Context

An ‘Indian brain template’ for five distinct age groups as well as a ‘brain atlas’ to help accurate assessment of psychiatric illnesses and conduct neuro-surgical operations have been developed by neuroscientists at the Bengaluru-based National Institute of Mental Health and Neuro Sciences (NIMHANS).

About

• The human brain is highly different in shape and size between individuals and basic demographies.
• It contains hundreds of cortical and subcortical areas with different structures and functions, making it rather challenging to accurately define these areas and map their functions and connections. 
• The human brain is the largest brain of all vertebrates relative to body size.
• The brain makes up about 2 percent of a human's body weight. It weighs about 3.3 lbs. (1.5 kilograms).
  • The average male has a brain volume of 1,274 cubic centimeters.
  • The average female brain has a volume of 1,131 cm3.
• The largest part of the human brain is the cerebrum, which is divided into two hemispheres.
• Underneath lies the brainstem, and behind that sits the cerebellum.
• The outermost layer of the cerebrum is the cerebral cortex, which consists of four lobes:
  • frontal
  • parietal
  • temporal
  • occipital
• Like all vertebrate brains, the human brain develops from three sections-
  • the forebrain develops into the cerebrum and underlying structures
  • the midbrain becomes part of the brainstem
  • the hindbrain gives rise to regions of the brainstem and the cerebellum

Brain template Brain template is a gross representation from various brain images to understand brain functionality in diseased conditions. Brain atlas  A brain atlas is composed of serial sections along different anatomical planes of the healthy or diseased developing or adult animal or human brain where each relevant brain structure is assigned a number of coordinates to define its outline or volume.

Templates for five age groups

• The team has developed five brain templates for age groups ranging from 6 to 60 for both males and females based on the study of nearly 500 brain scans.
• In each of the groups, 41 to 47% of the scans studied are that of females.
• The age groups are divided in the
  • 6-11 years (late childhood)
  • 12-18 years (adolescence)
  • 19-25 years (young adulthood)
  • 26-40 years (adulthood)
  • 41-60 years (late adulthood)
• The idea of studying the scans of brains in various age groups was because “there is a period of remarkable change that occurs from early adolescence to young adulthood (till about 25). It is a process called pruning. The thickness of the cortex starts reducing.
• Till about 5 to 6 years, the size of the brain increases. As exposure to various kinds of environment increases, the grey matter gets pruned, then stabilises and very gradually starts reducing.

Current universal standard

• 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.
  • The MNI was developed by averaging Caucasian brains. Over a period of time, neuroscientists discovered that Caucasian brains are different from Asian brains.
  • The Chinese have their own scale to measure. So do the Koreans and the French, among others.
• The significance of the current study is that neuroscientists need not be dependent upon the current universal standard of using the Montreal Neurological Index (MNI) template.

Significance of the Study

• More precise reference: 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.
• Better understanding: These templates and atlas will also help pool information more usefully in group studies of the human brain and psychological functions, aiding the understanding of psychiatric illnesses like Attention Deficit Hyperactivity Disorder (ADHD), autism, substance dependence, schizophrenia, and mood disorders.