12-Sep-2020: NIMHANS develops new Indian Brain Templates, brain atlas

A team of neuroscientists from NIMHANS have developed Indian Brain Templates (IBT) and a brain atlas. Neurologists, neurosurgeons and psychiatrists can use it to map the brain structure of their patients and make an accurate assessment.

The neuroscientists studied over 500 brain scans of Indian patients to develop five sets of Indian brain templates and a brain atlas for five age groups covering late childhood to late adulthood (six to 60 years).

The Montreal Neurological Index (MNI) template that we currently use is based on Caucasian brains. The MNI template was made by averaging 152 healthy brain scans from just a small slice of the city’s population in North America. But Caucasian brains are different from Asian brains. While some countries have their own scale to measure the brain, we are still dependent on the Caucasian brain template. What we have developed now is a scale that will measure an Indian brain.

The templates and atlas will provide more precise reference maps for areas of interest in individual patients with neurological disorders like strokes, brain tumours, and dementia. These templates and atlas will also help pool information more usefully in group studies of the human brain and psychological functions, aiding our understanding of psychiatric illnesses like Attention Deficit Hyperactivity Disorder (ADHD), autism, substance dependence, schizophrenia, and mood disorders.

When most brain scans (MRI) are taken, they need to be compared to a standard brain template — a model or standard for making comparisons from a group of individual brain scans. This helps researchers identify parts of the brain. A challenge for researchers is that brain size and shape differs across ages, and across regions and ethnicities, and even greatly within any population.

While the vast majority of these differences are structural and are not associated with intelligence or behaviour, they do present a practical challenge of matching up similar regions across people, which is necessary for accurate measurements. These new population- and age-specific Indian brain templates will allow more reliable tracking of brain development and ageing, similar to how paediatricians monitor a child’s height or weight, for example, using a growth chart.

Although there have been similar attempts previously in India, they were typically focused on young adults and had a significantly smaller number of subjects.

Validation experiments and comparisons with existing international templates found that using the NIMHANS IBTs for Indian brains significantly improved the accuracy of alignment and thereby noticeably reducing distortions, errors or biases in final reports of brain structure and function.

The complete product is freely available for clinicians and researchers across India and the world. The datasets can be freely downloaded from https://hollabharath.github.io/IndiaBrainTemplates . It now requires to be incorporated in normal protocols of brain imaging in India.

29-Oct-2019: IIIT Hyderabad researchers create first ever Indian Brain atlas

Researchers at the IIIT Hyderabad have created the first ever Indian Brain Atlas (IBA). The next step is to prepare atlases for different age groups to study age related effects on brain anatomy.

The average brain size of an Indian was smaller in height, width and volume in comparison to people of the Caucasian and eastern races.

The immediate implication of this finding can be seen in treatment outcomes of neurological problems or brain related ailments - like dementia, Alzheimer’s disease, Parkinson’s disease etc.

Medical practitioners depend on Magnetic Resonance Imaging (MRI) scan to decide on the line of treatment. The references they use are the one’s created by the Montreal Neurological Institute (MNI), based on Caucasian brains.

With the revelations on the Indian brains, the differences in the MRI scans that can emerge by the comparisons (since Indian brains are smaller than Caucasian) can look alarming and lead to misdiagnosis.

The earliest known brain atlas, the Talairach and Tournoux atlas, was created by manually drawing post-mortem brain sections of a 60-year-old French woman.

It was in 1993 that the MNI and the International Consortium for Brain Mapping (ICBM) created the first digital human brain atlas. More recently, MNI and ICBM have released other brain atlases that are widely used as a standard in neuroscience studies. However, these ‘standard’ brain templates created using Caucasian brains are not ideal to analyze brain differences from other ethnicities, such as the Indian population.

MRI images taken are compared with the pre-loaded MNI template to arrive at a diagnosis, and are likely to lead to a misdiagnosis. While even Chinese and Korean brain templates had been constructed, there was no corresponding template constructed for the Indian-specific population.

The first attempt by the IIITH team at creating an Indian-specific brain atlas involved 50 subjects, evenly balanced out across genders. MRI scans of these subjects’ brains were taken at three different hospitals across three different scanners to rule out variations found in scanning machines. Emboldened by the results of the pilot study, the team went on to recruit 100 willing participants in the eventual construction of the Indian Brain Atlas, referred to as IBA 100.

From birth, the brain grows at an alarming rate. But according to most experts, it is around age 20-30, that the brain is said to be fully developed, or ‘mature’. Hence the scans collected were from an equal number of healthy male and female subjects who fell in the age group of 21-30 years, considered as the baseline.

The constructed atlas was validated against the other atlases available for various populations. It was found that the Indian brain on average is smaller in height, width, and volume as compared to the western (MNI) as well as the eastern population (Chinese and Korean).

These differences are found even at the structure level, such as in the volume of the hippocampus and so on. But overall, the IBA 100 is more comparable to the Chinese and Korean atlases than the distant Caucasian one (MNI).

It is desirable to build a larger atlas with a greater heterogeneous mix of subjects to account for diversity, even in terms of educational qualifications. But currently the team’s focus is to understand the aging process itself. There are many changes that take place in a brain due to advancing age, with the most typical one being atrophy or shrinking of structures. In the case of dementia or Alzheimer’s, they are associated with atrophy of the hippocampus.