Quiz4 Flashcards
Evidence for Speech is Special
-It is processed and handled by the brain in a unique way
-Speech is processed in its own special regions of the brain
-Broca’s area and Wernicke’s area (production and comprehension). Speech is impaired with lesions here
Evidence Against Speech is Special
-It is processed like any other learned pattern
-Musicians (but not non-musicians) also process music in these regions (more than speech being processed here)
What Makes Speech Redundant
There is a lot of information with speech and you don’t need all that information
In what situations is redundancy important?
Speech in noisy environment. You can understand speech even when missing some information
How categorical perception is related to instructions
-If the listener is tasked with identifying two different sounds, they will task them into binary categories despite a gradual change.
-If tasked with identifying if a sound is a good prototype, people are able to rate which speech token is a good example of a phoneme. Generally not categorical here.
Where Else is Redundancy seen?
Crickets do this to distinguish between mates and predators
Neural Network
-When a group of neurons cause another neuron to fire, the connection between them strengthens
-aka Hebbian learning
-Categorical perception naturally comes out of this, so it shows speech is not special
Perceptual Magnet
-It is more difficult to distinguish speech tokens that are near the syllable prototype (acoustically similar)
-Bird prototype example: Robin is a bird, ostrich is also a bird
-Different from categorical perception because categorical perception has distinct categories that separate the phonemes
Ototoxicity Definition
Medicines that can damage hair cells
Ototoxicity damage
Damages…
-Inner hair cells
-Outer hair cells
via buildup of reactive oxygen species causing cell death
Ototoxic Medication Examples
-Gentamicin (anitbiotic) (damages IHC)
-Cisplatin (cancer) (damages OHC, spiral ganglion, and stria)
-Vicoden (pain)
-NSAIDs (pain) (less BM movement)
Noise Exposure Effects
-Noise exposure drives metabolic activity
-Causes buildup of reactive oxygen species causing cell death of stria vascularis (key for endolymph) and OHC
-Reduces blood flow to cochlea which deprives cells of needed oxygen
-Earbuds drive louder volumes (closer to TM)
-Lower concentration gradient of K+ in endolymph, less drive for K+ to flow in
Connexin 26 Mutation
-Critical for forming gap junctions that maintain K+ concentration in endolypmh
-Endolymph and perilymph start mixing
DFNB12 Mutation
-Progressive loss of tiplinks in animals
-Results in congenital deafness in humans
Auditory Neuropathy
-Reflects problems with the transmission for signals from the cochlea to the brain
-Related to a decrease in the synchrony of firing in the auditory nerve (lose temporal information)
-Normal OAEs, abnormal ABR
-Normal pure-tone thresholds, but struggle in noisy environments
-Difficulty with gap detection
-Can treat with cochlear implants (increasing synchrony with lots more neurons firing)
Meniere’s disease
-Caused by excess fluid in the inner ear
-Vertigo
-Hearing loss
-Aural fullness
-Tinnitus
-Treatments still being researched
Acoustic Neuroma
-Tumor on CN VIII
-Slow growing and benign
-Reason for a patient with asymmetric loss to get an MRI
-If grown too large, needs to be removed, cutting CN VIII causing hearing loss
Wernicke’s Aphasia
-Comprehension problem
-Fluent but generally meaningless speech
Tumors
Benign but can push against structures as they grow along auditory pathway
Neurofibromatosis Type 2 (NF2)
-Genetic disorder that results in a proliferation of tumors in the nervous system (tumors on CN VIII too)
-Hearing loss
-Tinnitus
-Balance problems
-Numbness/Weakness
-Headache and seizure
-Cataracts
NF2 Treatment
More about management
-Annual MRI
-Annual vision and hearing checks
Presbycusis
-Age-related hearing loss
-Environmental component of loudness and duration of sounds exposed to over a lifetime
-Genetic component too
-Periphery and central damages
Presbycusis symptoms
-Lack of clarity of speech
-Inaudibility of sounds
-Difficulty in noisy environments
-Hyperacusis
-Tinnitus
-Loss of temporal activity
-Decreased contralateral suppression of OAE
