Psy 405 Vestibular and Exotic Senses

8/18/2019 Psy 405 Vestibular and Exotic Senses

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Psy 405

The Vestibular System


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Vestibular system:

1. Perception of balance, orientationand motion

2. very primitive sensory system

3. Differs from other senses because

sensations not consciously perceived


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For all animals…

Stimulus for orientation: gravitysensory mechanism for detecting gravity:

Statocyst:Fluid filled sack lined with hairs

Statolith:Particles heavier than the fluid

http://www.youtube.com/watch?v=fUIokQ36rbA

http://www.youtube.com/watch?v=O9XtK6R1QAk&feature=related

http://www.youtube.com/watch?v=fUIokQ36rbAhttp://www.youtube.com/watch?v=O9XtK6R1QAk&feature=relatedhttp://www.youtube.com/watch?v=O9XtK6R1QAk&feature=relatedhttp://www.youtube.com/watch?v=fUIokQ36rbA


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statocyst


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Mammalian vestibular system:

Part of inner ear


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3 main organs:

Saccule

UtricleSemicircular Canals


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Utricle and Saccule: linear acceleration

Utricle: horizontal motion

Saccule: vertical motion


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Semicircular Canals: circular movements


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3 canals oriented along

3 dimensions of space


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Vestibular system responds

only to acceleration


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vision and vestibular interactions

Effects of vestibular signals on vision:

Eye reflexes to compensate for head motion

http://www.youtube.com/watch?v=j_R0LcPnZ_w

http://www.youtube.com/watch?v=U3KHgkZHuzc

http://www.youtube.com/watch?v=GiASZpZzT88

http://www.youtube.com/watch?v=j_R0LcPnZ_whttp://www.youtube.com/watch?v=U3KHgkZHuzchttp://www.youtube.com/watch?v=GiASZpZzT88http://www.youtube.com/watch?v=GiASZpZzT88http://www.youtube.com/watch?v=U3KHgkZHuzchttp://www.youtube.com/watch?v=j_R0LcPnZ_w


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Patient JC’s perception after complete loss of

his vestibular system

“By bracing my head between the bars of the bed I could minimize

the pulse beat that made the letters of the page jump and blur”

“When walking in a corridor I had the peculiar sensation that I was inside

a flexible tube, fixed at the end nearest me but swaying free at the far end”


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Effects of vestibular signals on vision:

Vestibular adaptation induces visual

Motion aftereffects


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Effects of vision on vestibular signals:

self vection:

If visual field moves you feel like you

are moving


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self vection:

If visual field moves you feel like you

are moving

e.g. IMAX theater


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visual frames of reference


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Sense of balance

e.g. try balancing on one foot


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Usually visual and vestibular signals agree


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Disagreements can lead to motion sickness


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Motion sickness most common for

Passive movement involving acceleration

Static visual fields(e.g. reading in car or sitting in ship cabin)


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Theory:

Mismatched signals typical of poisoning

Vomiting is therefore an adaptive response


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Psy 405

Still More Exotic Sensory Systems

What flowers might look like to bees?


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What flowers might look like to bees?

Visible UV


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Mantis Shrimp: The King of Color!

8 pigments for color + 2 for polarization!


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The 5 senses in plants

Vision: plants orient to the direction of the sunCan detect different wavelengths to respond to shade

Can set their circadian rhythms by light

Hearing: some roots may emit sound pulses

Touch: insect eating plants respond to very specific patterns

of movement

Smell: fruits and leaves emit odors that are detected tosynchronize ripening

Taste: roots may communicate with each other to signal

drought or disease


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Bat echolocation

2 types of bats:

Megachiroptera:Fruit eating, no echolocation

Microchiroptera:Insect eating , echolocating


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Bat sonar, though clearly a form of perception,

is not similar in its operation to any sense that

we possess, and there is no reason to suppose that it issubjectively like anything we can experience or imagine

What is it like to be a bat?

Thomas Nagel


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Echolocation not confirmed until 1940’s!

prior theory:

“felt” the air with their wings

(Maxim, Scientific Am 1912)

Solved only after invention of

high-freq sound recorders

Bat calls


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Bat calls

1.High frequency(20-40k fundamental)

2.Extremely loud(dB level of rock band or jet landing!)

3.Both constant and varying frequencycomponents

4.Changes at different phases of hunting


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human range:

20-20,000 Hz


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Dolphin and whale calls

http://killerwhale.org/fieldnotes/pics/sounds/N4.wav

Changes in call features from search, approach, to final attack


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Why such high frequencies?

Small objects (Bugs!) reflect highfrequencies better than low


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Why change the call?

As prey is approachedneed to sample more rapidly and

over wider frequency range

(feeding buzz)

Cues in the echo:

http://www.werc.usgs.gov/OLDsitedata/bats/feedingbuzz.htmlhttp://www.werc.usgs.gov/OLDsitedata/bats/feedingbuzz.html


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Cues in the echo:

1.distance:

time delay between call and returning echo

2. direction:

which ear echo is louder in

3. identity:

Frequency spectrum of the echo

4. Relative motion:

Doppler shift


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Are these cues good?

Yes!

Bats can catch ~5-10 insects / minute!

Bugs battle back!!!


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Bugs battle back!!!

Defenses:

1. AvoidanceRandom flight with moderate sound

Drop to ground with intense sound

2. Advertising

Some moths emit high frequencies

3. Stealth?

Why aren’t bats confused by other bats?


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Why aren t bats confused by other bats?


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Middle ear reflex blocks soundtransmission except at critical time

Bats can recognize their own “voices”

S


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Sonar

Common to most marine mammals

Sonar characteristics


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Sonar characteristics

Very high frequency (peak ~100 kHz)

Very intense depending onbackground noise

(e.g. “snapping” shrimp)

Very accurate

Dolphins can detect 3 in ball 120 m away!

(equal to visual stimulus falling on 4 cones)Whale sounds

http://whalesounds.com/home/index.html

http://asa.aip.org/sound.htmlhttp://whalesounds.com/home/index.htmlhttp://whalesounds.com/home/index.htmlhttp://asa.aip.org/sound.html


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Sonar problem: impedance matching

How transfer sound from air to water?

Solution: resonator (the melon)


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Other systems for detecting


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Other systems for detecting

self-generated stimuli:

electroreception


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Among mammals only monotremes


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Among mammals only monotremes

are known to have electroreception


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Bird Navigation

Visual cues:Solar

Requires circadian clock to interpret

Can bias direction by shifting clock

Bird Navigation


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Bird Navigation

Visual cues:

Celestial

Stars rotate around fixed point (north star)

Pigeons and ducks can use pattern of

rotation as a cue


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Non-visual cues:

Magnetic field:

Birds in cage without visual cues will

tend to hop toward south in fall

and north in spring

If block field hop in random directions

M i fi ld


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Magnetic field

2 cues direction and inclination


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2 cues – direction and inclination

Birds may use inclination


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Birds may use inclination

Why?

The direction keeps changing!

The magnetic field has reversed 24 times

in last 5 million years!

Many other species are sensitive


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Many other species are sensitive

to magnetic fields

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Psy 405 Vestibular and Exotic Senses