Talairach coordinates

Talairach Coordinates

Cingulate region of the human brain

Talairach coordinates are a three-dimensional coordinate system used to map the human brain. This system is based on the Talairach atlas, which was developed by Jean Talairach and Pierre Tournoux in 1988. The Talairach coordinate system is widely used in neuroimaging to provide a standardized way to describe the location of brain structures.

History

The Talairach coordinate system was introduced as part of the Talairach atlas, which was one of the first comprehensive atlases of the human brain. Jean Talairach, a French neurosurgeon, initially developed the atlas to assist in stereotactic surgery. The atlas was later expanded with the help of Pierre Tournoux to include a more detailed mapping of the brain's anatomy.

Coordinate System

The Talairach coordinate system is based on a set of anatomical landmarks in the brain. The primary reference point is the anterior commissure, a bundle of nerve fibers that connects the two hemispheres of the brain. The coordinate system uses the anterior commissure as the origin (0,0,0) and defines three orthogonal planes:

• The x-axis runs from left to right, with positive values to the right.
• The y-axis runs from posterior to anterior, with positive values towards the front of the brain.
• The z-axis runs from inferior to superior, with positive values upwards.

Applications

Talairach coordinates are extensively used in functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) studies to report the location of brain activity. By using a common coordinate system, researchers can compare results across different studies and subjects.

Limitations

While the Talairach coordinate system has been widely adopted, it has limitations. The original Talairach atlas was based on a single brain, which may not represent the anatomical variability found in the general population. As a result, the Montreal Neurological Institute (MNI) developed an alternative coordinate system that is based on an average of multiple brains, providing a more representative model.

Brodmann areas of the brain

Comparison with MNI Coordinates

The MNI coordinate system is similar to the Talairach system but is based on a template derived from multiple brain scans. This system is often preferred in modern neuroimaging studies due to its better representation of anatomical variability. However, many studies still report results in Talairach coordinates, and conversion tools are available to translate between the two systems.

Related Pages

• Neuroimaging
• Stereotactic surgery
• Functional magnetic resonance imaging
• Positron emission tomography
• Brodmann area