Testing Stereo Input on Your Computer
At present, all of our recordings have focused on single channels, where you only have one recording electrode and one ground electrode. You can learn a lot about nervous system function this way, but with (gasp) two channels, you can record the activity of two different parts of the nervous system at the same time! Stay tuned as we work on these experiments and hardware. First, however, you need to see if your laptop has two channels on the line-in. This is not immediately obvious and is often not explicitly stated in the online technical specs of your computer. You need to test it yourself! See video below, and here is an audio file that alternates between the left and right audio channel to help you in your testing.
If you find you do not have stereo input on your computer, you can buy an inexpensive USB two channel input, the "iMic". Note that this USB interface causes a slight 1000 Hz "ring" in your recordings, but you can successfully record spikes with this device, and you can often ground the 1000 Hz ring out.