Brussels, 08 Aug 2006
New research from the Swiss Federal Polytechnic School in Lausanne (EPFL) Brain Mind Institute shows that the brain continually forms new connections following new experiences. The research shows that this process of rewiring can take place in a matter of hours.
While the rapid rewiring of the brain is well known in the developing brain, and scientists are aware that the strength of neuronal connections can vary according to the strength of memories in an adult brain, this kind of continuous rewiring is previously unknown.
The research, published in the journal Proceedings of the National Academy of Sciences, looked at how neurons choose their connections. It reports that neuronal connections switch on and off rapidly, making the overall brain system adaptive, continually altering and changing circuitry.
'The circuitry of the brain is like a social network where neurons are like people, directly linked to only a few other people,' explains co-author Henry Markram. 'This finding indicates that the brain is constantly switching alliances and linking with new circles of 'friends' to better process information.'
The research, carried out on rats, showed that neurons have no particular preference for a specific neuron, and that neurons are ready to make connections with any neuron. They will also make, break and re-make connections rapidly.
The research confirms research published recently by a team from the UK, which found that humans presented with novel images learn more quickly. This research shows a possible dynamic biological basis for that learning. In the experiment, the team excited neuronal samples with glutamate, to mimic the effects of novel experiences, and the rate of reconfiguration increased. This suggests that the brain adapts to new experiences, reconfiguring connections to better respond to a particular situation.
'This continual rewiring of the microcircuitry of the brain is like a Darwinian evolutionary process,' says Dr Markram. 'Where a new experience triggers a burst of new connections between neurons, and only the fittest connections survive.'
The research casts new light onto research into brain function, development and disorder. 'This discovery opens up a whole new frontier for researchers as we now try to understand the evolutionary process that sets the brain on a particular course. Perhaps it could even reveal ways to steer the brain around particular circuitry pathologies such as epilepsy,' he said.