Sensory Systems at ETHZ - ETH Zurich | Flashcards & Summaries

Lernmaterialien für Sensory Systems an der ETHZ - ETH Zurich

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TESTE DEIN WISSEN

What is the function of the auditory descending pathway?

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descending projections of similar magnitude

unique feature of auditory system: projections (indirect) up to peripheral epithelium 

-> speculation: top-down modulation of sensory input

expectation of sound -> modulation of sensory input channels

select certain frequencies (amplify and reduce certain frequencies)

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TESTE DEIN WISSEN

What are the physical properties of sound?

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TESTE DEIN WISSEN
  • Sound: pressure (longitudinal) wave propagating in medium
  • There are two different kind of waves: longitudinal and mechanical 
  • properties used as information to hear:
    • Displacement (particles moved away)
    • air pressure variations = sound pressure
  • speed of sound through air: 343m/s
  • speed of sound through water: 1484m/s
  • wavelength lambda = speed c/ frequency f
  • particle velocity v= distance / time
  • every stimuli can be seen as a sum of sinusoidal waves 
    • natural stimuli are rarely sinusoidal
  • sound pressure level (SPL) is a logarithmic measure relative to a relevance value
    • 0 dB SPL = 20µPa
    • Human hearing threshold for 1kHz tone (10pm nuclear movement)
    • dynamic range: 0-120 dB SPL
  • audible spectrum: 0.02-20kHz
  • humans hear sound pressure


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TESTE DEIN WISSEN

What are hair cells and what do they do?

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TESTE DEIN WISSEN
  • have stereo cilia: only actin filament (-> not real cilia)
  • are responsible for sensory transaction (transform movement of fluid into electrical signal) -> and formation of receptor potential (on top of cilia -> tip-links are responsible)
  • There different types, which have each different functions
  • They are very sensitiv structures
    • Ototoxicity can come form antibiotics, chemotherapeutic agents, aspirin or viagra
Lösung ausblenden
TESTE DEIN WISSEN

Compare IHC with OHC

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TESTE DEIN WISSEN

Inner Hair Cells: 

  • not attached to tectorial membrane
  • have a lower threshold
  • responsible for sensory transduction
  • are more sensitive
  • innervated by auditory nerve
  • loss of IHC = loss of hearing (except for bird -> regenerate)

Outer Hair Cells:

  • attached to tectorial membrane
  • electromotility: elongate and contract
  • amplify movement of tectorial and basilar membrane
  • actively amply sound
  • innervated by auditory nerve
  • loss of OHC = hearing still intact
Lösung ausblenden
TESTE DEIN WISSEN

Why can the cochlea not be a passive organ?

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TESTE DEIN WISSEN
  • there is a sharp tunning of the auditory nerve
  • there are strong vibrations of basilar membrane at low sound intensities
  • otoacoustic emissions 
    • sounds of cochlear urging, which can be recorded by a microphone fitted into ear canal, they are caused by the motion of sensory hair cells -> energetically responds auditory stimulation
    • sign of healthy hearing
    • clinical relevance: checking of peripheral hearing -> used to screen newborns (maybe implant needed)
    • spontaneous measure of 5kHz tone continuously produced by hair cells
  • distortion feature: active amplifying systems -> other sounds can be heard
Lösung ausblenden
TESTE DEIN WISSEN

How is the information of frequency transducted?

Lösung anzeigen
TESTE DEIN WISSEN
  • activity locked to the stimulus
  • "place code" of frequencies along the cochlear tonotopy

Receptor potential -> auditory nerve innervating resonance place in basilar membrane -> actual potential generated in brainstem - nucleus cochlea's (first auditory nucleus on descending auditory pathway)


Receptor potential: important for spatial hearing

place code: important to discriminate frequencies

auditory fovea (bats): region over presented in basilar membrane -> echo-location and social communication

Lösung ausblenden
TESTE DEIN WISSEN

How is the auditory ascending pathway set up?

