For years, scientists have studied the molecular basis of memory storage, trying to find the molecules that store memory, just as DNA stores genetic memory.
In an important study published this week in the Journal of Neuroscience, Brandeis University researchers report for the first time that memory storage can be induced and then biochemically erased in slices of rat hippocampus by manipulating a so-called "memory molecule," a protein kinase known as CaMKII.
"The core problem in memory research has been understanding what the storage molecule actually is. Identifying this molecule is essential to understanding memory itself as well as any disease of memory, " explained lead author John Lisman. "With this study, we have confirmed CaMKII as a memory molecule."
The research involved electrically stimulating neuronal synapses to strengthen them, a process known as long-term potentiation (LTP). This process has served as a model system for studying memory. CaMKII has been a leading candidate as a memory molecule because it is persistently activated after LTP induction and can enhance synaptic transmission, properties that are necessary for a memory molecule.
Like a computer whose electronics change with the addition of new information, molecular activity in the hippocampus, where memory is stored in the brain, changes as memory is being stored. In this study, Lisman and his colleagues showed that they could saturate the memory stores. However, when CaMKII was chemically attacked and previous memory erased, it then became possible to insert new memories in the synapses.