With age, the brain "shrinks"
Using a new method of processing images obtained during magnetic resonance imaging (MRI), Stanford University researchers working under the leadership of Aviv Mezer visualized the process of age-related changes in the human brain. Based on the data obtained in this way, they developed a curve that allows us to assess the nature of maturation and aging of the patients' brains. Its use will facilitate the diagnosis and monitoring of the condition of people with mental illness, developmental delays and other disabilities.
The maturation and aging of the human body is accompanied by visual changes visible to the naked eye. However, until now, no one has had the opportunity to observe the processes taking place in the maturing and aging brain, the volume of which, as it turned out, gradually increases until about 40 years old, after which it slowly begins to decrease. By the end of life, the size of a person's brain roughly corresponds to the size of a 7-year-old child's brain.
Several decades ago, specialists received at their disposal a method of magnetic resonance imaging, which allows visualizing brain tissue and detecting tumors forming in it, as well as evaluating the activity of neurons and its disorders. However, the variability of the method and the subjectivity of the assessment makes it difficult to compare images obtained by different laboratories.
Last year, the authors, who worked as part of an interdisciplinary group of researchers, took part in the development of a technique that allows quantitative comparison of images obtained using different modifications of MRI machines. Subsequently, taking this technique as a basis, they found a way to estimate with a high degree of accuracy the volume of the white matter of the brain, mainly formed by long processes of neurons covered with an insulating myelin sheath necessary for the effective transmission of nerve impulses.
White matter plays a critical role in the development and extinction of the brain. A number of diseases, including schizophrenia and autism, are associated with abnormalities of this component of the brain. Despite the important role of white matter, there has not yet been a measurement system that would allow assessing its compliance with normal indicators.
Having set out to develop such a system, the researchers obtained images of 24 brain regions of 102 people aged 7 to 85 years and used them to create a set of curves showing an increase and subsequent decrease in the volume of white matter in each of the 24 analyzed brain regions during their lifetime.
It turned out that the curves obtained resemble a rainbow in shape: they begin and end at about the same level with the peak occurring between 30 and 50 years. However, the nature of the changes differs for different regions of the brain. Some of them, including those responsible for motor activity, are described by long gentle arcs, the height of which varies little throughout life.
Dynamics of changes in the volume of the white matter of the brain from the age of 7 to the age of 83.
The most affected regions are colored red, and the least affected regions are blue.
At the same time, the curves describing the state of the brain regions responsible for thinking and learning are characterized by steep bends. (The authors note that the minimum age of the study participants was 7 years, which corresponds to a significant level of brain development.)
In the future, researchers plan to study the correlation between the composition of the brain and the learning process, as well as the possibility of using this indicator in the diagnosis of brain diseases, mental retardation and mental disorders.
They have already demonstrated the possibility of identifying patients with multiple sclerosis by the discrepancy between the volume of the white matter of their brain and the indicators of the normal curve. At the same time, deviations from normal indicators in such patients were detected even when analyzing the state of brain regions that do not have visualized changes.
Article by Jason D. Yeatman et al. Lifespan maturation and degeneration of human brain white matter is published in the journal Nature Communications.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on Stanford University materials:
Stanford scientists track the rise and fall of brain volume throughout life.
23.09.2014