting information from the environment that meets a certain threshold and converting stimuli into neurochemical messages for processing in the brain. |
| sensorineural deafness | A type of hearing loss caused by damage to the inner ear or the neural pathways that transmit sound information to the brain. |
| sensory adaptation | The diminished sensitivity to a stimulus that remains constant over time. |
| sensory interaction | The process by which different sensory systems work together to influence perception. |
| sound localization | The ability to identify the location or direction of a sound source in the environment. |
| supertasters | Individuals with a higher number of taste receptors on their tongue, making them more sensitive to tastes. |
| synesthesia | An experience of sensation in which stimulation of one sensory system is experienced through another sensory system. |
| taste receptors | Sensory cells on the tongue that detect and respond to different taste qualities. |
| thalamus | A brain structure that processes most sensory information before it reaches the cerebral cortex; the olfactory system bypasses this structure. |
| touch sensory system | The sensory system that processes tactile stimuli through receptors in the skin and neural pathways in the brain. |
| transduction | The process of converting physical stimuli into neurochemical messages that the brain can process. |
| trichromatic theory | A theory of color vision explaining that color perception results from three types of cones that detect different wavelengths of light. |
| umami | A basic taste quality characterized by a savory flavor, often associated with glutamate compounds. |
| vestibular sense | The sensory system that detects balance and spatial orientation, primarily through the semicircular canals in the inner ear. |
| volley theory | A theory of pitch perception proposing that groups of neurons fire in volleys to encode the frequency of sound waves. |
| warm receptors | Sensory receptors in the skin that respond to increases in temperature and signal the sensation of warmth. |
| Weber's law | A principle stating that the degree to which stimuli need to be different for the difference to be detected is proportional to the intensity of the original stimulus. |