How does our mind generate memories and store information? While many neuroscientists believe that memories are jumbles of neurons shaped by experience, one scientist believes that neurons act like LEGO bricks, the building blocks of knowledge.
How is memory created? On the surface level our memories and knowledge are gained through experience. But do the memories gained through such experience simply appear in our brains, or are they constructed there, using some sort of fundamental building block?
Henry Markram at the Swiss Federal Institute of Technology believes the latter is the case.
"We have repeatedly observed how synapses change in response to stimulation and experience," he says, "but the question we were trying to answer was whether this is happening on top of a clean slate or on top of some kind of prearranged organisation."
In order to answer this question, Markham and a team of researchers figured out how to listen to the electrical activity in individual brain cells using needles threaded with wire. Using that charming technique, the team performed more than 200 experiments on a pair of lab rats. They listened to the noise made by groups of 12 neurons, exciting one cell at a time and noting the response from the others in order to determine the shared connections between neurons.
In a brain that was as malleable as most neuroscientists believe, the probability of one neuron being linked to another would be equal. Instead, Markram found the neurons behaved according to something he calls the "common-neighbour rule", more likely to be linked based on shared neighbouring neurons.
More than 2000 simulations were run to predict how virtual brain cells would link together, given this new rule. When the tests were replicated on rats, the results were almost always the same.
The "common neighbour rule" created groups of 40 to 50 linked neurons. These are what Markram calls the "LEGO Blocks" of memory.
"These are the smallest units of the brain that can hold knowledge," he says. "What we need to know now is what kind of knowledge they contain.
This is the first evidence that the basic building blocks of knowledge are built into the brain, rather than gained over time, with experience. Markham suggests these building blocks could also be placeholders, waiting to be filled as we acquire new experience.
If anything it's an interesting new way to look at memory and knowledge. Perhaps one day we'll figure out how to manipulate these blocks, and then we'll all look back at Inception and laugh.
Memory may be built with standard building blocks [New Scientist]