Two broad findings have been seen in memory reconsolidation, which is the retrieval and strengthening of a recent memory. The first broad finding is that, during memory reconsolidation, changes in translational control — the process of forming new proteins from activated genes — occur in areas of the brain related to memory formation. The second broad finding is that epigenetic mechanisms — various molecular modifications known to alter the activity of genes without changing their DNA sequence — are also somehow actively involved during memory reconsolidation or strengthening.
Now, researchers at the University of Alabama at Birmingham have described a novel mechanism that links epigenetic change to translational control. In the Journal of Neuroscience, they report how several particular epigenetic changes in the hippocampus of the rat brain control downstream regulation of translation in brain neurons during fear memory reconsolidation, acting through a gene called Pten. The downstream target affected by changes in PTEN enzyme levels is the AKT-mTOR pathway, one of the main translation control pathways involved in memory reconsolidation. PTEN was already known to be a potent inhibitor of AKT-mTOR, but was not previously linked to epigenetic control of memory.
“These findings could be critical in treatment of memory disorders, such as post-traumatic stress disorder,” said Farah D. Lubin, Ph.D., associate professor in the UAB Department of Neurobiology. “PTSD is thought to be caused by the lack of extinction of a fear memory. Altering this memory during the reconsolidation process could help in re-associating the memory with a less traumatic context.”
Memory consolidation is the process that stabilizes a memory after it is first acquired in the brain. Memory reconsolidation occurs when that memory is retrieved, and the memory may be modified or strengthened.Paper. (paywall) – Timothy J. Jarome, Gabriella A. Perez, Rebecca M. Hauser, Katrina M. Hatch, Farah D. Lubin. EZH2 Methyltransferase Activity Controls Pten Expression and mTOR Signaling during Fear Memory Reconsolidation. The Journal of Neuroscience, 2018; 38 (35): 7635 DOI: 10.1523/JNEUROSCI.0538-18.2018 More.
This is big if replicated and applicable to humans because managing intolerable memories is an important part of combatting many psychiatric disorders. It also helps answer the question of whether epigenetics really matters much if it only lasts a few generations. If epigenetic changes mess with people’s heads, they could last more than a few generations. They could become culture.
See also: Anthropologist John Hawks is cool to epigenetics shedding light on evolution. Responses like this from a usually level-headed thinker mainly demonstrate that epigenetics is likely to upset quite a few applecarts.
Peter Ward: Epigenetics explains why there are fewer “species” than we think
Epigenetic change: Lamarck, wake up, you’re wanted in the conference room!