Nerve cells communicate with each other by means of electrical impulses. To create such an impulse, the cells exchange charged ions with their environment. However, the role played by the ever-present chloride channels remained obscure, although some theories predicted a relation between the chloride channel ClC-2 and epilepsy. Scientists are now able to confirm a number of assumptions about the ClC-2 channel and could at last explain why the anticipated epileptic seizures do not occur when nerve cells lack the ClC-2 channels in mice. The results also provide a completely new understanding of how nerve cells may actively influence the exchange of information.