How To Increase Your Frame Rate to 100Hz

The standard frame rate for recordings with Neurophotometrics fiber photometry systems is 40 Hz. This is plenty sufficient for most fiber photometry experiments given the kinetics of the most commonly used fluorescent indicators (e.g. GCaMP). However, if you find yourself wanting to record even faster, you can adjust the camera settings to record up at speeds up to 100 Hz by following this simple procedure.To increase your frame rate, you’ll first need to adjust the field of view of your BlackFly camera. Start by plugging the camera USB cable into a USB-3 port on your computer. Open the FlyCapture software and select “camera” from the devices menu. Before you continue, double check that FlyCapture recognizes the camera as USB 3.0.

From here, click “OK” and navigate to “camera settings” at the top of the toolbar (circled in red).

Under the “Custom Video Modes” tab, change the pixel format to Mono 8.

In the upper left-hand corner, you will see a blue box. Click and drag your cursor within this box to create a smaller red rectangle within that box–this is now your cropped field of view.In the “Image” section, toggle the Left, Top, Width, and Height fields until your cropped field (the red rectangle) is centered within the blue box.

Once the cropped field seems centered, use the FlyCapture viewfinder to check that the entire image from your fiber photometry system is still visible. If it is, click “apply” to save the settings. If not, continue to toggle the cropped field until you can visualize the full image in the viewfinder.

Now that the field of view has been adjusted, the next step is to change the camera’s frame rate. Under the “Camera Settings” tab, check the On/Off box next to the “Frame Rate” sliding scale.Type “100” in the selected field, then uncheck the box. The scale should auto-adjust to the new maximum frame rate.

The final step of this process is to update the code on your driver box. To do this, you first need to download the Arduino IDE if you have not already. Open the file “Drivers_Update.ino” and under the “Sketch” menu, hover over “include library.”If “Button,” “LiquidCrystal,” and “NPM_LCD” are not present at the bottom of this menu, click on “add .zip library” and select each one from the “Libraries” folder included in the “NPM_Drivers_Update_6-2019” folder.

Plug your driver box into your computer using a USB-B to USB-A cable. Select the “Tools” menu, and be sure that the port your driver box is plugged into is selected. On Windows computers, it should be named “COM” followed by a number. On Apple computers, it will probably look something like this:

Finally, click on the arrow next to the check mark, and the code should upload to the driver box. You can now record up to 100 Hz during your experiments!

This post was written by Caroline E. Sferrazza.

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