Brain researchers have observed a dual control system in the hippocampus that contributes to memory and ensures that the brain does not “crash,” as in an epileptic seizure.
The researchers studied the electrical signals that hippocampus nerve cells use to communicate. They found that interneurons inhibit pyramidal cells in two ways: some interneurons receive the same signals as pyramidal cells, so they can control what information the pyramidal cells receive. Other interneurons can only control the pyramidal cells when these want to issue new signals.

One advantage of this dual control mechanism is that the brain can be
continually alert without becoming overloaded, as in epilepsy. During an epileptic seizure, the brain (including the hippocampus) becomes disorganised and all of the pyramidal cells fire signals at the same time.

There are indications that the interneurons in epilepsy patients are
affected, with the result that the pyramidal cells are less well controlled.