Parietal lobe, a potential ally in the fight against Alzheimer’s disease

That the brain is an amazing organ is not a mystery. For the Greek physician and philosopher Hippocrates, this was the “throne” of reason, experience and consciousness, and perhaps he was right. It is the cradle of thought, mind and language. He’s the puppeteer who pulls the strings to make us do things as simple as eating our grandmother’s adorable paella or running to catch the bus. This helps us to distinguish certain sonic qualities of the environment and ultimately allows us to enjoy life.

Unfortunately, nothing lasts forever, and some areas of the brain, such as the parietal lobe, suffer from Alzheimer’s disease. This lobe is responsible for processing mainly somatosensory information, that is, it processes data about touch, movement, and the position of our body in relation to space. In addition, it also processes cognitive and multimodal information (which comes from different sensory modalities).

The parietal lobe is so important that some researchers suggest that decreased blood flow to this area may serve as a biomarker for early detection of Alzheimer’s disease.

Neuroplasticity in vision loss

As we age, the problems following a conversation in a noisy restaurant or detecting a smell or taste become more acute. However, the most well-known sensory deficit that occurs with age is vision loss. It does not hurt to remember that both visual impairment and blindness are problems present at any age and throughout the world.

In people with visual impairments, the parietal lobe does not degrade, but undergoes remodeling as a result of the neuroplastic mechanisms of the brain. These mechanisms are nothing but the ability of the nervous tissue to strengthen its connections and create new ones. It is well known that this neural plasticity can occur after trauma and as a consequence of experience.

Neuroplasticity helps us understand why hours of practice on the organ made Johann Sebastian Bach such a great musician and composer. After all, our brain does not stand still, it is not static, but dynamic.

But why is this happening? What is the reason that the parietal lobes in people with vision loss are like this? neural display? What stimulates you? Well, we should think that visually impaired people have to interact with the environment on a daily basis without the help of their vision. Therefore, they rely more on their sense of touch to recognize objects, they are trained to read Braille texts, and they are able to get around with the use of a white cane.

All of the above will strengthen their neural connections in favor of the parietal lobe. So, it was noticed that in people with visual loss, parietal connections with the occipital lobe are enhanced, which indicates the so-called neuroplasticity.

The role of the parietal lobe in Alzheimer’s disease in a review

There are studies that link vision loss to the onset of Alzheimer’s disease, but they have not been exempted from major methodological limitations. It is here that an alternative hypothesis arises, in which the protagonist, the missing piece of the puzzle, is the parietal lobe.

In our study, published in Journal of Alzheimer’s Diseasewe proceed from the theory that adaptive changes in the nervous system, and in particular in the parietal lobe, may make people with visual functional diversity less susceptible to the occurrence of neurodegenerative diseases associated with the deterioration of this lobe, such as Alzheimer’s disease.

This hypothesis could be a breakthrough in understanding both Alzheimer’s disease and the brain changes that follow vision loss. Well, not only is it important to explore therapeutic treatments for neurodegenerative diseases, but it is also interesting to understand their pathophysiology. Thus, it remains in the hands of science to uncover this unknown and tip the scales in favor or against the proposed hypothesis.

This article was previously published by the Office for the Transfer of Research Results (OTRI) of the Complutense University of Madrid (UCM).

Monika Alba Ahullo Fuster, Postgraduate and Research Fellow, Department of Radiology, Rehabilitation and Physiotherapy / Faculty of Nursing, Physiotherapy and Podiatry, Complutense University of Madrid

This article was originally published on The Conversation. Read the original.