Psychology: Neuroscience, Behaviour, Sensation, and Perception

Comprehensive vocabulary flashcards covering key terms and concepts across neuroscience, the nervous system, sensation, and perception from psychology lecture notes.

Neurons

Cells in the nervous system that communicate with one another to perform information-processing tasks.

Glial Cells

Support cells found in the nervous system that provide physical and nutritional support, digest dead neurons, and form the insulating myelin sheath.

Cell Body (Soma)

The largest component of a neuron that coordinates information-processing tasks, maintains metabolism, and houses the cell nucleus containing DNA.

Dendrites

Tree branch-like structures extending from the neuron that receive input from other neurons and convey it toward the cell body.

Axon

The elongated extension of a neuron that conducts information away from the cell body to other neurons, muscles, or glands.

Myelin Sheath

An insulating layer of fatty tissue formed by glial cells that encloses sections of an axon to accelerate electrical transmission.

Synapse

The microscopic intercellular gap between the axon terminal of a presynaptic neuron and the dendrites or soma of a postsynaptic neuron where signals are transmitted.

Sensory Neurons

Neurons that receive sensory input from the external environment and transmit this information to the brain via the spinal cord.

Motor Neurons

Neurons that convey motor instructions from the spinal cord to muscle fibres to initiate muscular contractions and movement.

Interneurons

Neurons that connect sensory neurons, motor neurons, or other interneurons, making up the vast majority of the central nervous system.

Purkinje Cells

A specialized type of interneuron that carries neural information from the cerebrum to the remainder of the brain and spinal cord.

Bipolar Cells

A type of sensory neuron located in the retina of the eye characterized by having a single axon and a single dendrite.

Mirror Neurons

Neurons located in the frontal and parietal lobes that activate both when an organism performs a goal-directed motor action and when observing another individual perform the same action.

Resting Potential

The difference in electrical charge across a neuron's cell membrane when at rest, typically measuring approximately $-70\,\text{mV}$ due to higher internal concentrations of potassium ions ($\text{K}^+$) and external sodium ions ($\text{Na}^+$).

Action Potential

An all-or-none electrical impulse conducted along the length of an axon reaching approximately $+40\,\text{mV}$ triggered when membrane depolarization attains threshold.

Refractory Period

The temporal phase immediately following an action potential during which a neuron cannot initiate a new action potential because ion channels are resetting, ensuring forward conduction.

Saltatory Conduction

The rapid transmission of an action potential along a myelinated axon, regenerated at the nodes of Ranvier so that the impulse appears to jump from node to node.

Nodes of Ranvier

Small unmyelinated gaps along an axon situated between segments of the myelin sheath where action potentials are regenerated.

Terminal Buttons

Knoblike structures located at the terminal ends of an axon containing synaptic vesicles loaded with neurotransmitters.

Vesicles

Small membranous sacs within presynaptic terminal buttons that store neurotransmitter molecules prior to exocytosis.

Neurotransmitters

Chemical messengers synthesized by neurons that traverse the synaptic gap to transmit signals to receptor sites on postsynaptic membranes.

Receptors

Specialized protein structures situated on the postsynaptic membrane that bind specific neurotransmitters in a lock-and-key fashion to initiate or inhibit a neural signal.

Reuptake

The termination mechanism whereby released neurotransmitters are retrieved from the synaptic cleft back into the presynaptic terminal buttons or adjacent glial cells.

Autoreceptors

Presynaptic receptor sites that detect the concentration of released neurotransmitters and signal the presynaptic neuron to halt further release.

Acetylcholine (ACh)

A neurotransmitter regulating voluntary motor control, attention, learning, and memory; degradation of ACh-producing neurons is linked to Alzheimer's disease.

Glutamate

The primary excitatory neurotransmitter of the brain that increases postsynaptic firing probability; excessive accumulation can induce seizures.

GABA (Gamma-Aminobutyric Acid)

The primary inhibitory neurotransmitter in the brain that suppresses neuronal firing; insufficient levels are associated with seizures.

Dopamine (DA)

A neurotransmitter modulating motor behavior, motivation, pleasure, and emotional arousal; depleted levels produce Parkinson's disease, whereas elevated activity is implicated in schizophrenia.

Norepinephrine (NE)

A neurotransmitter that regulates mood, vigilance, autonomic arousal, and physiological alertness; diminished levels are linked to depression.

