by Julian Fisher, MD
Those who follow this blog have recently seen some obscured images of Beijing shrouded in smog. I would like to take you to the opposite extreme, clarifying not the world around us but the world within us.
Brain imaging is a rapidly expanding science, something quite familiar to neuroscientists but really quite gee-whiz to everyone else.
Imaging technologies have grown in their power and capabilities so that we can now look at both structure and function within the brain in ways never before dreamed and with detail never expected. The tools that we use are complex. While I could explain them simply, I know that eyes would glaze over worldwide as the words unfolded. So on to the images themselves, with a brief explanation.
Remember that traditional X-rays were able to differentiate hard tissue (bone) from soft tissue (the brain). The newer imaging techniques allow us to see different types of (soft) brain tissue, distinguish pathways, and identify functional areas of the brain--what "lights up" when we listen to music or see a bowl of our favorite potato chips.
Apart from the gee-whiz quotient, there is real value to this advanced imaging. Brain injuries or tumors can distort the normal anatomy of the brain. If you require surgery or radiation therapy, it is crucial that it be directed to the precise area. Knowing how the disease process has distorted the expected, normal anatomy prevents unnecessary injury in the treatment process.
These images (from researchers at the University of California, San Diego) look at the brain from the side, with radiating connections in blue and green.
And from above.
You can see finer detail of connections in this, again visualized from above (from researchers at the University Hospital of Lausanne).
And finally, you can combine functional information (which areas are active with specific tasks or thought processes) with the pathways that serve to connect them (from researchers at Massachusetts General Hospital).
As you see here, the colored splotches indicate functional areas (fMRI, functional magnetic resonance imaging) with connecting pathways added in (from DTI, diffusion tensor imaging) in the central part of the image.
For those of you intrigued by Dr. Oliver Sacks's descriptions of his patients and the ways in which the brain works or does not, this is another way to look at and measure brain function.
These techniques are moving from the experimental to the practical, opening new ways to diagnose and treat brain diseases ... and you may see more of this on your own if you search for terms like "tractography" or"'DTI" or "brain imaging" on the Web.
Julian Fisher, MD is a Boston-based neurologist and medical information entrepreneur.
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