Course 2.4 Perception 1
Problem 9: Balance
Literature: Wolfe, Coren
Vestibular organs (vestibular labyrinth/vestibular system)
= set of 5 organs (3 semicircular canals; 2 otolith organs)
- Location: inner ear; next to cochlea
- Sense motion of the head; orientation of gravity; tilt; self-motion
→ spatial orientation
- Functions:
o Clear image when in motion
o Maintain balance
- Ancient (found early in evolution), relatively unchanged
- Operates automatic/reflexive/attentional background (unconsciously)
- Damages/ malfunction may lead to:
Dizziness Spatial disorientation Blurred vision
Vertigo Imbalance Illusory self-motion
Modalities + Qualities of spatial orientation
3 sensory modalities
1. Angular motion = rotational motion e.g. shaking head in “no” motion
2. Linear motion = straight forward motion, e.g. car/train
3. Tilt = sloping position e.g. tower of Pisa
- Differ in the energy they transduce
= converting energy from one to another
1. Angular acceleration = velocity of change in angle
2. Linear acceleration (“translation”) = rate of change in velocity
3. Gravity
Sensing angular motion, linear motion and tilt
- 2 types of vestibular sense organs
1. Semicircular canals
o Sense angular acceleration
o Contribution to angular motion
2. Otolith organs
o Sense linear acceleration and gravity
o Contribution to head tilt and sense of linear motion
Basic qualities of spatial orientation
- Each of orientation modalities has 2 qualities
1. Amplitude = The size/amount of head movement
o Linear motion: high amplitude (fast; e.g. train) or low amplitude (slow; e.g. snail)
o Rotation: high amplitude (fast; e.g. shaking head quickly) or low amplitude
(slow)
o Tilt amplitude: high (lying down) or low (nodding head)
2. Direction
o Coordinate system: x-axis: points forward; y-axis: out of left ear; z-axis: out of top of the head
3 angular motions: 3 linear motions: 2 tilt directions:
1. Roll angular (barrel roll motion) 1. Along x-axis (stepping forth/back) 1. Pitch tilt
2. Pitch angular (nodding “yes”) 2. Along y-axis (sliding left/right) 2. Roll tilt
3. Yaw angular (shaking head “no”) 3. Along z-axis (jumping up/down)
Problem 9: Balance
Literature: Wolfe, Coren
Vestibular organs (vestibular labyrinth/vestibular system)
= set of 5 organs (3 semicircular canals; 2 otolith organs)
- Location: inner ear; next to cochlea
- Sense motion of the head; orientation of gravity; tilt; self-motion
→ spatial orientation
- Functions:
o Clear image when in motion
o Maintain balance
- Ancient (found early in evolution), relatively unchanged
- Operates automatic/reflexive/attentional background (unconsciously)
- Damages/ malfunction may lead to:
Dizziness Spatial disorientation Blurred vision
Vertigo Imbalance Illusory self-motion
Modalities + Qualities of spatial orientation
3 sensory modalities
1. Angular motion = rotational motion e.g. shaking head in “no” motion
2. Linear motion = straight forward motion, e.g. car/train
3. Tilt = sloping position e.g. tower of Pisa
- Differ in the energy they transduce
= converting energy from one to another
1. Angular acceleration = velocity of change in angle
2. Linear acceleration (“translation”) = rate of change in velocity
3. Gravity
Sensing angular motion, linear motion and tilt
- 2 types of vestibular sense organs
1. Semicircular canals
o Sense angular acceleration
o Contribution to angular motion
2. Otolith organs
o Sense linear acceleration and gravity
o Contribution to head tilt and sense of linear motion
Basic qualities of spatial orientation
- Each of orientation modalities has 2 qualities
1. Amplitude = The size/amount of head movement
o Linear motion: high amplitude (fast; e.g. train) or low amplitude (slow; e.g. snail)
o Rotation: high amplitude (fast; e.g. shaking head quickly) or low amplitude
(slow)
o Tilt amplitude: high (lying down) or low (nodding head)
2. Direction
o Coordinate system: x-axis: points forward; y-axis: out of left ear; z-axis: out of top of the head
3 angular motions: 3 linear motions: 2 tilt directions:
1. Roll angular (barrel roll motion) 1. Along x-axis (stepping forth/back) 1. Pitch tilt
2. Pitch angular (nodding “yes”) 2. Along y-axis (sliding left/right) 2. Roll tilt
3. Yaw angular (shaking head “no”) 3. Along z-axis (jumping up/down)
