A Three-Dimensional Atlas of the Brain as a Virtual “Reference Work”
For over fifteen years neuroscientists, in collaboration with physicists and engineers from the Institute of Neuroscience and Medicine (INM-1), have been mapping the cerebral cortex and the underlying core regions. Using tissue sections, each of which is twenty-thousandths of a millimetre thick, the researchers record and analyse each individual cell as well as numerous molecules which are used for the transfer of information, and are thus able to draw conclusions about how the brain works.
The scientists analyse the distribution of neurons and use this information to create brain maps. When the maps of several brains are laid on top of each other, probability maps are created, which indicate the probability that a given area of the brain is found in a specific location in the brain. This allows the individual differences between human brains to be taken into account.
As well as examining the spatial layout of the brain, the researchers are also investigating the way in which different regions work together as a system, or in other words, how structure and function are interrelated. For this, they use functional magnetic resonance imaging (fMRI) to show which areas are active during certain activities and under certain impressions.
Two hundred areas have now been documented, corresponding to roughly 70 % of the human brain. Scientists need about a year to analyse an area of the brain. The most recently documented areas are located in the visual cortex and the frontal lobe. The scientists involved estimate that the ambitious project will be completed in about five years.
The three-dimensional brain model will initially help us to better understand the structure and function of the healthy brain. This will subsequently enable physicians to compare the information from the atlas with patient data gained from advanced imaging techniques, for instance magnetic resonance imaging (MRI) or positron emission tomography (PET). The differences between the virtual brain model and individual patient data will provide information about neurological or neurodegenerative diseases such as Parkinson’s, Alzheimer’s or strokes for clinical practice.
Although the atlas of the brain is still in the process of being developed, the existing probability maps can be found in various databases and, together with the software, are available free of charge through the Julich Brain Atlas Viewer on the Forschungszentrum Jülich website.
Institute of Neuroscience and MedicineStructural and functional organisation of the brain (INM-1)