The overall goal of this protocol is to introduce the application of a bouncing ball with uniformly varying velocity in a metronome synchronization task. This method can help answer key questions in the field of sensory motor synchronization and timing processing, such as whether sensory motor synchronization is modality specific. The main advantage of this technique is that synchronization of the introduced visual bouncing ball is comparable to synchronization of auditory tones.

Demonstrating the procedure will be Liying Zhan, a grad student from our laboratory. Begin by asking the subject to sit in front of a computer screen with a 60 centimeter viewing distance and have them put on a headset. Provide the subject with a written informed consent form to sign, followed by the experimental instructions explaining the metronome synchronization task.

Next, open the experimental software on the computer. Start a practice session to allow the subject to become familiar with the 600 millisecond inter-onset interval or IOI sequences. After the subject has completed the practice trials, instruct them that the experimental session will begin next.

Next, type Bouncingball_run with the AT parameters in the Command window and then press the Enter key to begin the 600 millisecond IOI AT sequence. Watch the subject tap on a keyboard key using the index finger in synchrony with the tones in the AT sequence. Next, type Bouncingball_run with the VF parameters in the Command window and then press the Enter key to begin the 600 millisecond IOI VF sequence.

Watch the subject tap on a keyboard key using the index finger in synchrony with the flashing balls. Lastly, type Bouncingball_run with the VB parameters in the Command window and then press the Enter key to begin the 600 millisecond IOI VB sequence. Watch the subject tap on a keyboard key using the index finger in synchrony with the moments when the bouncing ball moves to the lowest position.

Finally, repeat each of the AT VF and VB sequences with a 900 millisecond IOI. After the subject has completed the experiment, thank them for their time and escort them out of the testing room. The results from this experiment indicated that for both 600 millisecond and 900 millisecond IOI's, the synchronization of the bouncing ball was much more stable then synchronization of visual flashes.

Further, the stability of the bouncing ball was not less stable than synchronization of auditory tones. When attempting this procedure, it's important to remember that the usage of bouncing balls should be limited for IOI's longer than 300 milliseconds because the bouncing ball is a 300 milliseconds IOI is unnaturally fast to tap. After its development, this technique paved the way for researchers in the field of sensory motor synchronization and timing processing to explore the coordination of timing in the sensory and motor cortices.

After watching this video, you should have a good understanding of how to carry out the synchronization task by employing the bouncing ball with a uniformly varying velocity.