1. Sensory Components of Motor Control
Chapter 6
Sensory Components of Motor Control
Concept: Touch, proprioception and vision are important components of motor control
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2. ©2011 McGraw-Hill Higher Education.
Introduction
Sensory information is essential for all theories of motor control and learning
__________________________________
Provides feedback about the movement in progress
_______________________________________________________________________
Focus of current chapter is three types of sensory information
___________________________________
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3. Touch and Motor Control
Neural basis of touch [see Fig. 6.1]
______________________
Mechanoreceptors located in the dermis layer of skin
________________________________
___________________________________________________________________
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4. Touch and Motor Control, cont’d
Roles of Tactile Info in Motor Control
Typical research technique
Compare performance of task involving finger(s) before and after anesthetizing finger(s)
Research shows tactile sensory info influences:
___________________
____________________
__________________________________________
See an example of research for typing – A Closer Look, p. 111
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5. __________________________________________________________________
Proprioception: The sensory system’s detection and reception of movement and spatial position of limbs, trunk, and head
We will use the term synonymously with the term “kinesthesis”
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6. _________________________________
_______ receives proprioception information from sensory neural pathways that begin in specialized sensory neurons known as proprioceptors
_____________________________________________________________________________
Three primary types of proprioceptors
____________________________
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7. Neural Basis of Proprioception: Proprioceptors
1. ___________________________
In most skeletal muscles in a capsule of specialized muscle fibers and sensory neurons
_____________________________[see Fig. 6.2]
________________________________________
Mechanoreceptors that detect changes in muscle fiber length (i.e. stretch) and velocity (i.e. speed of stretch)
Function - Feedback mechanism to CNS to maintain intended limb movement position, direction, and velocity
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8. Neural Basis of Proprioception: Proprioceptors, cont’d
3. __________________
Several types located in joint capsule and ligaments
Mechanoreceptors that detect changes in
Force and rotation applied to the joint,
Joint movement angle, especially at the extreme limits of angular movement or joint positions
2. _____________________________
In skeletal muscle near insertion of tendon
________________________________(i.e. force)
Poor detectors of muscle length changes
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9. Techniques to Investigate the Role of Propioception in Motor Control
1. Deafferentation Techniques
______________________________
Afferent neutral pathways associated with movements of interest have been surgically removed or altered
Deafferentation due to sensory neuropathy
Sometimes called “_____________________”
___________________________________________________________________________________________________________________
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Techniques to Investigate the Role of Propioception in Motor Control, cont’d
2. ____________________________
______________________________________________________________
Proprioceptive feedback is distorted rather than removed
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11. Role of Proprioceptive Feedback in Motor Control
Research using deafferentation and tendon vibration techniques has shown that proprioception influences:
____________________________________
Target accuracy
Spatial and temporal accuracy for movement in progress
_______________________________________
_________________________________________
Postural control
Spatial-temporal coupling between limbs and limb segments
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12. Vision and Motor Control
___________________________________________________________________
Evidence from everyday experiences
Beginning typists look at their fingers
Beginning dancers look at their feet
Evidence from research
The classic “moving room experiment”
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13. _________________________________
Lee & Aronson (1974)
Participants stood in a room in which the walls moved toward or away from them but floor did not move
Situation created a conflict between which two sensory systems?
Vision & proprioception
Results
________________________________________________________________________________________________________________
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14. Neurophysiology of Vision
Basic Anatomy of the Eye
See Figure 6.5 for the following anatomical components
____________________
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15. Neurophysiology of Vision, cont’d
Neural Components of the Eye and Vision
______________ [see Fig. 6.5]
________________
_____________
_____________(cranial nerve II) [Fig. 6.6]
From the retina to the brain’s visual cortex
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16. Techniques for Invesigating the Role of Vision in Motor Control
______________________________
Tracks foveal vision’s “point of gaze”
i.e. “what” the person is looking at
Stop video or film at various times
Spectacles with liquid crystal lenses
_______________________________
Mask view on video or film of specific events or characteristics
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17. Role of Vision in Motor Control
Evidence comes from research investigating specific issues and vision characteristics:
1. Monocular vs. Binocular Vision
__________________________________________________________________________________________________, e.g.
Reaching – grasping objects
Walking on a cluttered pathway
Intercepting a moving object
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18. Role of Vision in Motor Control, cont’d.
2. ________________________________
________________________
Sometimes called foveal vision
Middle 2-5 deg. of visual field
___________________________________________________________________, e.g.
For reaching and grasping an object – specific characteristic info, e.g. size, shape, required to prepare, move, and grasp object
For walking on a pathway – specific pathway info needed to stay on the pathway
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19. Role of Vision in Motor Control, cont’d.
2. Central and Peripheral Vision, cont’d.
___________________________
Detects info beyond the central vision limits
Upper limit typically ~ 200 deg.
_________________________________________________________________________
When we move through an environment, peripheral vision detects info by assessing optical flow patterns
___________________= rays of light that strike the retina
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20. Role of Vision in Motor Control, cont’d.
2. Central and Peripheral Vision, cont’d
Two visual systems
__________________________(central vision)
Anatomically referred to as the ventral stream – from visual cortex to temporal lobe
For fine analysis of a scene, e.g. form, features
Typically available to consciousness
_______________________(peripheral vision)
Anatomically referred to as the dorsal stream – from visual cortex to posterior parietal lobe
For detecting spatial characteristics of a scene and guiding movement
Typically not available to consciousness
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21. Role of Vision in Motor Control, cont’d.
3. ________________________________
As discussed in ch. 5, refers to the “coupling” (i.e. linking together) of a ________________________________
Example of research evidence:
See experiments by Helsen et al. (1998 & 2000) described in textbook
Results show that spatial and temporal characteristics of limb movements occurred together with specific spatial and temporal characteristics of eye movements
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22. Role of Vision in Motor Control, cont’d.
4. Amount of Time Needed for Vision-Based Movement Corrections?
_________________________________________
Researchers have tried to answer this question since original work by Woodworth in 1899
____________________________________________________________________________________________________________________________________________________________________
Expect accurate movement with lights off when no visual feedback needed during movement
Currently, best estimate is a range of 100 – 160 msec. (The typical range for simple RT to a visual signal)
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23. Role of Vision in Motor Control, cont’d.
5. ___________________: The Optical Variable tau
Concerns situations in which:
___________________________________________
__________________________________________________________________________________________
Vision provides time-to-contact object info which motor control system uses to initiate movement
Automatic, non-conscious specification based on changing size of object on retina
At critical size, requisite movement initiated
David Lee (1974) showed the time-to-contact info specified by a mathematically quantifiable optical variable, called tau
Motor control benefit – Automatic movement initiation
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