Dendritic Spines: How Memory Is Stored in the Brain

Abstract

Over 100 years ago, Nobel Prize winner Ramon y Cajal first described structures called dendritic spines, located on the surface of brain cells. Since then, scientists have been trying to understand what dendritic spines are and how they function in the brain. Even with the latest technology, it is very difficult to research dendritic spines because they are so tiny—one dendritic spine is about 1/1,000 of a millimeter, and there are thousands of them on the surface of most nerve cells in the brain. Since dendritic spines can change shape and size quickly, some researchers have suggested that they are the structures in the brain where memories are created and stored. This hypothesis is based on hundreds of studies showing that forming a memory causes dendritic spines to undergo major changes in number, size, and shape. Likewise, preventing dendritic spines from changing may stop memories from forming. However, there is still a long way to go before we can identify exactly where memories are kept in the brain. Future studies may help us answer this fascinating riddle.