Summary: Scientific research has historically focused on the gray matter of the brain, neglecting the white matter. However, a recent study using fMRI has detected significant brain activity in white matter.
Researchers observed increased BOLD signals throughout the white matter when subjects performed tasks. This discovery challenges conventional beliefs and highlights the importance of white matter in understanding brain disorders.
Key Facts:
- A Vanderbilt University team led by John Gore, Ph.D., used fMRI to identify BOLD signals in white matter, an area that has been little-researched.
- During the study, subjects showed noticeable increases in BOLD signals in white matter across the entire brain when performing tasks.
- These white matter signals are believed to provide valuable insights into brain disorders that disrupt connectivity, such as epilepsy and multiple sclerosis.
Source: Vanderbilt University
The human brain is composed of gray matter—which processes sensation, voluntary movement, and cognition—and white matter, which connects cells and projects to the rest of the body.
In the past, scientists focused mainly on gray matter, assuming that it was more important. However, researchers at Vanderbilt University are now investigating white matter.
Using functional magnetic resonance imaging (fMRI), John Gore, Ph.D., and his team have detected BOLD signals, a marker of brain activity, in white matter.
In a recent study published in the Proceedings of the National Academy of Sciences, the researchers found that BOLD signals in white matter increased throughout the brain when subjects performed tasks during fMRI scans.
These findings are important because disorders like epilepsy and multiple sclerosis disrupt the brain’s connectivity, suggesting that white matter plays a role.
The researchers plan to continue studying white matter signals in schizophrenia, Alzheimer’s disease, and other brain disorders. They also hope to uncover the biological basis for these changes through animal studies and tissue analysis.
In gray matter, BOLD signals reflect increased blood flow and nerve cell activity. It is unclear if the same biological processes occur in white matter or if the signals are related to gray matter activity.
Regardless, the presence of changing signals in white matter is significant. While white matter signals have been understudied due to their lower energy levels, the Vanderbilt researchers have found ways to enhance signal detection.
Previous fMRI studies may have underestimated brain activation and missed crucial information from white matter signals.
About this neuroscience research news
Author: Bill Snyder
Source: Vanderbilt University
Contact: Bill Snyder – Vanderbilt University
Original Research: Closed access.
“Whole-brain, gray, and white matter time-locked functional signal changes with simple tasks and model-free analysis” by Kurt G. Schilling et al. PNAS
Abstract
Whole-brain, gray, and white matter time-locked functional signal changes with simple tasks and model-free analysis
Recent studies have revealed the production of time-locked BOLD functional MRI (fMRI) signals throughout the entire brain in response to tasks, challenging the existence of sparse and localized brain functions and highlighting the pervasiveness of potential false negative fMRI findings.
Several reports have demonstrated reliable detection of BOLD signals in white matter, which have previously been largely ignored.
We demonstrate BOLD signal changes across the whole brain, in both white and gray matter, in response to simple tasks and analyses. Both white and gray matter show time-locked activations across the whole brain, with statistically significant signal changes observed in most tissue types for all task stimuli investigated.
Different regions display different BOLD signal changes to the same task, and each region may exhibit distinct responses to different stimuli. These findings challenge the idea of sparse functional localization and the notion that white matter BOLD signals are artifacts.
