Nerve cells in the brain possess small protrusions, so called dendritic spines, to communicate with other nerve cells by forming a synapse. These contact sites can be both, short- or long-lived thereby existing for even up to an entire lifetime. Short-lived contact sites reflect an ever- adapting brain, which is necessary to process novel experiences. Long-lived, stable contact sites, on the other hand, form the basis of our memory. But even stable memory content can vary to some extent over time. The basis of this process still remains incompletely understood.