Download Lecture 3:

Lecture 3:
Sensory systems involved in
Motor Control
Why do we need senses?
Provide information for reflexive
movement at the spinal cord level.
 Voluntary movement:
Initiate, adjust and terminate the output
of movement.

Sensory systems
Visual
 Audio/vestibular
 Proprioception

- Muscle spindle
- GTO
- Joint receptors
- Cutaneous (touch)
Vision
The eye...
The eye
Retina
 Photoreceptors
Rods - night vision
Cones - daylight, color vision
 Fovea

Sensory differentiation is a key to sensory
processing (e.g. color blind).
Cone
Rod
Vision...
Externalenvironment
Internal-our body
Identify objects in
space.
 Determine their
motion/movement


Where is our
body in space in
relation to our
body and motion.
Vestibular system
Components:
 Semicircular
canals
 Utricle and Saccule
 Otolith organ
Hair cells generate response due to
the movement of fluid.
The vestibular system
Sensitive to:
 The position of the head in space and
sudden changes in the movement of the
head.
 Stabilizes the eyes and maintains
postural stability during stance and
walking.

Abnormalities cause: dizziness, unsteadiness
problems focusing our eyes and maintaining
balance.
Proprioception
Muscle spindle
 GTO
 Joint
 Cutanous
-Provide information of location and
movement with relation of parts of the
body to other parts of the body.
-Provide information to motor control.

Muscle spindle
Located in the muscle belly of a skeletal
muscle
 Sensitive to stretch
 Highest spindle density in the eye, hand
and neck muscles (involved in eye-hand
coordination).

Golgi Tendon Organ - GTO
 Sensitive
to tension
 Sensitive to small amounts of
tension
Joint receptors
 Located
in joint capsules
 Sensitive to joint angles - provide
danger signals
Cutaneous
Mechanoreceptors - mechanical stimuli
 Thermoreceptors - temp.
 Nociceptors - potential damage to the
skin.

Cutaneous info. gives rise to reflex
movements e.g. bottom of the foot.
Characteristics of the sensory
information
 Where
is the stimulus?
 What is the intensity?
 What is the duration?
Transmission to other systems