Brain zaps are sensory disturbances that can feel like shock sensations in the brain. A person may also notice a brief buzzing sound and feel faint or black out momentarily ( I have never blacked out). My eyes seem to automatically close and I see bright lights and patterns in my field of vision. The zap only lasts for a few seconds but keeps repeating for a length of time. It seems that each time it happens it can be a little different, like the zap may be followed by a flushing feeling in your body that fades.
I know this is so freaky strange that it is hard to believe but believe me it happens. The not knowing what or why is terrible and scary.