Control of Movement experiments

The Role of Muscle Feedback in Motor Performance

In this simulation, called "Proprioceptive feedback", we will examine the role of proprioception, the senses deriving principally from our active muscles (from "muscle spindles" within the body of the muscles) and the tendons which attach them to bones (from "Golgi Tendon organs" within the tendon).

Proprioception means a sense of self not in a psychological sense but in an awareness of the degree and force of muscle contraction that allows our brains to work out the position and movement of the limbs in space.

We will manipulate proprioception by either allowing you to draw objects actively, with your limbs moved under your own control, or passively, with your limbs being moved by someone else thereby reducing or eliminating the proprioceptive feedback from muscle contractions needed to move those limbs.

Instructions

Objective

To determine how feedback from active muscles influences successful recall of motor performance.

General Procedures

The task in this study is the drawing and recall of four-sided irregular shapes.

1. The blindfolded subject is required to draw and then to recall (by drawing) 4-sided irregular closed shapes (i.e., the figure should be of any irregular shape, and start and end points of the figure should meet).
2. The drawings will be done on your computer either passively or actively. The exact condition of either active or passive drawing will vary for each of 8 trials, as listed in the tables below. The subject is required to complete all 8 trials under the conditions listed below:
   • In Active drawing the subject draws a 4-sided irregular closed figure, then closes their eyes and tries to recall the drawing exactly.

     	TRIAL NUMBER	TEST CONDITION
     ACTIVE DRAWING	1	Active drawing #1 + Recall drawing #1
     	2	Active drawing #2 + Recall drawing #2
     	3	Active drawing #3 + Recall drawing #3
     	4	Active drawing #4 + Recall drawing #4

   • In Passive drawing the subject is blindfolded and has someone else move their hand to draw a 4-sided irregular closed figure. While still blindfolded, the subject should actively try to redraw the just-completed drawing by recalling the movements.

     	TRIAL NUMBER	TEST CONDITION
     PASSIVE DRAWING	1	Passive drawing #1 + Recall passive #1
     	2	Passive drawing #2 + Recall passive #2
     	3	Passive drawing #3 + Recall passive #3
     	4	Passive drawing #4 + Recall passive #4

3. The drawings in each trial must not be identical.
4. After each drawing, the experiment asks the subject to actively recall (i.e., to draw by themselves, with their eyes closed) the just-completed drawing, beginning from the same starting point as the original drawing.

Active Drawing

Instructions

1. Press Start to begin the experiment.
2. From any point on the canvas below, draw a closed 4-sided shape by holding down the left mouse button and dragging the cursor. Finish the drawing at the same place you started, then release the left mouse button to complete your shape.
3. With your eyes closed, attempt to redraw your shape exactly as you did the first time. You may open your eyes once complete.
4. Press either Submit Trial to submit your attempt, or Reset Trial to re-attempt the trial.
5. Repeat another 3 times.

Experiment

Passive Drawing

Please note that this experiment requires two people!
We also recommend using a blindfold.

Instructions

1. Press Start to begin the experiment.
2. Move your cursor to the centre of the drawing surface, then close your eyes or put your blindfold on.
3. With your vision obscured, hold down the left mouse button and have your partner move your arm to draw a closed 4-sided shape.
4. Once they have finished drawing the shape, release the left mouse button.
5. With your vision still obscured, attempt to redraw the shape exactly the same as the first time.
6. Press either Submit Trial to submit your attempt, or Reset Trial to re-attempt the trial.
7. Repeat another 3 times.

Experiment

Experimental Results

The results for active and passive drawing are shown in the tables below. An overlay of each drawing and its respective recall drawing has been generated for easier comparison of results.