Sensation & Perception – Core Vocabulary

Fifty key vocabulary flashcards covering fundamental terms and structures in sensation and perception, including sensory organs, neural mechanisms, and major theories discussed in the lecture notes.

Sensation

Initial detection and encoding of environmental stimuli by sense organs and the brain.

Perception

Organization and meaningful interpretation of sensory information by the brain.

Transduction

Conversion of a physical stimulus into electrical signals within receptor cells.

Neural Coding

Processing of sensory inputs to represent stimulus intensity and quality in neural activity.

Action Potential

Brief electrical impulse (+40 mV peak) that travels along an axon once threshold (≈ –55 mV) is reached.

Kinesthesis

Sense that monitors the position and movement of body parts.

Olfactory Bulb

Brain structure that receives input from smell receptors and begins olfactory processing.

Olfactory Receptor Cell

Sensory neuron in the nasal cavity whose cilia bind odor molecules.

Hippocampus

Limbic‐system structure critical for forming long-term memories.

Thalamus

Major relay station for early sensory processing, alertness, and attention.

Hypothalamus

Brain region regulating drives, emotions, and many bodily functions.

Amygdala

Limbic structure important for fear detection, emotional memory, and stress regulation.

Taste Bud

Cluster of gustatory receptor cells located in papillae on the tongue and other oral areas.

Salty Taste

Basic taste quality triggered by sodium (Na⁺) ions.

Sour Taste

Basic taste quality produced by acids (H⁺ ions), often signaling spoilage.

Sweet Taste

Basic taste quality elicited by sugars, generally indicating nutritive value.

Bitter Taste

Basic taste quality often associated with alkaloids and potential toxins.

Menthol

Mint component that activates receptors also stimulated by cold temperatures.

Capsaicin

Chili-pepper compound that activates receptors also stimulated by heat.

Pinna

Visible outer-ear structure that funnels sound waves into the auditory canal.

Eardrum (Tympanic Membrane)

Membrane that vibrates in response to sound waves, transferring energy to middle-ear bones.

Malleus, Incus, Stapes

Three small middle-ear bones (hammer, anvil, stirrup) that amplify vibrations to the inner ear.

Oval Window

Membrane at the entrance to the cochlea where stapes transmits vibrations.

Cochlea

Fluid-filled inner-ear structure that converts mechanical vibrations into neural signals.

Basilar Membrane

Structure inside the cochlea whose varying stiffness allows place coding of sound frequency.

Frequency (Pitch)

Number of sound wave cycles per second; higher frequency equals higher perceived pitch.

Amplitude (Loudness)

Height of sound waves; greater amplitude equals louder sound.

Duplex Theory of Vision

Idea that rods mediate low-light vision and cones mediate color vision in bright light.

Rod

Retinal photoreceptor with high sensitivity, low acuity, functioning in dim light and periphery.

Cone

Retinal photoreceptor requiring bright light, providing color vision and high acuity at the fovea.

Adaptation (Sensory)

Reduction in receptor response during prolonged or repeated stimulation.

Opponent-Process Theory

Color vision theory proposing antagonistic red/green and blue/yellow receptor pairs.

Contrast (Lateral Interaction)

Change in a receptor’s response depending on activity in neighboring regions (spatial interaction).

Lateral Inhibition

Process where activated neurons inhibit their neighbors, sharpening sensory contrast.

Receptive Field

Region of sensory surface that, when stimulated, alters the firing rate of a neuron.

Simple Cortical Cell

V1 neuron that responds best to a bar of light at a specific orientation and location.

Complex Cortical Cell

V1/V2 neuron that responds to edges or bars moving in a preferred direction regardless of exact position.

Hypercomplex Cell

Visual cortical neuron tuned to very specific lengths, corners, or gaps in stimuli.

Magnocellular Pathway (M-Cells)

Visual pathway with large receptive fields, transient responses, coding motion and gross form.

Parvocellular Pathway (P-Cells)

Visual pathway with small receptive fields, sustained responses, coding color and fine detail.

Dorsal Stream (“Where” Pathway)

Visual pathway projecting to parietal lobe, specialized for spatial location and motion.

Ventral Stream (“What” Pathway)

Visual pathway projecting to temporal lobe, specialized for object recognition and color.

Myelin Sheath

Fatty insulation around many axons that speeds action-potential conduction via nodes of Ranvier.

Node of Ranvier

Gap in the myelin sheath where ion exchange occurs, enabling saltatory conduction.

Photopigment

Light-sensitive chemical inside rods or cones that absorbs photons to initiate transduction.

Fovea

Central retinal region with highest cone density and greatest visual acuity.

Optic Nerve

Bundle of ganglion-cell axons transmitting visual signals from retina to brain.

Lateral Geniculate Nucleus (LGN)

Thalamic relay station with magnocellular and parvocellular layers for visual input.

Solitary Nucleus (NTS)

Brainstem structure receiving taste information from cranial nerves VII, IX, and X.

Sensory Interaction Principle

Concept that current sensory experience depends on prior stimulation and surrounding context.