Strange synchronized brain pulses on EEG using OpenBCI Cyton board
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