First MR images to show complete borders in human cerebral cortex

March 31, 2011
High-field MR image of a 25 year old human subject’s brain (field strength 7 Tesla, spatial resolution: 0.6mm). The arrow marks a drop in contrast at the base of the precentral gyrus. The border matches the corresponding border between the primary motor (Brodmann area 4) and somatosensory (Brodmann area 3a) cortex.

Understanding functional properties of the brain’s structural units is one of the main aims of brain research. Until now only fragmentary borders of brain areas could be identified in vivo since the resolution in MR images was not high enough. By using a high-field MRI scanner (field strength of 7 Tesla), a team of researchers led by Stefan Geyer and Robert Turner from the Department of Neurophysics at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig made borders between some areas of the Brodmann map more clearly visible in a living human brain than ever before. More than a century ago, neuroanatomist Korbinian Brodmann subdivided the human cerebral cortex microscopically into structurally different areas. These “Brodmann maps” are used to this day as a classic structural guide to functional units in the cortex in neuroscientific research. This indirect correlation can be somewhat imprecise, however, as no human brain is like another. The technological breakthrough achieved by the research team from Leipzig moves the concept of an individual brain atlas into the realm of possibility.

At the start of the 20th century, Korbinian Brodmann studied the microanatomy of the human , using numerous preparations stained for this purpose, with an optical microscope. Using this technique, he identified around 47 areas in the brain differing in microstructural properties like size, form and packing density of nerve cells. Stefan Geyer, neuroanatomist and research group leader at the Department of Neurophysics at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, says: “Although it is more than a century old, this work remains the gold standard in structural brain maps. It can be found in almost every single textbook on neuroscience.” Researchers later succeeded in assigning different functions to the areas numbered and chartered in a schematic map by Brodmann. For example, area 4 corresponds to the primary motor cortex, area 17 to the visual cortex.

However, several problems arise when an investigator wants to use the map as a structural guide, the scientist states. Activation can so far only be indirectly correlated to the areas. Geyer: “In MR images, we can see the sulcus but not the area’s borders. The resolution of approximately 1 to 2 mm per voxel in MR images has so far not been high enough. Microstructure could only be investigated post-mortem using a microscope – just like a century ago.” It can be very difficult to correctly interpret functional activation without being able to clearly distinguish area borders which can vary from subject to subject.

A new generation of MRI scanners with ultra-high field strength and a possible resolution of under 0.5mm can now solve this problem. Using their ultra-high field 7Tesla MRI scanner, researchers from the Department of Neurophysics succeeded in making the functionally important border between primary motor and somatosensory cortex much more clearly visible in the brains of living volunteers. This achievement opens up a completely new approach in the direction of an individually specific map of the cortex. It is also a first step towards making direct comparisons between microstructure and function in the living human possible.

More information: Stefan Geyer, et al. Microstructural parcellation of the human cerebral cortex - From Brodmann's post-mortem map to in vivo mapping with high-field magnetic resonance imaging Frontiers in Human Neuroscience, 5, Article 19, February 2011.

Related Stories

Recommended for you

Neuroscience research provides evidence the brain is strobing, not constant

November 17, 2017
It's not just our eyes that play tricks on us, but our ears. That's the finding of a landmark Australian-Italian collaboration that provides new evidence that oscillations, or 'strobes', are a general feature of human perception.

Brain activity buffers against worsening anxiety

November 17, 2017
Boosting activity in brain areas related to thinking and problem-solving may also buffer against worsening anxiety, suggests a new study by Duke University researchers.

Investigating patterns of degeneration in Alzheimer's disease

November 17, 2017
Alzheimer's disease (AD) is known to cause memory loss and cognitive decline, but other functions of the brain can remain intact. The reasons cells in some brain regions degenerate while others are protected is largely unknown. ...

Study may point to new treatment approach for ASD

November 17, 2017
Using sophisticated genome mining and gene manipulation techniques, researchers at Vanderbilt University Medical Center (VUMC) have solved a mystery that could lead to a new treatment approach for autism spectrum disorder ...

Neuroscientists find chronic stress skews decisions toward higher-risk options

November 16, 2017
Making decisions is not always easy, especially when choosing between two options that have both positive and negative elements, such as deciding between a job with a high salary but long hours, and a lower-paying job that ...

Paraplegic rats walk and regain feeling after stem cell treatment

November 16, 2017
Engineered tissue containing human stem cells has allowed paraplegic rats to walk independently and regain sensory perception. The implanted rats also show some degree of healing in their spinal cords. The research, published ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.