Strange synchronized brain pulses on EEG using OpenBCI Cyton board I recently received an Open BCI headset, and have been experimenting with it.  One interesting is my brain gives off very regular pulses.  My wife tested the headset too, and she also had these pulses.  I'm not sure if this is some artifact of the headset, or if there is something like a 'brain beat' similar to a heart beat.

Here is an example readout from the headset's 8 channels.



The pulse frequency seems to change based on activity.  Here is another sample after I've been chatting with some people online.  You can see the frequency seems to have doubled, possibly due to increased cognitive load from interaction.

Is there a name for this phenomena, and is there any idea what it is?  



One odd thing about the pulses is that they are synchronized across my brain.  Here is an image of the 8 electrodes placement on my head, which you can see are spread across the top of my head from the front to the back.  

Any idea what can cause the pulses to synchronize like this?



UPDATE: At Bryan Krause suggestion, I looked into whether it is some sort of cardiac pulse.  To get ECG data, I attached two skin patches to my biceps and a ground to my elbow.  The exact same pattern shows up.  I'm guessing it is the electric pulse that drives my heart, but the strange thing is the pulse is much slower than my heart, and does not correspond too closely to my heart rate.  For example, at rest I measured 8 beats per pulse.  Then I did some exercise to elevate my heart rate.  The pulses remained the same frequency but I now had 12 heart beats per pulse.

Here is a shot of the channels.  Channel #1 is the ECG data, and rest of the channels are the EEG.
Turns out these pulses are due to software latency in the OpenBCI GUI.  One particular widget, the headshot widget, uses a lot of the CPU causing packet delay, and leads to the pulse pattern.  Once the headshot widget is turned off, then the pulse artifact disappears.

https://github.com/OpenBCI/OpenBCI_GUI/issues/349