Sensation, Perception, and Neuroscience Vocabulary Flashcards

Vocabulary flashcards generated directly from lecture transcript notes covering perception, sensory thresholds, neural mechanisms, synaptic transmission, brain structures, cognitive neuropsychology, and neuroimaging technologies.

Perception

The brain’s mental process of organizing and interpreting raw sensory data to give it meaning.

Sensation

The passive, physical process of sensory organs detecting raw environmental energy.

Senses

The physiological systems (like sight, hearing, touch) used to detect environmental stimuli.

Stimuli

Plural of stimulus; any physical energy or changes in the environment that can evoke a response.

Distal stimulus

The actual, physical object or event out in the external environment.

Proximal stimulus

The precise pattern of physical energy that directly touches and activates sensory receptors.

Sensory receptors

Specialized cells that convert physical environmental energy into electrical neural signals.

Transduction

The biological process of converting physical energy (like light) into electrical neural signals.

Neural signals

The electrical and chemical messages used by the nervous system to transmit information.

Representations

Mental structures or brain states that stand for, or symbolize, things in the real world.

Bottom-up information/processing

Analyzing raw sensory data coming from the environment to build a perception from scratch.

Top-down information/processing

Using prior knowledge, memories, and expectations to influence how sensory data is interpreted.

Psychophysics

The scientific study of the quantitative relationship between physical stimuli and psychological experience.

Neural code

The specific pattern of electrical firing that represents sensory information in the brain.

Natural selection

The evolutionary process where traits that aid survival and reproduction are passed down to future generations.

Absolute threshold

The minimum intensity of a physical stimulus needed for a person to detect it $50\%$ of the time.

Difference threshold / Just Noticeable Difference (JND)

The minimum difference required between two stimuli for a person to detect a change $50\%$ of the time.

Method of adjustment

A threshold testing method where the participant manually adjusts the stimulus intensity until they can just barely detect it.

Method of constant stimuli

A threshold testing method where a fixed set of stimuli of predetermined intensities are presented in a random order.

Staircase method

An adaptive threshold testing method where the stimulus intensity is raised or lowered based on whether the participant detected the previous one.

Psychometric function

A mathematical graph plotting the intensity of a stimulus against the percentage of times a participant detects it.

Weber’s law

A psychological principle stating that the just noticeable difference is a constant proportion of the original stimulus intensity.

Weber fraction

The specific constant ratio (proportion) that defines the difference threshold for a given sense.

Psychophysical scaling

The mathematical process of measuring how the perceived psychological magnitude changes as physical intensity changes.

Fechner’s law

A mathematical formula stating that subjective sensation grows logarithmically as physical intensity increases ($S = k \log(I)$).

Magnitude estimation

A psychophysical task where participants assign numerical values to estimate the subjective strength of a stimulus.

Stevens’s power law

A mathematical formula that models a wider range of sensory dimensions than Fechner's law, using an exponent ($S = cI^n$).

Neurons

Cells specialized for receiving, processing, and transmitting electrical and chemical signals in the nervous system.

Neuron doctrine

The fundamental concept that the nervous system is made of discrete, individual cells rather than a continuous web.

Cell body / Soma

The central part of a neuron that contains the nucleus and maintains the cell's life.

Dendrites

Branch-like extensions of a neuron that receive signals from other cells.

Axon

The long, tube-like fiber of a neuron that carries electrical impulses away from the cell body toward other neurons.

Axon terminals

Button-like structures at the end of an axon that release chemical messengers into the synapse.

Cell membrane

The semi-permeable protective outer barrier of a cell that controls what moves in and out.

Nerve

A bundled bundle of individual neuron axons travelling together in the peripheral nervous system.

Ion

An atom or molecule that carries a positive or negative electrical charge.

Ion channels

Specialized pore proteins in the cell membrane that allow specific ions to pass through.

Membrane potential

The electrical charge difference (voltage) between the inside and outside of a cell membrane.

Resting potential

The stable electrical charge of a neuron when it is not active, typically around $-70\,mV$.

Depolarization

A shift in electrical charge that makes the inside of a neuron more positive, moving it closer to firing.

