‘Our integrity sells for so little, but it’s all we really have. It is the very last inch of us. And within that inch, we are free.’ –Alan Moore
Neurons communicate using electrical signals. They transmit these signals to neighboring cells via special contact points known as synapses. When new information needs processing, the nerve cells can develop new synaptic contacts with their neighboring cells or strengthen existing synapses. To be able to forget, these processes can also be reversed. The brain is consequently in a constant state of reorganization, yet individual neurons need to be prevented from becoming either too active or too inactive. The aim is to keep the level of activity constant, as the long-term overexcitement of neurons can result in damage to the brain.
Too little activity is not good either. “The cells can only re-establish connections with their neighbors when they are ‘awake’, so to speak, that is when they display a minimum level of activity”, explains Mark Hübener, head of the study. The international team of researchers succeeded in demonstrating for the first time that the brain is able to compensate even massive changes in neuronal activity within a period of two days, and can return to an activity level similar to that before the change. […]
In their study, they examined the visual cortex of mice that recently went blind. As expected, but never previously demonstrated, the activity of the neurons in this area of the brain did not fall to zero but to half of the original value. […] After just a few hours, they could clearly observe how the contact points between the affected neurons and their neighboring cells increased in size. When synapses get bigger, they also become stronger and signals are transmitted faster and more effectively. As a result of this synaptic upscaling, the activity of the affected network returned to its starting value after a period of between 24 and 48 hours.
photo { John Swannell }
