How does the brain react to loss of sight?

Did you know that blindness disrupts the organization of the cerebral cortex and modifies memory?

Losing one's senses upsets others, which is why blind people usually have more developed sense of smell, hearing, touch and taste than average. Researchers wanted to understand what the brain's response to vision loss was and studied the brains of blind mice. The research was conducted at the German Ruhr University in Bochum.

Immediate changes to the brain

Scientists observed the brains of mice just after the onset of their blindness and performed spatial memory tests to evaluate their memory. They measured the density of neurotransmitter receptors: they are proteins located in the neuron's membrane that receive the neurotransmitters, chemical messengers. The researchers compared this density in blind mice to that of healthy mice. Mice that had lost their sight had a modified density of neurotransmitter receptors and a deterioration of the plasticity of synapses in the hippocampus. The latter corresponds to the ability of connections between neurons (synapses) to modify their strength according to the function they have.

The senses adapt

The more the months passed and the more this plasticity was damaged and at the same time, the memory in space was reduced. Over time, neurotransmitter receptors have been modified in other areas of the brain, such as in the visual cortex, for example. "After blindness, the brain tries to compensate for the loss by increasing its sensitivity to the missing visual cues," says Denise Manahan-Vaughan, who conducted the study.When this does not work, the other sensory modalities adapt and increase their sensitivity".

This is not the first study conducted on blindness and performed on mice. Last March, researchers managed to restore the sight of rodents with gold nanoparticles. They are now trying to apply their results to the human to find a way to cure some eye diseases such as macular degeneration or retinitis pigmentosa.

Video: Time and the brain: the illusion of now. Hinze Hogendoorn. TEDxUtrechtUniversity (January 2020).