Action potential

A rapid, brief electrical impulse that travels down a neuron's axon when it fires.

Refractory period

A brief recovery phase after an action potential during which a neuron cannot fire another impulse.

Firing rate

The number of action potentials a neuron produces per second.

Baseline firing rate

The low, steady rate of electrical impulses a neuron fires even when it is not being stimulated.

Single-cell recording

A neuroscience technique where a tiny electrode measures the electrical activity of one single neuron.

Synapse

The microscopic gap where two neurons meet and exchange chemical messages.

Presynaptic membrane

The surface membrane of the axon terminal that releases neurotransmitters into the synapse.

Postsynaptic membrane

The surface membrane of the receiving dendrite or cell body that contains receptor sites.

Neurotransmitters

Chemical messengers released by a neuron to transmit signals to a neighboring cell.

Synaptic vesicles

Tiny, sphere-like sacs inside axon terminals that store neurotransmitters.

Excitatory neurotransmitters

Chemicals that push the receiving neuron closer to firing an action potential.

Inhibitory neurotransmitters

Chemicals that prevent or stop the receiving neuron from firing an action potential.

Excitatory postsynaptic potential (EPSP)

A temporary, localized electrical depolarization that makes the postsynaptic neuron more likely to fire.

Inhibitory postsynaptic potential (IPSP)

A temporary, localized electrical hyperpolarization that makes the postsynaptic neuron less likely to fire.

Cerebral cortex

The highly folded outer layer of gray matter covering the brain, responsible for complex thought and perception.

Cerebral hemispheres

The symmetrical left and right halves of the cerebrum.

Corpus callosum

A large, thick band of nerve fibers connecting the left and right hemispheres so they can communicate.

Gray matter

Brain tissue composed mostly of neuron cell bodies, dendrites, and unmyelinated fibers.

White matter

Brain tissue composed mostly of myelinated axons, specialized for carrying signals fast across long distances.

Gyrus

A prominent, raised ridge or bump on the folded surface of the cerebral cortex.

Sulcus

A shallow groove or valley between the ridges on the surface of the cerebral cortex.

Frontal lobe

The front region of the cortex responsible for motor control, decision making, planning, and language.

Parietal lobe

The upper-middle region of the cortex that processes spatial awareness and bodily sensations like touch and temperature.

Temporal lobe

The lower-side region of the cortex responsible for processing auditory information, memory, and complex language.

Occipital lobe

The rear region of the cortex dedicated almost entirely to processing visual information.

Thalamus

The central sensory relay station of the brain that sorts and forwards sensory signals to the proper cortical areas.

Cognitive neuropsychology

The study of brain-damaged patients to understand the architecture of normal human cognition.

Modularity

The concept that specific cognitive functions are handled by distinct, independent structures or 'modules' in the brain.

Assumption of cognitive uniformity

The guiding idea that the basic structural organization of cognition is identical across all healthy humans.

Dissociation

A pattern of brain damage where a patient performs poorly on task A but functions normally on task B.

Double dissociation

The strongest clinical evidence showing two brain functions are independent; Patient 1 has damage to area X and can do task B but not A, while Patient 2 has damage to area Y and can do task A but not B.

Functional neuroimaging

An umbrella term for technologies that measure changes in brain activity over time while a person is awake and performing a task.

Electroencephalography (EEG)

A neuroimaging tool that records the brain's overall electrical activity via electrodes placed on the scalp, offering great timing accuracy.

Magnetoencephalography (MEG)

A neuroimaging tool that measures the tiny magnetic fields produced by the brain's active electrical currents.

Positron emission tomography (PET)

A neuroimaging tool that tracks brain metabolism by injecting a safe radioactive tracer into the bloodstream.

Functional magnetic resonance imaging (fMRI)

A neuroimaging tool that tracks active brain regions by monitoring changes in blood oxygen levels (BOLD signal).

Diffuse optical tomography (DOT)

A portable neuroimaging tool that shines harmless near-infrared light through the scalp to map brain tissue properties and oxygen levels.

Lidar

Light Detection and Ranging; a remote sensing technology that uses laser pulses to map physical distances and environments, often compared to biological perception mechanisms.