how your brain senses an itch

Sensing the itch

Scratching the Surface of How Your Brain Senses an Itch

I often fail to locate where exactly my skin is itching, and why is it even feeling itchy. We all experience this situation when we feel like the sensors in our skin are not working. However, my skin immediately feels itchy when an insect lands on it.

The question is: why does this happen? And can we prevent it?

The idea of denying a mosquito her morbid satisfaction with my itchy discomfort is very appealing!

Well, this scratching function is an evolution of the sensation function of our body. The neurons in our spinal cord help the brain learn about new functions of the body. Signals between the spinal cord and the neurons tell the body what to do. The sensors pass these signals on to the cord, which then conveys to the receptors which function to perform.

However, a recent study by a scientist, David Acton, shows that in the absence of inhibitory neurons, the neurons in the spinal cord could not connect with a signal and would give the same signal. If it is the “ON” signal, it leads your skin to feel itchy all the time. Until and unless the neurons send the “OFF” signal, the chronic itch would not go away. After further investigation, David Acton figured out that these neurons are the Y1 spinal neurons or the ‘light touch neurons”.

To confirm the findings, Acton and his team introduced an experiment on mice to see whether these neurons act like brakes and accelerators.

By removing the y1 spinal neurons, they checked whether itching levels change. The results showed that in the complete absence of the neuron, the skin didn’t feel the itch at all. Even when the mice were in the presence of ‘light touch’ stimuli, the mice did not scratch.

On the other hand, in the presence of the y1 spinal neurons, the mice would not stop scratching, and anything was considered stimuli by the ‘light touch’ neurons.

What this experiment showed is the y1 spinal neurons do not work in a binary way. The neurons work in a way that prioritizes the ‘light touch’’ stimuli. This could also be the reason why certain people have a longer time span of tolerance to itching than others.

However, this part of the research on the sensing neurons is only half the story. The next part of understanding chronic itch would consider the receptor neurons, as these neurons carry what message the spinal cord has sent to the skin.

When the complete picture of this research shows itself, scientists will be able to formulate drugs and cures for an issue that affects almost 15% of the total population. Once a cure to normal itching is found, we might even get close to finding a solution to the problem of chronic itch.

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