PSYC 132 FINAL

Frequency (Sound)

Measured in Hertz (Hz); determines pitch. Higher frequency = higher pitch.

Amplitude (Sound)

Measured in decibels (dB); determines loudness. Higher amplitude = louder sound.

Pure Tone

A sound consisting of a single frequency.

Complex Tone

A sound made of multiple frequencies combined.

Timbre

The quality of a sound that allows us to distinguish different instruments playing the same note.

Pinna

The outer ear that collects sound and helps localize sound.

External Auditory Canal

Conducts sound from the pinna to the eardrum.

Tympanic Membrane

The eardrum; vibrates in response to sound waves.

Ossicles

The three bones of the middle ear: malleus, incus, and stapes.

Function of Ossicles

Transmit sound, amplify sound, and protect the inner ear from sustained loud noises.

Eustachian Tube

Equalizes air pressure on both sides of the eardrum.

Cochlea

Snail-shaped structure of the inner ear that contains hair cells for hearing.

Hair Cells

Sensory receptors that convert vibrations into neural signals.

Transduction (Audition)

The conversion of sound vibrations into neural impulses.

Auditory Transduction Pathway

Sound → Pinna → Ear canal → Eardrum → Ossicles → Oval window → Cochlea → Hair cells → Auditory nerve.

Place Coding Theory

Different locations along the basilar membrane respond to different frequencies.

Base of Basilar Membrane

Responds to high-frequency sounds.

Apex of Basilar Membrane

Responds to low-frequency sounds.

Auditory Nerve (CN VIII)

Carries auditory information from the cochlea to the brain.

Auditory Pathway

Cochlea → Auditory nerve → Cochlear nucleus → Superior olive → Inferior colliculus → Medial geniculate nucleus (thalamus) → Primary auditory cortex.

Superior Olive

Receives input from both ears and helps localize sound.

Medial Geniculate Nucleus

The auditory relay nucleus of the thalamus.

Primary Auditory Cortex (A1)

First cortical area that processes sound.

Tonotopic Organization

Neurons are organized according to the frequencies they respond to.

What Auditory Pathway

Identifies sounds, speech, and music.

Where Auditory Pathway

Determines the location of sounds.

Binaural Cues

Require both ears; used for left-right localization.

Monaural Cues

Require only one ear; used for elevation and distance judgments.

Interaural Time Difference (ITD)

Difference in arrival time of sound between ears; best for low-frequency sounds.

Interaural Level Difference (ILD)

Difference in sound intensity between ears caused by the head blocking sound; best for high-frequency sounds.

Cone of Confusion

Different locations produce identical ITDs and ILDs, making sound location ambiguous.

Spectral Shape Cue

Sound localization cue produced by the pinna; helps determine elevation.

Temporal Segregation

Sounds occurring at the same time are grouped together.

Spatial Segregation

Sounds from the same location are grouped together.

Spectral Segregation

Sounds with overlapping frequencies are grouped together.

Auditory Scene Analysis

The process of separating multiple sounds into distinct sources.

Auditory Continuity

The brain perceives a sound as continuous even when briefly interrupted by another sound.

Cutaneous Senses

Senses detected through the skin: touch, temperature, and pain.

Epidermis

Outermost layer of skin that protects against pathogens and water loss.

Dermis

Inner layer containing most sensory receptors.

Subcutaneous Layer

Fat and connective tissue beneath the dermis.

Warm Fibers

Detect temperatures above approximately 36°C; located deeper in the skin.

Cold Fibers

Detect temperatures below approximately 30°C; located closer to the skin surface and are myelinated.

Thermoreceptors

Receptors that detect changes in skin temperature.

Temperature Adaptation

Skin becomes less responsive to prolonged hot or cold stimulation.

Nociceptors

Receptors that detect tissue damage and pain.

A-delta Fibers

Myelinated pain fibers that transmit fast, sharp pain.

C Fibers

Unmyelinated pain fibers that transmit slow, dull, aching pain.

Bottom-Up Pain

Pain determined primarily by nociceptor input.

Top-Down Pain

Pain influenced by mood, attention, expectations, and emotions.

Phantom Limb Pain

Pain perceived in a limb that has been amputated.

Mechanoreceptors

Touch receptors found in the skin.

Merkel Receptors

Slow-adapting receptors that detect pressure, texture, and fine detail.

Meissner Corpuscles

Fast-adapting receptors that detect changes in light touch.

Ruffini Endings

Slow-adapting receptors that detect skin stretch.

Pacinian Corpuscles

Fast-adapting receptors that detect vibration and deep pressure.

Fast-Adapting Receptors

Respond mainly at the beginning and end of stimulation (Meissner and Pacinian).

Slow-Adapting Receptors

Respond continuously while stimulation is present (Merkel and Ruffini).

Dorsal Column-Medial Lemniscal Pathway

Carries touch information; crosses the body in the medulla.

Spinothalamic Pathway

Carries pain and temperature information; crosses the body in the spinal cord.

Primary Somatosensory Cortex

Identifies where touch occurs on the body.

Higher Somatosensory Areas

Help identify what object is touching the body.

Somatosensory Homunculus

A map of the body on the cortex where more sensitive body parts have larger cortical representation.

Proprioception

Perception of the position of body parts.

Kinesthesis

Perception of limb movement.

Vestibular Sense

Sense of balance, movement, and head position.

Muscle Spindles

Detect muscle stretch.

Joint Receptors

Detect joint angle.

Golgi Tendon Organs

Detect muscle force and tendon tension.

Semicircular Canals

Detect rotational movement of the head.

Otolith Organs

Detect gravity and linear acceleration.

Utricle

Detects horizontal acceleration.

Saccule

Detects vertical acceleration.

VR Sickness

Thought to result from conflicting visual, vestibular, and proprioceptive information.

Chemosenses

The chemical senses: smell (olfaction) and taste (gustation).

Olfaction

The sense of smell.

Gustation

The sense of taste.

Odorants

Chemicals dissolved in the air that stimulate smell receptors.

Tastants

Chemicals dissolved in saliva that stimulate taste receptors.

Olfactory Epithelium

Sensory tissue inside the nasal cavity containing olfactory receptor neurons.

Olfactory Receptor Neurons

Neurons that detect odorants; regenerate about every month.

Orthonasal Olfaction

Smelling through the nostrils.

Retronasal Olfaction

Smelling through the mouth during eating.

Olfactory Bulb

Processes smell information before sending it to the brain.

Unique Feature of Olfaction

It is the only sense that does not first relay through the thalamus.

Piriform Cortex

Primary olfactory cortex.

Anterior Piriform Cortex

Organizes odors according to chemical structure.

Posterior Piriform Cortex

Organizes odors according to perceptual similarity.

Amygdala (Olfaction)

Processes emotional aspects of smell.

Hippocampus (Olfaction)

Involved in odor memories.

Anosmia

Loss of the sense of smell.

Hyperosmia

Enhanced sensitivity to smells.

Odor Perceptual Learning

Improved odor identification through training and experience.

Five Basic Tastes

Sweet, salty, sour, bitter, and umami.

Sweet

Signals energy-rich foods.

Salty

Signals the presence of ions.

Sour

Can signal spoiled food or acidity.

Bitter

Can signal toxins.

Umami

Signals amino acids and protein.

Taste Map Myth

The tongue does not have separate regions for each taste; all tastes can be detected across the tongue.