L8A: Sensory Contributions II

Question 1

Answer 1

C

Question 2

Answer 2

Question 3

What are examples of Proprioceptors?

Answer 3

Proprioceptive Receptors and their role in the closed-loop model of motor control

• Muscles: Spindles (Stretch Reflex) & GTO
• Vestibular apparatus
• Cutaneous receptors
• Joint receptors

Question 4

Vision and motor control

Answer 4

Dorsal (and Ventral) streams – non-conscious and conscious vision control

• Patient effects
• Visual illusions
• Optic flow (balance) & tau/time-to-contact

Primacy of vision (compared to other sensory sources of information)

Question 5

What are Muscle spindles?

Answer 5

• Spindle-shaped receptors oriented in
  parallel w/ muscle fibres
• Sensory/afferent neuron (Ia) sends information to spinal cord and can excite motor/efferent neurons to muscle fibres
• Sensitive to changes in length and rate of change in length of muscle fibres

Question 6

Explain

Answer 6

The M1 and M2 responses depict two types of motor reflexes:

• M1 Response (Monosynaptic): This reflex involves a direct, one-synapse connection between the 1a afferent sensory neuron and the motor neuron (MN) in the spinal cord, which then sends a signal to the muscle. It is a simple, rapid response without interneuron involvement.
• M2 Response (Polysynaptic): This response involves more complex processing. The 1a afferent neuron synapses on an interneuron, which may receive descending input from higher brain centers. The interneuron then activates the motor neuron, leading to muscle contraction. This response is slower and more modulated.

Question 7

Summary table to show the 3 types of closed-loop control – with M1 and M2 dependent on spindles

Answer 7

Question 8

Answer 8

B

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Question 9

Proprioceptive reflexive closed-loop control

Answer 9

Question 10

What are GTO = Golgi Tendon Organs?

Answer 10

• Located in junctions between muscle & tendons
• Detect changes in muscle’s tension (force)

Question 11

Proprioceptive reflexive closed-loop control

Answer 11

Question 12

Vestibular apparatus in inner ear. Information
about movements of the head & sense of balance

Answer 12

Question 13

Other receptors in the joints and skin
(in addition to tendons & muscles)

Question 14

4: Cutaneous receptors signal information pertaining to touch, pressure, temperature, pain

Answer 14

Question 15

What are Joint receptors?

Answer 15

Embedded within joint capsules.
Respond to the Limits of joint range & pressure

Question 16

Building out the closed-loop control model of movement execution

Answer 16