Lecture 19 Flashcards
How do sound waves from the environment ultimately get translated into neural signals in the brain?
Sound waves are captured by the outer ear, which leads to vibrations in the middle ear and transduction by hair cells in the inner ear. These signals are then transmitted to the brain.
What are sound waves, and what causes them?
Sound waves are caused by areas of high and low pressure propagating outward from a sound source.
Name the three parts of the ear and briefly describe their functions.
The three parts are the outer ear (captures sound), middle ear (transmits vibrations), and inner ear (houses auditory receptors).
What role does the pinna play in the auditory system?
The pinna captures sound and focuses it into the auditory canal.
How does the middle ear amplify sound signals?
Sound waves cause the eardrum to vibrate, which, in turn, vibrates the middle ear bones (ossicles).
What are the structures of the inner ear, and what role does the cochlea play?
The inner ear includes the cochlea, which contains hair cells that serve as auditory receptors. It converts mechanical signals into electrical signals.
What is the primary function of spiral ganglion cells in the cochlea?
Spiral ganglion cells are sensitive to specific frequencies and transmit auditory information to the brain.
Define tinnitus and briefly explain its possible causes.
Tinnitus is the perception of noises in the absence of an external sound. It can be caused by cochlear or auditory nerve issues.
How does auditory information travel from the inner ear to the central nervous system (CNS)?
Auditory information travels via the vestibulocochlear nerve to the brain stem.
Where does the auditory information first synapse in the brain after leaving the cochlea?
Auditory information first synapses in the cochlear nuclei in the brain stem.
What is the primary function of primary auditory cortex (A1)?
A1 processes sound and maintains the tonotopic organization of frequencies.
How does the brain localize the source of a sound based on interaural time differences?
Interaural time differences are differences in the arrival time of a sound at each ear, helping localize sound sources.
What cues are used for determining the elevation of sound sources?
Elevation cues are based on the reflections of sound from the bumps and ridges of the outer ear.
Describe the general pathway of auditory information from the external ear to the primary auditory cortex.
Information travels through the external ear, middle ear, inner ear, brain stem, thalamus, and finally to the primary auditory cortex.
Why is bilateral projection of auditory information to both brain hemispheres important?
Bilateral projection allows for redundancy and better preservation of auditory function if one hemisphere is damaged.
