How HDFT Paints a Picture of The Brain: The Art and Science of HDFT
Well I’m back from Pittsburgh and what a trip it was! I had my brain scanned with Magnetoencephalography (MEG), had a whole battery of neuropsych evaluations, a sleep study monitoring, and I underwent an entire workup for physical, vestibular (balance), and visual health as it relates to the brain (which it all does). A treatment plan was constructed for me, and I have homework to do before my follow-up appointment in six months. But, as I wrote in my last post, the most exciting piece of this trip for me had to do with the state-of-the-art neuroimaging, known as High-Definition Fiber Tracking (HDFT).
In this video, William Bird, Senior Research Assistant and Tractographer at the University of Pittsburgh Learning Research and Development Center, explains how this imaging system allows us to see the pathways that groups of axon fibers follow. Let’s first define a few things so that you can better understand this conversation between me and William.
What is the Brain Made up of?
The primary functional cells of the nervous system are called neurons. Neurons communicate with each other in order to allow us to do just about anything: think, move, see, eat, talk, swallow, smile, breathe, digest food, and essentially everything else that we do. Neurons and their communications are vital to EVERY function of life.
A neuron is a living cell, but unlike other cells, neurons have several projections that come off of their cell body. These projections are like communication lines that connect the brain and body. Let’s think of these like phone lines. While many calls can be received (call waiting, conference calls, etc.) only one call can be sent out.
Dendrites: The many projections that take in phone calls (or nerve pulses) are called dendrites, and the matter in the brain that consists mostly of cell bodies and dendrites is called the grey matter because of it’s color in imaging.
Axon: The one projection that sends/makes phone calls (or nerve pulses) out is called the axon and it tends to group with other lines (like the bunches that travel on telephone poles). The matter that contains mostly axons is called the white matter.
Synapse: The space where one neuron’s axon and another neuron’s dendrite meet is called the synapse. This is where communication between neurons occurs due to the release of neurotransmitters, and it can only occur in the grey matter (where dendrites and cell bodies reside.
* Additional definitions: The central fissure is the line down the middle of the brain that separates the left and right hemispheres.
Ideally, axon fibers complete a pathway all the way to grey matter, or the matter of the brain that consists mostly of cell bodies and dendrites. HDFT identifies groups of axon fibers that are reaching the grey matter as well as axon groups of fibers that quit mid-way and are not reaching grey matter. Unfortunately, HDFT is unable to see axon fibers that are not attempting to create a pathway at all.
Bird and his colleagues are collecting as many HDFT scans of healthy brains (controls) as possible with the intention of creating a clear picture of what a completely healthy brain (with all axons fibers reaching grey matter) looks like. The end goal: being able to spot brain damage to any axon fiber on any brain in the future. A scientific rendering of a perfectly functioning brain would be HUGE, but, as I often say, no two brains are the same. In fact, the wiring of axon fibers in the brain is constantly changing. If we can figure out the similarities or constants between healthy brains, perhaps we can learn to develop a clear treatment plan, just as an Orthopedist doctor follows for setting a broken bone.
I look forward to exploring what this team and it’s technology is capable of uncovering about the brain, brain injury, and neurorehabilitation. I want to thank so many over there at UPitt including David Okonkwo, MD, PhD, Dr. Walter Schneider, Dr. Ryan J. Soose, MD, Dan Pultz, William Bird, Kate Edelman, Tom Hahner, Allison Borrasso, and probably not last and certainly not lease… Bobby. Looking forward to my follow up visit! Until then…
I want to hear from you!
Is this a technology that interests you? What do you think are the possibilities? The limitations? What questions should I bring up in the future? Let me know in the comments.