MRI Setup

Checklist

Before leaving for the MRI Center, ensure you have the following:

• Experimenter Laptop (check that you know its whereabouts prior to the scan date!)
• Physical experimental stimuli (if any)
• Contact information for all participants for that day

Upon Arrival

Empty your pockets of anything metallic

Test the Experiment Script

Before we check that the buttons and AV display should be working fine, we should do a dry run of the experiment script to make sure that you are familiar with running it. We wish to avoid having participants waiting uncomfortably in the scanner while we troubleshoot our scripts!

1. Open a terminal window (if one is not already open) and navigate to the directory containing the script to be run that day
   • The script is likely to be found in a subdirectory under ~/Experimenter/Documents/MATLAB/
2. Launch MATLAB

ptb3-matlab

1. Run the script, using a dummy subject ID (e.g., 9999)
2. Our fMRI experiments usually listen for events from the external keypad
   • If the external USB keyboard has not yet been connected, the scripts will default to listening to the laptop keyboard
   • We simulate the scanner room events by pressing the laptop keyboard buttons:
     • A laptop keypress of '6' simulates a scanner trigger (the experiments often wait for this trigger signal to synchronize the experiment with the scanner)
     • Keypresses of 1, 2, 3 or 4 simulate the participant button box responses (see below), which you might need to do if the experiment waits on participant responses

Experimenter Laptop Setup

The laptop connects via USB to the Lumina console. The console masquerades as an external USB keypad and sends participant keypresses and scanner trigger events to the laptop.

Connect the Lumina console to the laptop

1. Locate the white USB cable in the back of the Lumina console
2. Plug the other end into a USB port in the laptop

Check that the keypad is sending signals to the laptop

Before you enter the Magnet area, ensure that you are metal free!

1. Set the Lumina controller to send the expected signals
   • The Controller Mode should be set "As Keyboard"
   • Toggle the Using to E-Prime
2. Find the two 2-button response boxes are in the scanner room
   • They are likely to be found attached to the wheeled display mount stand
   • If they are not attached, ask the technician for help setting them up
   • Examine the button boxes closely. You will see they are labeled L (blue/yellow) and R (red/green)
3. Log in as the experimenter on the laptop
4. Open a terminal window
5. Navigate to the directory containing the Keyboard test script
6. Launch MATLAB

ptb3-matlab

1. Run the keyboard test script

>>keyboard_info

1. • The script will give you a number of potential keyboards to test out. Select Cedrus Corporation Lumina Keyboard
   • One of the experimenters should press each of the keypad buttons while the other monitors that the button presses are registering in MATLAB
   • If the Lumina box is configured correctly to send E-Prime signals, the key-presses should be showing up as the numbers 1 to 4 (the scanner trigger will register as a ^6)
2. Troubleshoot if necessary, because running the experiment will absolutely depend on the external USB keyboard being configured

Display Setup

1. An HDMI cable (Amazon.com branded) should be poking up through the desk. Connect it to the HDMI port on the laptop (there is only one port that this cable can possibly fit into)
2. Participants will typically be looking at stimuli presented on a display positioned at the head of the scanner
3. Ensure that the stimuli are projected in the correct orientation
   • • Because they are looking through a mirror, the image will have to be flipped horizontally
     • Depending on the mirror attached to the head coil, the image may also need to be flipped vertically
     • The SensaView display control box has a series of 4 toggle buttons that control the display
     • The most likely orientation is marked with a piece of tape on the SensaVue control box. Double-check with the scanner technician to confirm
       • The 16-channel head coil requires the image to be LR flipped; the 32-channel coil requires the image to be LR and TB flipped

Audio Setup

We have not yet run an experiment with auditory stimuli, so this is not yet sorted. However a sketch of the procedure will entail playing a test script that presents some auditory items, and having one of the scan team listen over the MRI headphones while the other runs the script.

Troubleshooting

• Whether or not the external keyboard is plugged in at the time that you launch MATLAB seems to dictate whether or not MATLAB will see it
  • If you are finding that the keyboard check script is not detecting the external USB keypad, relaunch MATLAB, ensuring that the USB keypad is plugged in when MATLAB is launched
• If all else fails, reboot the laptop