Resting-state white matter-cortical connectivity in non-human primate brain

Area of Science:

• Neuroscience
• Neuroimaging
• Brain Connectivity

Background:

• Functional magnetic resonance imaging (fMRI) commonly analyzes resting-state blood oxygenation level dependent (BOLD) signals in cortical regions.
• Studies on resting-state BOLD signals in white matter are emerging, with unclear biophysical origins but reported correlations with cortical signals.

Purpose of the Study:

• To investigate resting-state connectivity patterns between cortical volumes and white matter bundles in a non-human primate model.
• To validate and interpret findings on white matter BOLD signals and their relationship with gray matter.

Main Methods:

• Utilized a non-human primate model to study resting-state functional connectivity.
• Analyzed correlations between BOLD signals from parcellated cortical volumes and specific white matter bundles.
• Investigated the modulation of these patterns by varying anesthesia levels to alter baseline neural activity.

Main Results:

• Resting-state white and gray matter connectivity patterns are not random and resemble diffusion- and histology-derived anatomic connectivities.
• BOLD correlations between white matter tracts and connected gray matter regions reflect anatomic arrangement and fiber density.
• Increased anesthesia levels weakened correlation coefficients but maintained key connectivity pattern features.

Conclusions:

• Neural activity is detectable by BOLD fMRI in both gray and white matter during the resting state.
• Resting-state BOLD signals in white matter are linked to underlying white matter anatomy.
• Combined gray and white matter functional connectivity may enable refined functional parcellation of the entire brain.