I am trying to figure out the connection between an EEG device such as a headband and the external device performing the function. For example, it has been shown people can move cursors on computers by wearing an EEG and blinking. What connects these two technologies? Is the headband set as a microcontroller? Is it a special type of software? If so what are they called?

I read through several academic papers and found out algorithms play a major role in this process. However, I still don’t know what software is being used if any.