While it’s generally accepted that memories are stored somewhere, somehow in our brains, the exact process has never been entirely understood. Strengthened synaptic connections between neurons definitely have something to do with it, although the synaptic membranes involved are constantly degrading and being replaced – this seems to be somewhat at odds with the fact that some memories can last for a person’s lifetime. Now, a team of scientists believe that they may have figured out what’s going on. Their findings could have huge implications for the treatment of diseases such as Alzheimer's.
Leading the study is Prof. Jack Tuszynski, a physicist from the University of Alberta. Also taking part are his graduate student Travis Craddock, and the University of Arizona’s Prof. Stuart Hameroff.
The project was inspired by an outside research paper, that described experiments in which memories were successfully erased from animals’ brains. That study concluded that a specific protein (calcium-calmodulin dependent kinase complex II, or CaMKII) played a large role in the encoding and erasing of memories, by strengthening or eliminating neural connections.
Tuszynski and his colleagues noted that the geometry of the CaMKII molecule was very similar to that of tubulin protein compounds. These tubulins are contained within microtubule protein structures, which in turn occupy the interiors of the brain’s neurons. They are particularly concentrated in the neurons’ axons and dendrites, which are active in the memory process.
The scientists wanted to understand the interaction between CaMKII, tubulin and microtubules, so based on 3D atomic-resolution structural data for all three protein molecules, they developed highly-accurate computer models. What they discovered was that the spatial dimensions and geometry of the CaMKII and microtubule molecules allow them to fit together. Furthermore, according to the models, the microtubules and CaMKII molecules are capable of electrostatically attracting one another, so that a binding process can occur between them.
This process takes place within the neurons, after they have been synaptically connected, to (in some cases) permanently store memories.
“This could open up amazing new possibilities of dealing with memory loss problems, interfacing our brains with hybrid devices to augment and 'refresh' our memories,” said Tuszynski. “More importantly, it could lead to new therapeutic and preventive ways of dealing with neurological diseases such as Alzheimer's and dementia, whose incidence is growing very rapidly these days.”
A paper on the research was recently published in the journal PLoS Computational Biology.
Source: University of Alberta