Sensation and Perception Exam 3 - Chapters 9-12

Sounds (Pressure Change)

Created when objects vibrate. This creates pressure changes in the medium.

Longitudinal Wave

a wave in which the particles of the medium vibrate parallel to the direction of wave motion.

Acoustic Reflex

A reflex of the stapedius muscle in the middle ear in response to loud/high intensity sounds to protect the inner ear from potential damage. Follows onset of loud sounds by 200 ms.

Complex Sound

A spectrum that displays how much energy is present in each of the frequencies in the sound.

Fourier Analysis

Break complex waveforms into its pure tone components.

Pitch

The psychological aspect of sound related mainly to the perceived frequency.

Frequency

Is associated with pitch. Low frequency = low pitch. High frequency = high pitch.

Hertz

Measure of frequency. 1 Hz = 1 cycle per second.

Decibel

Unit of measurement for the physical intensity of a sound. Defined by the differences in two sounds as the ratio between the two sound pressures.

Loundness

The psychological aspect of sound related to perceived intensity (amplitude).

Amplitude

The magnitude of displacement of a sound pressure wave. The height of a sound wave.

Human Frequency Range

20 Hz to 20,000 Hz

Human Decibel Range

0 dB to 120 dB

Fundamental Frequency

The lowest frequency component of a complex periodic sound.

Harmonic Spectrum

The spectrum of a complex sound in which energy is at integer multiples of the fundamental frequency.

Timbre

The psychological sensation in which a listener can judge that two sounds with the same loudness and pitch are dissimilar.

Outer Ear

Sounds from environment are collected by the pinnae. Sound waves are funneled by the pinnae into the ear canal. The length and shape of the ear canal enhances certain sound frequencies.

Middle Ear

Contains ossicles that transmit sound vibrations from tympanic membrane to inner ear. Uses tensor tympani and stapedius to modulate sound intensity and protect inner ear.

Inner Ear

Fine changes in sound pressure are transduced into neural signals.

Tonotopic Organization

An arrangement in which neurons that respond to different frequencies are organized anatomically in order of frequency.

Psychoacoustics

The branch of psychophysics that studies the psychological correlations of the physical dimensions of acoustics in order to understand how the auditory system operates.

White Noise

Noise consisting of all audible frequencies in equal amounts.

Tympanic Membrane

The eardrum. A thin sheet of skin at the end of the outer ear canal. Vibrates in response to sound.

Ceruminous Glands

Modified sweat glands, located in external ear canal. Produces earwax.

Malleus

One of the three ossicles. Receives vibrations from the tympanic membrane and is attached to the incus.

Incus

The middle ossicle.

Stapes

One of the three ossicles. Connected to the incus on one end and the oval window of the cochlea at the other end.

Two Primary Functions of Ossicles

-Transmit sound signals from the tympanic membrane to the inner ear

-Modulate sound intensity before arriving in the inner ear

Organ of Corti

A structure on the basilar membrane of the cochlea that is composed of hair cells and dendrites of auditory nerve fibers. Movements of the cochlear partition are translated into neural signals by structures in the organ of corti.

Hair Cells

Cells that support the stereocilia, which transduce mechanical movement in the cochlea into neural activity sent to the brain stem. Some hair cells also receive input from the brain.

Stereocilia

Hairlike extensions on the tips of hair cells in the cochlea that, when flexed, initiate the release of neurotransmitters.

Cochlea

Spiral structure of the inner ear containing the organ of corti. The cochlea is filled with watery fluids in three parallel canals.

Vestibular Canal

One of the three canals of the cochlea. Extends from oval window at the base of the cochlea to helicotrema at the apex. Canal closest to ossilcles and through which pressures waves move first.

Tympanic Canal

One of the three canals of the cochlea. Extends from helicotrema at the apex to the round window at the base of the cochlea.

Middle Canal

One of the three canals of the cochlea. Contains the cochlear partition.

Primary Auditory Cortex

The first area within the temporal lobes of the brain responsible for processing acoustic organization.

Medial Geniculate Nucleus

The part of the thalamus that relays auditory signals to the temporal cortex and receives input from the auditory complex.

Inferior Colliculus

A midbrain nucleus in the auditory pathway.

Superior Olive

An early brain stem region in the auditory pathways where inputs from both ears converge.

Cochlear Nucleus

The first brain stem nucleus at which afferent auditory nerve fibers synapse.