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TESTE DEIN WISSEN

1) cochlear nuclei

  • input from auditory nerve
  • 3 nuclei
  • monoaural projection (does not cross midline)

2) olivary complex (part of brainstem)

  • sound localization

3) inferior colliculus (part of brainstem)

  • auditory space map
  • different places correspond to auditory space in front of face
  • mammals compte auditory time different to birds

4) medial geniculate body (part of thalamus)

  • selective fro frequency combination
  • complex circuit shapes and influences sensory processing/ representation =thalamocortical loop

5) auditory cortex

  • primar auditory cortex
  • belt areas surround primary and secondary areas


-> composed of 6 synapses (more compared to visual system: 3)

computation takes place along the ascending auditory pathway


auditory cortex sits at the temporal lobe -> tonotopy is maintained from cochlea to auditory cortex

occipital = high frequencies

frontal = low frequencies 


-> damage of Wernicke's area = no understanding of speech

left brain: language and speech processing

right brain: proceed and sound processing 

Lösung ausblenden
TESTE DEIN WISSEN

What is Corticofugal modulation?

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TESTE DEIN WISSEN

When focused on visual or auditory targets the otoacoustic emissions were modulated through different attentional states

Lösung ausblenden
TESTE DEIN WISSEN

How do humans hear music?

Lösung anzeigen
TESTE DEIN WISSEN

it is a very computational phenomenom

if 5th and 3rd harmonics are shown to a human ear -> the fundamental tones will be heard, because the brain reconstructs it


The difference between instruments is where fundamental frequencies and harmonics resonate

Lösung ausblenden
TESTE DEIN WISSEN

How does a cochlear prothesis work?

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TESTE DEIN WISSEN
  • Implant has 22 electrodes (if it were smaller the electrical fields would overlap -> worse resolution)
  • The "natural" cochlea is destroyed with implantation -> covers 400-6000 Hz
  • The implant is considered for patients with profound sensorineural hearing loss
  • The auditory nerve has to be suctioning ( else it cannot be stimulated)


Audio input has to be decomposed to stimulate the right part of the auditory nerve -> filler bank -> envelope detection -> adaptation of dynamic range-> generation of stimuli 

Lösung ausblenden
TESTE DEIN WISSEN

What are the functions of the olfactory sense?

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TESTE DEIN WISSEN
  • detection and localisation of airborne molecules
    • performance and speed can be trained (dogs are still better)
    • spatial resolution is important for localization
  • detection of ingested tastands
  • detection about irritating/ noxious molecules


Lösung ausblenden
TESTE DEIN WISSEN

What can the human nose detect?

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TESTE DEIN WISSEN
  • discrimination up to a billion smells
  • detection threshold differs for each substance (ozone: 10/billion, ethanol 2'000/billion)
  • can smell the difference between enantiomers
  • dogs can smell melanoma (high accuracy)
  • anosmia: cannot smell the difference between substances
    • age
    • disease
    • damage
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  • 60330 Karteikarten
  • 1248 Studierende
  • 74 Lernmaterialien

Beispielhafte Karteikarten für deinen Sensory Systems Kurs an der ETHZ - ETH Zurich - von Kommilitonen auf StudySmarter erstellt!

Q:

What is the function of the auditory descending pathway?

A:

descending projections of similar magnitude

unique feature of auditory system: projections (indirect) up to peripheral epithelium 

-> speculation: top-down modulation of sensory input

expectation of sound -> modulation of sensory input channels

select certain frequencies (amplify and reduce certain frequencies)

Q:

What are the physical properties of sound?

A:
  • Sound: pressure (longitudinal) wave propagating in medium
  • There are two different kind of waves: longitudinal and mechanical 
  • properties used as information to hear:
    • Displacement (particles moved away)
    • air pressure variations = sound pressure
  • speed of sound through air: 343m/s
  • speed of sound through water: 1484m/s
  • wavelength lambda = speed c/ frequency f
  • particle velocity v= distance / time
  • every stimuli can be seen as a sum of sinusoidal waves 
    • natural stimuli are rarely sinusoidal
  • sound pressure level (SPL) is a logarithmic measure relative to a relevance value
    • 0 dB SPL = 20µPa
    • Human hearing threshold for 1kHz tone (10pm nuclear movement)
    • dynamic range: 0-120 dB SPL
  • audible spectrum: 0.02-20kHz
  • humans hear sound pressure


Q:

What are hair cells and what do they do?

