[avaldes]

Not a native English speaker so... what does it mean "cooking up" EEG electrodes?

[brezelgoring]

I presume it means building, "cooking up" is a slang and its meaning varies, it can mean literally cooking, or also processing an idea, or building something. It relates to creation.

[pedalpete]

Somewhat dual meaning, yes it means "building", but we also have to cook them in an oven to cure the materials, so also....literal cooking.