Secret to lifelong memories sticking is molecular 'glue'

Some memories last a lifetime — and now, scientists have revealed a type of molecular "glue" that helps those memories stick around. 

Memories form when collections of neurons in a region of the brain called the hippocampus activate in response to a particular experience. Each time you recall that experience, the same set of cells activates. When one neuron repeatedly activates another, the connection between those neurons strengthens. 

Over time, this process in the hippocampus, along with related activity in other regions of the brain, solidifies a short-term memory into a long-term one. 

To maintain these long-term memories, brain cells make proteins that help strengthen the connections, or synapses, between neurons. One critical protein is the enzyme PKMzeta, which is continually made by neurons. However, an outstanding question is how this enzyme "knows" to go to the right synapses to ensure that certain memories stay with us forever. 

In a new study, scientists think they've found the answer: an unsung molecule called KIBRA glues the enzyme to strong synapses and also summons new PKMzeta to replace that enzyme when it degrades. The researchers published their findings Wednesday (June 26) in the journal Science Advances. 

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Previous research in humans suggested that different versions of the KIBRA molecule are associated with differences in memory performance, either better or worse. KIBRA was also already known to interact with the PKMzeta enzyme in the hippocampus of mice. So, the scientists behind the new study decided to delve further into that interaction.