A:
  • have stereo cilia: only actin filament (-> not real cilia)
  • are responsible for sensory transaction (transform movement of fluid into electrical signal) -> and formation of receptor potential (on top of cilia -> tip-links are responsible)
  • There different types, which have each different functions
  • They are very sensitiv structures
    • Ototoxicity can come form antibiotics, chemotherapeutic agents, aspirin or viagra
Q:

Compare IHC with OHC

A:

Inner Hair Cells: 

  • not attached to tectorial membrane
  • have a lower threshold
  • responsible for sensory transduction
  • are more sensitive
  • innervated by auditory nerve
  • loss of IHC = loss of hearing (except for bird -> regenerate)

Outer Hair Cells:

  • attached to tectorial membrane
  • electromotility: elongate and contract
  • amplify movement of tectorial and basilar membrane
  • actively amply sound
  • innervated by auditory nerve
  • loss of OHC = hearing still intact
Q:

Why can the cochlea not be a passive organ?

A:
  • there is a sharp tunning of the auditory nerve
  • there are strong vibrations of basilar membrane at low sound intensities
  • otoacoustic emissions 
    • sounds of cochlear urging, which can be recorded by a microphone fitted into ear canal, they are caused by the motion of sensory hair cells -> energetically responds auditory stimulation
    • sign of healthy hearing
    • clinical relevance: checking of peripheral hearing -> used to screen newborns (maybe implant needed)
    • spontaneous measure of 5kHz tone continuously produced by hair cells
  • distortion feature: active amplifying systems -> other sounds can be heard
Mehr Karteikarten anzeigen
Q:

How is the information of frequency transducted?

A:
  • activity locked to the stimulus
  • "place code" of frequencies along the cochlear tonotopy

Receptor potential -> auditory nerve innervating resonance place in basilar membrane -> actual potential generated in brainstem - nucleus cochlea's (first auditory nucleus on descending auditory pathway)


Receptor potential: important for spatial hearing

place code: important to discriminate frequencies

auditory fovea (bats): region over presented in basilar membrane -> echo-location and social communication

Q:

How is the auditory ascending pathway set up?

A:

1) cochlear nuclei

  • input from auditory nerve
  • 3 nuclei
  • monoaural projection (does not cross midline)

2) olivary complex (part of brainstem)

  • sound localization

3) inferior colliculus (part of brainstem)

  • auditory space map
  • different places correspond to auditory space in front of face
  • mammals compte auditory time different to birds

4) medial geniculate body (part of thalamus)

  • selective fro frequency combination
  • complex circuit shapes and influences sensory processing/ representation =thalamocortical loop

5) auditory cortex

  • primar auditory cortex
  • belt areas surround primary and secondary areas


-> composed of 6 synapses (more compared to visual system: 3)

computation takes place along the ascending auditory pathway


auditory cortex sits at the temporal lobe -> tonotopy is maintained from cochlea to auditory cortex

occipital = high frequencies

frontal = low frequencies 


-> damage of Wernicke's area = no understanding of speech

left brain: language and speech processing

right brain: proceed and sound processing 

Q:

What is Corticofugal modulation?

A:

When focused on visual or auditory targets the otoacoustic emissions were modulated through different attentional states

Q:

How do humans hear music?

A:

it is a very computational phenomenom

if 5th and 3rd harmonics are shown to a human ear -> the fundamental tones will be heard, because the brain reconstructs it


The difference between instruments is where fundamental frequencies and harmonics resonate

Q:

How does a cochlear prothesis work?

A:
  • Implant has 22 electrodes (if it were smaller the electrical fields would overlap -> worse resolution)
  • The "natural" cochlea is destroyed with implantation -> covers 400-6000 Hz
  • The implant is considered for patients with profound sensorineural hearing loss
  • The auditory nerve has to be suctioning ( else it cannot be stimulated)


Audio input has to be decomposed to stimulate the right part of the auditory nerve -> filler bank -> envelope detection -> adaptation of dynamic range-> generation of stimuli 

Q:

What are the functions of the olfactory sense?

A:
  • detection and localisation of airborne molecules
    • performance and speed can be trained (dogs are still better)
    • spatial resolution is important for localization
  • detection of ingested tastands
  • detection about irritating/ noxious molecules


Q:

What can the human nose detect?

A:
  • discrimination up to a billion smells
  • detection threshold differs for each substance (ozone: 10/billion, ethanol 2'000/billion)
  • can smell the difference between enantiomers
  • dogs can smell melanoma (high accuracy)
  • anosmia: cannot smell the difference between substances
    • age
    • disease
    • damage
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