How are memories formed and stored in the human brain? This is the overarching question that leads MARINA MIKHAYLOVA’s research. As she explains, there are two important features of memory formation: plasticity and stability of dendritic spines, small protrusions where synapses are formed. Activity-dependent remodeling of the actin cytoskeleton in dendritic spines is essential for synaptic plasticity. This process is triggered by a signal sent from the connected neuron, which results in a calcium influx into the spine. The specific question presented in this video is how initial calcium influx into dendritic spines is connected to actin reorganization. To answer this question the researchers proposed that synapses would need to sense the calcium concentrations. They found that neuronal calcium binding protein caldendrin and filamentous actin-binding protein cortactin are orchestrating direct translation of the initial calcium influx into coordinated rearrangement of spinous actin filaments at the nanoscale in dendritic spines. This novel mechanism could be essential in understanding the pathology of certain synaptic diseases, such as schizophrenia.