New research has uncovered the molecule that stores long-term memories—it’s called calcium/calmodulin dependent protein kinase, or CaMKII for short.
The discovery of the memory molecule resolves one of the oldest mysteries in neuroscience—how do our brains create and retain long-term memories?
The finding also opens up radically new avenues of brain research. One day, by targeting CaMKII, it may be possible to erase the memories that underlie trauma or drug addiction. Though it would raise serious ethical issues, it might also allow us to change our pasts by wiping out recollections of unhappy experiences.
CaMKII has also been found to play a role in Alzheimer’s disease. It’s never been clear if the illness deletes long-term memories or if they remain present, yet inaccessible to recall. A better understanding of CaMKII might clarify this.
“Just like it’s unimaginable that we could understand cells if we didn’t understand DNA, it’s unimaginable that you can understand memory if you don’t know what molecule stores it,” says John Lisman, chair in neuroscience at Brandeis University, whose lab made the discovery.
A memory may feel abstract or immaterial, but it is actually a biochemical process taking place in the brain. It involves neurons communicating with each other via the “wires” or synapses connecting them.
The pathway an electrochemical signal follows as it continually travels from neuron to synapse to neuron constitutes a memory. Whenever you have that memory, the same pathway gets activated. And the more it’s activated, the more it becomes hardwired into the brain’s circuitry. Eventually, it becomes a long-term memory.
Activation also requires enzymes, molecules that set off chemical reactions. The problem is that these enzymes don’t exist for longer than a week. If a memory is to endure, it would seem that the enzymes would have to remain functioning for years or even decades.
Once the enzymes turn off, one would expect the memories to go with them. “This became a holy grail in neuroscience,” Lisman says. “How can a molecule in your brain serve as a memory? How does nature accomplish this?”