Serotonin (5-HT)

A neurotransmitter governing sleep, wakefulness, appetite, and aggressive behavior; reduced concentrations are implicated in mood disorders such as depression.

Endorphins

Endogenously produced neuropeptides that inhibit pain transmission and elevate mood states, contributing to phenomena such as the runner's high.

Agonists

Exogenous or endogenous chemical agents that bind to receptors and mimic or amplify the action of a specific neurotransmitter.

Antagonists

Substances that impede, decrease, or obstruct the normal physiological action of a neurotransmitter by blocking its receptor sites.

Central Nervous System (CNS)

The major division of the nervous system consisting exclusively of the brain and the spinal cord.

Peripheral Nervous System (PNS)

The division of the nervous system comprising all neural structures outside the central nervous system, linking the CNS to organs, sensory receptors, and muscles.

Somatic Nervous System

A subdivision of the peripheral nervous system consisting of nerves that convey sensory inputs to the CNS and transmit voluntary motor commands to skeletal muscles.

Autonomic Nervous System

A subdivision of the peripheral nervous system that directs involuntary and automatic functions controlling blood vessels, internal viscera, and endocrine glands.

Sympathetic Nervous System

The division of the autonomic nervous system that mobilizes metabolic resources and accelerates bodily functions to prepare the organism for fight-or-flight scenarios.

Parasympathetic Nervous System

The branch of the autonomic nervous system that slows physiological activation and restores vegetative resting states to preserve energy.

Reflex Arc

A neural communication pathway mediating an involuntary reflex action, directing sensory impulses through the spinal cord directly to motor neurons without prerequisite cerebral processing.

Medulla

A structure of the hindbrain extending from the spinal cord into the skull that regulates heart rate, blood circulation, and respiration.

Reticular Formation

A small network of neurons originating in the medulla and projecting upward through the midbrain that modulates arousal, sleep, and wakefulness.

Cerebellum

A large posterior hindbrain structure that refines, coordinates, and smooths fine motor movements without initiating primary contractions.

Pons

A hindbrain structure situated above the medulla that relays motor and sensory information between the cerebellum and the rest of the brain.

Tectum

A dorsal midbrain structure that coordinates an organism's physical orientation toward environmental visual, auditory, and tactile stimuli.

Tegmentum

A midbrain structure situated beneath the tectum involved in motor control, movement, and physiological arousal.

Thalamus

A subcortical forebrain relay hub that filters, processes, and directs incoming sensory information to designated areas of the cerebral cortex for all modalities except olfaction.

Hypothalamus

A subcortical structure located below the thalamus that governs fundamental homeostatic drives including body temperature, hunger, thirst, and sexual behaviour.

Hippocampus

A limbic system subcortical structure critical for the acquisition, formation, and consolidation of new conscious memories into permanent long-term storage.

Amygdala

A subcortical forebrain structure located at the tip of each horn of the hippocampus that processes intense emotions, particularly fear, and encodes emotional memories.

Basal Ganglia

A collection of subcortical forebrain nuclei, including the striatum, that coordinate voluntary motor actions and process reward signals.

Corpus Callosum

The largest cerebral commissure, consisting of a dense band of nerve fibres connecting corresponding regions of the left and right cerebral hemispheres to facilitate interhemispheric communication.

Occipital Lobe

The posterior cortical lobe dedicated to receiving and processing visual sensory input, containing the primary visual cortex (area V1).

Parietal Lobe

The cortical lobe situated anterior to the occipital lobe containing the somatosensory cortex, responsible for processing tactile sensations and body position.

Temporal Lobe

The inferior lateral cortical lobe containing the primary auditory cortex (area A1), responsible for hearing, language comprehension, and visual association processing.

Frontal Lobe

The anterior cortical lobe housing regions responsible for voluntary motor commands, abstract thought, planning, judgement, and executive functioning.

Brain Plasticity

The capacity of neural circuits to reorganize, alter synaptic connectivity, and reassign cortical functions in response to learning, environmental experience, or bodily damage.

Epigenetics

The study of environmental influences that alter whether and how genes are expressed (through DNA methylation and histone modification) without modifying underlying DNA base sequences.

Heritability

A statistical parameter expressed as a proportion ranging from $0.00\,\text{to}\,1.00$ that indexes the extent to which phenotypic variance among individuals in a population is attributable to genetic variance.

Sensation

The simple physiological detection and registration of environmental physical stimuli by peripheral sense organs.

