Did you know that blindness upsets the organization of the cerebral cortex and alters memory?
Losing one sense upsets the others: this is why blind people generally have better senses of smell, hearing, touch and taste than average. Researchers wanted to understand what was the reaction of the brain to the loss of sight and studied the brains of blind mice. The research was carried out within german ruhr university in Bochum.
Immediate brain changes
The scientists observed the mice’s brains just after their blindness began and performed spatial memory tests to assess their memory. They measured the density of neurotransmitter receptors: these are proteins located in the membrane of the neuron that receive neurotransmitters, chemical messengers. The researchers compared this density in blind mice to that of healthy mice. The mice that had just lost their sight had an altered density of neurotransmitter receptors and a deterioration in the plasticity of synapses in the hippocampus. The latter corresponds to the ability of connections between neurons (synapses) to modify their strength according to their function.
The senses adapt
The more the months passed, the more this plasticity was damaged and at the same time, the memory in space was reduced. Over time, neurotransmitter receptors have changed in other areas of the brain, such as the visual cortex, for example. “After blindness, the brain tries to compensate for the loss by increasing its sensitivity to missing visual signals, explains Denise Manahan-Vaughan, who led the study. When this does not work, the other sensory modalities adapt and increase their sensitivity”.
This is not the first blindness study performed on mice. Last March, researchers succeeded in restoring sight to rodents using gold nanoparticles. They are now trying to apply their results to humans to find a way to treat certain eye diseases such as macular degeneration or retinitis pigmentosa.