Auditory Nerve Fiber

A collection of neurons that convey information from the hair cells in the cochlea to the brain.

Conductive Hearing Loss

Hearing loss caused by problems with the ossicles of the middle ear.

Sensorineural Hearing Loss

Most common hearing loss caused by defects in the cochlea or auditory nerve.

Metabolic- Hair cells are injured by chemicals or infection

Sensory- Damage to hair cells by excessive loud noise

Sound Localization

The process by which the location of sound is determined.

Interaural Time Differences (ITD)

The difference in time between sound arriving in one ear versus the other.

Azimuth

The angle of a sound source on the horizontal plane relative to a point in the center of the head between the ears.

Medial Superior Olive (MSO)

A relay station in the brainstem where inputs from both ears contribute to the detection of Interaural Time Differences (ITDs).

Interaural Level Difference (ILD)

The difference in level (intensity) between a sound arriving at one ear versus the other.

Lateral Superior Olive (LSO)

A relay station in the brain stem where inputs from both ears contribute to the detection of Interaural Level Differences (ILDs).

Coen of Confusion

A region of positions in space where all sounds produce the same ITDs and ILDs.

Cues for Auditory Distance Perception

-Relative intensity of sound

-Inverse-square law (as distance from a source increased, intensity decreases faster

-Higher frequencies decrease in energy more than lower frequencies as sound waves travel from a source to one ear

-Relative amounts of direct versus reverberant energy

Absolute Pitch

A rare ability whereby some people are able to very accurately name or produce notes without comparison to other notes.

Vocal Tract

The airway above the larynx used for the production of speech.

Vocal tract

Area above the larynx. flexibility is important in speech production.

Respiration

Inhalation and exhalation of air. Diaphragm pushes air out of lungs, through the trachea, up to larynx.

Phonation

The process through which vocal folds are made to vibrate when air is pushed out of the lungs.

Articulation

the act or manner of producing a speech sound using the vocal tract.

The McGurk Effect

an error in perception that occurs when we misperceive sounds because the audio and visual parts of the speech are mismatched.

Vestibular Organs

The set of five organs, three semicircular canals and two otolith organs, located in the inner ear that sense head motion and head orientation with respect to gravity.

Otolith Organs

The mechanical structures in the vestibular system that sense both linear acceleration and gravity.

Utricle

Otolith organ that has about 30,000 hair cells. Detects horizontal linear acceleration and gravity.

Saccule

Otolith organ that has about 16,000 hair cells. Detects vertical linear acceleration and gravity.

Otoconia

Tiny calcium carbonate stones in the ear that provide inertial mass for the otolith organs, enabling them to sense gravity and linear acceleration.

Semicircular Canals

The three toroidal tubes in the vestibular system that sense angular acceleration, a change in angular velocity.

Anterior, Posterior, Horizontal Semicircular Canals

Filled with a fluid called perilymph. Formed by a membrane filled with fluid called endolymph.

Ampulla

An expansion of each semicircular-canal duct that includes that canal's cupula, crista, and hair cells where transduction occurs.

Vestibulo-ocular Reflex (VOR)

Counter-rotating the eyes to counteract head movements and maintain fixation on a target.

Balance System

The sensory systems, neural processes, and muscles that contribute to postural control.

Active Sensing

Sensing that includes self-generated probing of the environment.

Sensory Reafference

Changes in afference caused by self-generated activity.

Sensory Exafference

Changes in afference caused by external stimuli.

Afferent Signals

Flow from our senses to our brain.

Efferent Commands

Flow from our brain to our muscles.

Graviception

The physiological structures and processes that sense the relative orientation of gravity with respect to the organism.

Spatial Orientation

A sense consisting of three interacting sensory modalities, perception of linear motion, angular motion, and tilt.

Linear Motion

Sensed when accelerating or decelerating in a car.

Angular Motion

Sensed when rotating head from side to side.

Tilt

Sensed as orientation as respect to gravity.

Mechanoreceptor

A sensory receptor that responds to mechanical stimulation (pressure, vibration, or movement).

Push-Pull Symmetry

Hair cells in opposite ears respond in a complementary fashion to each other. When hair cells in the left ear depolarize, those in the analogous structure in the right ear hyperpolarize.

Spatial Cognition

Understanding and organizing 3D space.

Sensory Integration

The process of combining different sensory signals.

Self-Vection

An illusory sense of self motion produced when you are not, in fact, moving.

Proprioception

The ability to tell where one's body is in space.