Lec 14

Question 1

What happens to proprio if block nerve and cutaneous receptor sensation with anaesthetic? what happened with tendon pulling experiment?

Answer 1

Can still get proprio with only muscle spindles.

In tendon pulling experiment, fingers were held still, but the tendon was pullled creating the illusion of movement via musc spindles.

Question 2

Are joint receptors important in the hand, why/how tested?

Answer 2

Yes (potentially), because they offered a slight advantage in proprioception when inflamed (makes more sensitive) compared to when inhibited.

Question 3

Explain what tests were done to demonstrate the importance of cutaneous receptors in proprio. Is there a way to increase proprioception?

Answer 3

Stretch skin on hands can create illusion of movement.

Can increase proprioception through use of knee brace and shooting sleeves (for basketball). They increase kinesthetic awareness.

Question 4

What probelem is there with muscle spindle proprioception regarding gamma input?

Answer 4

Gamma input can change the firing rate of spindle meaning the same firing rates could mean different lengths depending on the gamma input. Must know the gamma input to get useful info from spindle. (could subtract it out from afferent signals received)

Question 5

corollary discharge

Answer 5

When we move, we also send copy of motor command to sensory centres. Give comparison of intended and actual movement (error detection).

Question 6

How does level of effort during contraction relate to corollary discharge. What does it imply about movement perception

Answer 6

larger amount of effort exerted during contraction lead to increased error in position matching.

Even motor action inhibited (anaesthetics) if people tried really hard to flex hand, gave illusion of hand moving (it wasn’t).

Implies that sense of effort contributes to movement perception. motor (efferent copies) are processed to compare outcome with expected.

Question 7

Ways to block afferent input

Answer 7

Ischemic - block blood flow

Anesthetic - drugs block sensation

Question 8

What did experiments show when removing sensation from skin and joint receptors in hand

Answer 8

Muscle spindles were still able to give accurate proprioception