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Psychology 205

Perception

Day 08

13 Feb 03

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Haptics, Posture, & Movement

Neuro-muscular Apparatus

detection thresholds, Golgi tendon andmuscle spindle organ, & an illusion

HapticsVestibular Apparatus

responses to: linear accelerationangular acceleration

Balancegravito-inertial force

endolymphs & density 2heat, alcohol, and H2O

Contributions of & to Visiongaze-stability

motion sickness

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right hemisphere,

reversed from Day 07

front

back

Sylvian

fissure

fissure of Rolando

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sensory humunculus

weighted by corticalarea

motor humunculus

weighted by corticalarea

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look for noncorrespondences

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Neuro-muscular apparatusknowing where youre muscles are

---> Kinesthesis

1. Golgi tendon organson tendons of extrafusal muscles

long muscles within muscle bundle

isotonic exercise -->change in muscle length

2. muscle spindle organsin intrafusal muscles

short muscles within muscle bundle

isometric exercise -->change in resistance

a kinesthetic illusion

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Extrafusal = slow twitch -->distance runners

Intrafusal = fast twitch --> sprinters, body

builders

sensory organs about the state of muscles (feedback),not the nerves signaling the muscles to twitch; afferent

(conducting inward), not efferent(conducting outward)

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Activity in: Intrafusal Extrafusal

muscle Golgi

spindle tendonorgan organ

1. muscles at rest somes.n.a.

2. muscles lengthened lots some

3. muscles shortened s.n.a some

(isotonic)

4. muscles at rest length lots s.n.a.but flexed(isometric)

s.n.a. = spontaneous neural activity

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Activity in: Intrafusal Extrafusal

muscle Golgi

spindle tendon

organ organ

2. muscles lengthened yes yes

4. muscles at rest length yes no

but flexed(isometric)3. muscles shortened no yes

(isotonic)

curl in weightlifting

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Analog in Cutaneous senses

Activity in: Temperature receptorswarm cold

Hot yes yes

Warm yes noCold no yes

coding of a continuous dimension, often with two

populations of receptors

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illusions

illusory felt positions

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Arm position

with vibratedtendon

perceivedarm position

vibration stimulatesboth muscle tendon

and spindle organs

--> lengthened muscle

perceived lengthened muscle

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Haptics = active touch (Day 07) + kinesthesis

touch sensations from hand

(object schema)

andmuscle sensations from hand & arm

(body schema)

investigation of muscle sensations alone

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perception ofshape by wielding

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d lit

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= 60 trials

chance = 20%

Performance =37%

Information?:

Different inertial properties

in different directions

cross modalitymatching

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Vestibular apparatus6 degrees of freedom in movement

(the Galilean group)linear acceleration

side-to-side: utricle macula,

front-back: saccule otolithsup-down: both

angular accelerationrotations: semicircular canals

ampulla, crista, cupola

vestibulo-ocular reflex (VOR)doll reflex

visual direction, vestibulo-muscular adaptation, &

baseball players

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6 degreesof freedom

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3 semicircularcanals

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0

th

derivative spatial position

1st derivative velocitychange in position

2nd derivativeaccelerationchange in velocitychange in the change of position

3rd

derivative jerkchange in accelerationchange in the change of velocitychange in the change in the change

of position

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inside utricleand saccule

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consider onesemicircular canalin horizontal plane

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dizziness after spins

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Balance

against forces

of acceleration

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Balance

even when not

necessary

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endolymph ~water, slightly salty

What is the cause of instability when blood alcohol is elevated?

1. part of the global effect of alcohol

2. direct effect of the specific gravity of alcohol (lighter than water)

heavy water - deuterium oxide 2

H2O

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Gaze-stability systems

Vestibulo-Ocular Response (VOR) -- y axis rotation (yaw)

Doll Reflex -- x axis rotation (pitch)

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ocular reflexes and adaptation

visual direction,vestibulo-muscular adaptation,& baseball players

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the role of vision in balance and vection

perception of self-motionGunnar Johansson

David Lee

sustained (slowly adapting) cells - cortex

transient (rapidly adapting) cells - cortex & central core

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H i P & M

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Haptics, Posture, & Movement

Neuro-muscular Apparatus

detection thresholds, Golgi tendon andmuscle spindle organ, & an illusion

HapticsVestibular Apparatus

responses to: linear accelerationangular acceleration

Balancegravito-inertial force

endolymphs & density 2heat, alcohol, and H2O

Contributions of & to Visiongaze-stability

ti i k