Perception

The central cognitive process of organizing, identifying, and interpreting sensory information in the brain to produce a meaningful mental representation.

Transduction

The biological process wherein specialized sensory receptors convert environmental physical or chemical energies into electrical and chemical neural signals.

Psychophysics

An experimental discipline founded by Gustav Fechner that systematically measures the relationship between physical stimulus characteristics and an observer's subjective perceptual experience.

Absolute Threshold

The minimal physical intensity of a stimulus required for an observer to successfully detect its presence $50\%$ of the time.

Just Noticeable Difference (JND)

The smallest physical change or difference in intensity between two sensory stimuli that an observer can reliably detect.

Weber's Law

The psychophysical principle establishing that the just noticeable difference is a constant proportion of the original stimulus magnitude rather than a constant absolute value.

Signal Detection Theory

A perceptual framework stating that the detection of a target stimulus amid noise depends simultaneously upon an observer's sensory sensitivity and their internal decision criterion.

Sensory Adaptation

The progressive reduction in sensory responsiveness that occurs when receptors are exposed to continuous, unchanging environmental stimulation.

Synesthesia

A perceptual condition occurring in approximately $1\,\text{in}\,100$ individuals where stimulation of one sensory pathway spontaneously evokes an experience within an unrelated sensory modality.

Accommodation

The optical mechanism whereby the eye's ciliary muscles change the shape of the crystalline lens, flattening for distant objects and rounding for nearby objects to maintain focus on the retina.

Rods

Photoreceptor cells distributed in the peripheral retina that function under scotopic (dim) lighting conditions and register visual input in shades of grey.

Cones

Photoreceptor cells concentrated in the fovea that operate under photopic (daylight) conditions to provide fine spatial detail and chromatic colour vision.

Fovea

The central focal region of the retina consisting entirely of densely packed cones and lacking rods, responsible for maximum visual acuity.

Ventral Stream

The visual pathway projecting from the primary visual cortex (occipital lobe) forward into the temporal lobe ('what' pathway) that identifies an object's form and identity.

Dorsal Stream

The visual pathway projecting from the primary visual cortex up into the parietal lobe ('where/how' pathway) that determines an object's spatial location and guides motor interactions.

Binding Problem

The theoretical question of how the human brain integrates disparate visual features (such as motion, orientation, and colour) processed across distributed brain areas into a single coherent percept.

Perceptual Constancy

The perceptual tendency to recognize the intrinsic properties of an object (such as size or shape) as remaining invariant despite dramatic variations in the sensory image cast upon the retina.

Cochlea

A fluid-filled, coiled structure of the inner ear housing the basilar membrane where fluid waves induce mechanical motion to stimulate auditory transduction.

Basilar Membrane

An undulating inner ear tissue within the cochlea that flexes in response to acoustic vibrations, activating embedded auditory receptor cells.

Hair Cells

Specialized mechanoreceptive auditory transducer cells embedded in the basilar membrane that convert physical mechanical movement into neural impulses via the auditory nerve.

Haptic Perception

The active sensory exploration of surfaces and objects through manual physical contact and grasping.

A-Delta Fibres

Myelinated, fast-conducting nociceptive nerve fibres that transmit the initial, acute, sharp pain experienced immediately after tissue injury.

C-Fibres

Unmyelinated, slow-conducting nociceptive nerve fibres that transmit dull, persistent, throbbing pain sensations following physical trauma.

Gate-Control Theory of Pain

The physiological model proposing that spinal interneurons can inhibit or facilitate the transmission of pain signals to the brain through peripheral cutaneous feedback and descending cortical influences.

Referred Pain

A sensory anomaly in which nociceptive signals originating in visceral internal organs are perceived as occurring on the somatic surface of the body due to convergent spinal pathways.

Proprioception

The kinesthetic sense that monitors bodily position, limb orientation, and movement via specialized sensory receptors situated in skeletal muscles, tendons, and joints.

Vestibular System

The sensory apparatus located adjacent to the cochlea in the inner ear comprising three semicircular canals whose fluid and hair cells monitor balance, head rotation, and acceleration.

Olfactory Receptor Neurons (ORNs)

Receptor neurons residing in the olfactory epithelium whose mucosal receptor sites bind airborne odorant molecules to initiate smell transduction.

Papillae

Visible protuberances distributed across the dorsal surface of the tongue that house taste buds, the biological organs of gustatory transduction.