While researchers tend to focus on the brain's gray matter, half of the brain is actually filled with what is known as white matter.
White Matter and Gray Matter
Gray matter mainly consists of bodies of nerve cells that manage various computations that are responsible for learning, speech, sensation, cognition, and movement.
On the other hand, white matter largely contains axons, which are in-charge of the connectivity between brain cells and the rest of the body.
When it comes to functional magnetic resonance imaging (fMRI), signals from white matter are typically overlooked or discarded altogether due to their weakness and difficulty in spotting. Now, a team of researchers used the exact method to examine white matter changes when participants performed certain tasks.
Brain White Matter Signals
To overcome the challenges that typically came with studying white matter, the study participants were tasked to repeat their actions for a pattern and trend to be built up and measured properly.
It was then observed that there was a clear boost in BOLD signals, which stands for blood oxygenation-level dependent signals, in white matter. This showed that brain activity went up as the tasks were being done. While the exact phenomenon still remains a mystery, this observation is quite important.
Kurt Schilling, a biomedical engineer, explains that they simply know that something is taking place but they do not know the exact meaning of the event. Nevertheless, white matter could truly contain a powerful signal.
When it comes to gray matter, BOLD signal increases indicate greater oxygenation and blood flow within the brain. This might be the same for cells in the brain's white matter. It could possibly signify more oxygen use as the brain works or it might also be linked to activity in gray matter.
Since white matter manages connectivity, it is crucial to know more about the mechanisms behind these observations. Various health conditions, including multiple sclerosis and epilepsy, could emerge when this connectivity ends up breaking down.
Schilling explains that the signal appears to be changing differently across various pathways of white matter. What makes the finding unique as well is that these are all in white matter pathways.
Further research could take a more in-depth focus on these signals of white matter, especially in connection to certain health conditions like Alzheimer's. The researchers also hope to look into the biological causes behind the signals.
Schilling explains that for 25 to 30 years, the other half of the brain has remained neglected. White matter activity has been neglected over the years but this is something that the researchers want to be changed as the future comes. They argue that these signals could be vital brain activity indicators compared to just being background noise.
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