February 28th, 2015
Newly published research shows that learning gets more difficult as we age, because we can’t push older memories out of our brains. Research conducted by neuroscientists at the Medical College of Georgia at Georgia Regents University demonstrated that mice with genetically modified brains, made to resemble those of humans in adulthood, had no difficulty forming the kind of strong synaptic connections responsible for learning.
Those same mice, however, proved less able to weaken previously established synaptic connections. This prevents the formation of new, robust, long-term memories.
‘The difference is not how dark the pen is,’ said Dr. Joe Z. Tsien, lead author, ‘But that the newspaper already has writing on it.’
This begs interesting ethical questions about the need to forget older memories. For example, would it be possible to do so without damaging important areas of the brain.
By engineering mice to produce additional quantities of the proteins NR2A and NR2B, scientists were able to mimic the brains of post-pubescent humans. That process was expected to expose test subjects inability to create new, short-term memories.
Brain scans revealed that it was the long-term memories that actually stood in the way of new memory formation.
‘What our study suggests,’ said Dr. Tsien, ‘Is that it’s not just the strengthening of connection, but the weakening of the other sets of connections that creates a holistic pattern of synaptic connectivity that is important for long-term memory formation.’
Intentional memory loss is only fodder for science fiction or unethical human experimentation, now. However, with thanks to this research, science has a better understanding as to what is necessary to create new lasting memories.
Image: Wikimedia Commons
Source: Cui Z, Feng R, Jacobs S, Duan Y, Wang H, Cao X, & Tsien J (2013) Increased NR2A:NR2B Ratio Compresses Long-term Depression Range and Constrains Long-term Memory Scientific Reports, 3 DOI: 10.1038/srep01036