Multiple Sclerosis
-Demyelinating disease
-Subpopulation of patients have hearing loss, difficulty in noisy environments, and lateralization difficulty
Stroke
Can occasionally affect auditory functions
-Cochlear nucleus = Ipsilateral or bilateral hearing loss
-Lateral lemniscus = difficulty using interaural time and level differences
-Inferior colliculus = difficulty using interaural time and level differences
-Auditory Cortex =Deafness if damage is bilateral
Five types of taste
-Sweet
-Salty
-Bitter
-Sour
-Umami
Taste Receptors
- Ion channels (Salty, sour, bitter)
- Binding and G-proteins; metabotropic (bitter, sweet, umami)
Taste vs. Smell receptors
Taste=Only 5
Smell=Hundreds
Olfactory Receptors
All G-protein coupled receptors (metabotropic) vs. taste which uses G-proteins and ion channels
Orbitofrontal Cortex
Where taste and smell information converge
Somatosensation is Responsible for…
-Pain
-Temperature
-Touch
-Proprioception
Types of Somatosensation Receptors
-Mechanoreception
-Thermoreception
-Nociception
Mechanoreception
-Receptor that opens in response to mechanical force
Responsible for
-Touch
-Pressure
-Vibration
-Proprioception
-Kinesthesia
Proprioception
Awareness of limb position in space
Kinesthesia
Awareness of limb movement
Why are proprioception and kinesthesia important?
Cerebellar pathways; correcting of ongoing motion; you get proprioceptive or kinesthetic feedback that something went wrong
Thermo-reception
-Sensation of cold and heat (temperature)
-Mediated by temperature-gated channels
-These channels can also be gated by certain chemicals
-If receptor is sensitive to warm temperatures, you get more action potentials as you increase temperature from a cool temperature
-For ones sensitive to cold temperatures, you get less and less action potentials as temperature rises
Nociception
-Sensation of pain
-Some nociceptors are temperature gated, some are sensitive to force
-Respond like normal mechano and thermo-receptors, but the range they respond to is different
-Nociceptors don’t give action potentials until you get into fairly extreme temperatures
Referred Pain
-Pain is not always perceived from stimulation location
-typical of visceral pain
-pain is localized based on a shared pathway with nearby non-visceral nociceptors
Receptor Types
Different types of receptors carry different information
Encapsulated endings
Discriminative Touch
Free nerve endings
pain and temperature
Extended tip endings
touch, temperature, and pressure
Three neuron pathways
-First-order neurons
-Second-order neurons
-Third-order neurons
First order neurons
-Collect sensory information from the periphery
-Specialized purpose, need to respond to what they come in contact with
Second-order neurons
-Found in spinal cord or brainstem
-Their projections cross the midline (allows us to diagnose based on damage)
third-order neurons
-Found in thalamus
-Their projections go to the primary sensory cortex
Dorsal Column-medial Lemniscal system
Responsible for
-Discriminative touch
-Postural position
-Midline crossing happens at the medulla (brainstem)
Two point touch
Mechanorecptors have receptive fields of varying size
-Fingers
-Palm
-Forearm
-Lips
Receptive field
Neuron’s view of the world. How much of the world that a particular neuron sees
Topographical organization
Similar layout between motor and sensory cortex, but size of representation is different
Lateral spinothalamic tract
Responsible for sensation of
-Pain
-Tempearture
-Crosses midline immediately at level of the spinal cord
Anterior spinothalamic tract
Responsible for the sensation of
-Diffuse/non-localized touch (backup system for discriminative touch)
-Crosses midline at point of spinal cord where things enter
-Usually unaware of this system
Trigeminal nerve system
Responsible for sensation from the face, intraoral cavity, head, external ear, ear canal, and tympanic membrane
-Cross over happens in the brainstem
Unconscious proprioception
-Unconscious proprioception is a back up for the discriminative system
-Vital for acquisition of skilled motor activities
-Never aware of the system
-Two-neuron pathways (not making last jump to cortex)
-Ipsilateral and contralateral projections
-Damage to one side = not many symptoms
