The enigma inside our heads — scientists unlock new brain secrets as research deepens
Brain Secrets
French researchers in a study revealed new brain secrets. According to the study, during anxiety, our heart and brain get in touch for a little chat.
Last month, an article was published in Nature Mental Health. This article suggested genetic susceptibility to obesity which impacts the brain physically.
In December 2022, researchers from the US and Germany found that some bacteria in the gut stimulate a gut-brain pathway. This bacteria enhances the effects of dopamine and improves the effects of exercise.
The human brain, an organ that weighs barely 1.3 kg, hides many secrets. However, slowly and surely, some manner of demystification is at play. Just over the last two years, multiple studies into the brain have revealed details that scientists didn’t know before.
Besides, these findings help humans better understand the inside workings of the brain. Apart from this, the findings help unlock clues to neurodegenerative conditions such as Alzheimer’s. Further, which helps in prevention and cure.
Researchers Reviews
In January, for instance, researchers from Harvard Medical School in Boston, in collaboration with other institutes, found that specific mutations in some types of cells speed up more than in others during ageing, providing clues to neuron-degeneration from age and onset of tumors in the brain. This study, however, has not been formally peer-reviewed.
Apart from this, researchers from University of Cambridge are collecting data to analyze human brain with age.
Growth metrics like height and weight, physical development, and even behavioural changes are well-documented as people age. With the help of MRIs, this study attempted to do so for the brain.
The results stimulate that white fluid in the human brain is essential. This fluid is high at the age of 28 and after that it starts declining.
Its grey matter, which is associated with information processing, peaks as early as age 6. Cerebrospinal fluid protects the brain and spinal cord from injury and provides nutrients. This increases until age 2, then plateau until 30, then increase again, growing exponentially in the 60s, the researchers said.
Findings
The findings reveal that neuroimaging can be used as a reference for neurodegenerative disorders, learning disabilities, and brain development.
Learning more about the brain
One of the larger brain studies from the pandemic centred on the creation of a compendium on how the brain ages.
To understand how the brain physically changes as a person ages, researchers studied brain scans of over 101,457 people at all stages of life. The youngest brain in the study was from a 16-week-old foetus, while the oldest was from a 100-year-old.
“The present work proves the principle that building normative charts to benchmark individual differences in brain structure is already achievable at global scale and over the entire life-course; and provides a suite of open science resources for the neuroimaging research community to accelerate further progress in the direction of standardised quantitative assessment of MRI data,” write the scientists in the paper.
Among other things, the study found that the outermost layer of the brain, called the cerebral cortex, which is associated with consciousness and language, reaches its maximum thickness before the age of 2. It is believed that increased cortical thickness is linked to higher intelligence.
It also suggested that the surface area of the brain peaks at about 11 years of age, while the total volume of the cerebrum does so at 12 years.
The Observed Patterns
The observed patterns showed a high degree of stability across individuals, although the authors acknowledged limitations to the findings owing to limitations in MRI data and extreme sensitivity of other instruments.
It also found a number of rapid degenerative changes at older ages, such as increase in the size of ventricles, which hold fluids and are associated with neurodegenerative diseases.
Other parts of the brain were found to change variably as a person grows old, likely depending on daily life and major life experiences. For example, regions of the brain associated with senses reach different levels in different people at different times, the study says, but peak in volume first and fall rapidly as compared to other parts of the brain.
Apart from patterns in grey and white matter and thickness of parts of the brain, the team also found previously unreported neurodevelopmental milestones as the brain ages.
For example, the rate of increase of the total cerebral volume, or the size of the brain, peaks when an adolescent reaches their maximum height.
While, it is well-established that males have larger brain-tissue volumes than females in absolute terms. However, the study found no difference in clinical or cognitive outcomes.
Limitations
The brain and all its neurons are created at birth. However, the development in size and neural networks change over a person’s lifetime, shaped by life experiences.
Recent advancements in the technology of neuroimaging have enabled scientists to document the human brain better. This has led to a slew of discoveries, which are ever-increasing as they build upon each other.
However, several studies have many limitations that the authors highlight.
For example, despite the compendium being the largest dataset of MRI scans, the data was biased towards European and North American ancestry groups, the researchers said.
The data available was also not well-distributed across age groups. The data for fetal, neonatal (newborn), and mid-adulthood (ages 30-40) was lacking. The authors also stressed that their study could not eliminate any bias that existed in the primary studies they evaluated.
