|Image Source: Jack Tuszynski|
Two University of Alberta physicists and a U.S. colleague may have discovered how memories are encoded in our brains.
Scientists understand memory to exist as strengthened synaptic connections among neurons. However, "components of synaptic membranes are relatively short-lived and frequently re-cycled while memories can last a lifetime," according to the research team of University of Alberta professor Jack Tuszynski, his graduate student Travis Craddock and University of Arizona professor Stuart Hameroff. Their paper, "Cytoskeletal Signaling: Is Memory Encoded in Microtuble Lattices by CaMKII Phosphorylation?", was recently published in the peer-reviewed online journal, PLoS Computational Biology.
The team looked into structures at a deeper molecular level. At the University of Alberta, Tuszynski's group created sophisticated simulations using computational resources made possible by NSERC and the Allard Foundation. They found components that fit together and were capable of creating the information processing and storage capacity that the brain needs to form and retain memory.
The research evaluated possible information inputs to microtubules in the context of brain neuronal memory encoding and long-term potentiation (LTP). A key intermediary in LTP involves the hexagonal holoenzyme calcium-calmodulin kinase II. When activated by synaptic calcium influx, the snowflake-shaped CaMKII extends sets of 6 foot-like kinase domains outward, each domain able to phosphorylate a substrate or not (thus convey 1 bit of information). As CaMKII activation represents synaptic information, subsequent phosphorylation by CaMKII of a particular substrate may encode memory, e.g. as ordered arrays of 6 bits (one ‘byte’). We used molecular modeling to examine feasibility of collective phosphorylation (and thus memory encoding) by CaMKII kinase domains of tubulins in a microtubule lattice.
The practical implications of understanding the mechanism of memory encoding are enormous.
"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," says 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."
University of Alberta Department of Physics News
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