Sources of Sensory Information

1
Sources of Sensory Information
2
2 basic sources

• First from the environment, called exteroception
  (from the outside)
• Second from your body, called interoception
  (comes from inside)

3
Exterceptive Information

• Chief of these sources is your vision
• Defines the physical structure of the environment
• Second of these sources is audition- your hearing
• Very important in sports and activities requiring
  a good sense of sound for direction, speed, etc.,
  and for those who are visually impaired

4
Interoceptive Information

• Also called kinesthetic information
• More relevant to us for motor control
• More commonly called proprioception (from within
  the body)
• Includes information on positions of the joints,
  forces produced by muscles, orientation of the
  body in space

5

• Kinesthesis- sense or awareness we have of
  movements of our joints and muscles during motor
  activity
• Kinesthesis and proprioception are often used
  interchangeably
• This information critical in sports such as
  gymnastics, diving, figure skating- all those
  that require information about how your body
  moves through space

6

• Vestibular apparatus in the inner ear critical to
  posture and balance
• Muscles spindles provide the nervous system with
  information about changes in muscle length
• Golgi tendon organs (junction of muscle and
  tendon) give information about level of force in
  muscle
• Cutaneous receptors are in most skin areas, give
  information about pressure, temperature and touch
  (haptic information)

7
Closed-Loop Control Systems

• How does a heating-cooling system work in your
  home?
• Comparator- (thermostat) senses difference
  between goal and actual room temperature
  (action/no action)
• If an error occurs (action) sends a signal to the
  executive, which is the command or control center
• The executive issues a command to the effector,
  which is responsible for carrying out the action
• Sensory information is carried back to the
  comparator, called feedback, and the loop starts
  over again

8
When do we use this model?

• Driving a car
• Walking
• Sitting
• When else?

9
Conceptual Model

• We have already worked with the information
  processing model
• Stimulus identification, response selection,
  response programming
• This is the executive part of the conceptual
  model
• The motor program in the brain, the spinal cord
  and muscles are the effector- they are the parts
  that carry out the actions

10

• The output- product- performance- provides the
  feedback
• And the comparator is the desired state vs. the
  actual state of performance based on the feedback
• The desired state is determined by the look, the
  sound and the feel of the movement
• When input arrives the desired state is
  determined and represents the feedback you should
  get if you perform the movement correctly

11
Conceptual Model and Continuous Long-Duration
Skills

• Useful for maintaining balance and posture
  (throwing darts, casting a lure, etc.)
• Continuous tracking skills require attending to a
  constantly changing target, such as driving a
  car, running a 10K race- these type of activities
  require using exteroceptive information as well
  as kinesthetic feedback

12
Limitations of Closed-Loop Systems

• Although the system has flexibility in movement
  control and allows for a variety of movement
  options and strategies, its biggest disadvantage
  is that control is very slow particularly in the
  response programming stage. Although you are
  getting feedback, you have to wait for that
  feedback before you can make changes

13
The Conceptual Model
Input
Error
Stimulus Identification
Executive
Response Selection
Response Programming
Desired state
Comparator
Motor Program
Actual state
Effector
Proprioceptive feedback
Spinal Cord
Muscle force, length, joint position, body
position
Muscles
Exteroceptive feedback
Output
Vision, audition