1. Lecture 3: Sensory systems involved in Motor Control

2. Why do we need senses? n Provide information for reflexive movement at the spinal cord level. n Voluntary movement: Initiate, adjust and terminate the output of movement.

3. Sensory systems n Visual n Audio/vestibular n Proprioception - Muscle spindle - Muscle spindle - GTO - GTO - Joint receptors - Joint receptors - Cutaneous (touch) - Cutaneous (touch)

4. Vision

5. The eye...

8. The eye n Retina n Photoreceptors Rods - night vision Rods - night vision Cones - daylight, color vision Cones - daylight, color vision n Fovea Sensory differentiation is a key to sensory processing (e.g. color blind).

9. Cone Rod

12. Vision... External- environment n Identify objects in space. n Determine their motion/movement Internal-our body n Where is our body in space in relation to our body and motion.

13. Vestibular system

15. Components: n Semicircular canals n Utricle and Saccule n Otolith organ Hair cells generate response due to the movement of fluid.

17. The vestibular system Sensitive to: n The position of the head in space and sudden changes in the movement of the head. n Stabilizes the eyes and maintains postural stability during stance and walking. n Abnormalities cause: dizziness, unsteadiness problems focusing our eyes and maintaining balance.

18. Proprioception n Muscle spindle n GTO n Joint n 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.

19. Muscle spindle n Located in the muscle belly of a skeletal muscle n Sensitive to stretch n Highest spindle density in the eye, hand and neck muscles (involved in eye-hand coordination).

20. Golgi Tendon Organ - GTO n Sensitive to tension n Sensitive to small amounts of tension

21. Joint receptors n Located in joint capsules n Sensitive to joint angles - provide danger signals

22. Cutaneous n Mechanoreceptors - mechanical stimuli n Thermoreceptors - temp. n Nociceptors - potential damage to the skin. Cutaneous info. gives rise to reflex movements e.g. bottom of the foot.

24. Characteristics of the sensory information n Where is the stimulus? n What is the intensity? n What is the duration? Transmission to other systems