DNA damage as a learning mechanism
Researchers at MIT's Picower Institute for Learning and Memory discovered that when neurons are stimulated during learning tasks, they deliberately break both strands of DNA at particular genetic locations. These breaks occur in genes that regulate synaptic connections, allowing neurons to rewire themselves. The study, published June 27 in Nature Neuroscience, used high-resolution imaging to observe the process in real time in mouse brain tissue.
Repair process critical for memory
When the researchers blocked the DNA repair mechanism in mice, the animals showed impaired memory formation. "Without the repair, the breaks become permanent damage and the neuron cannot form lasting connections," said lead researcher Dr. Li Wei. The team identified a protein complex called PARP1 as the master regulator that triggers both breakage and repair.
Potential links to neurodegenerative disease
The discovery may have implications for Alzheimer's and other neurodegenerative conditions, where DNA repair mechanisms are known to decline with age. The research team is now investigating whether age-related breakdown of this DNA repair system contributes to cognitive decline.