Preclinical Imaging

Detecting Brain Information Direction Flow

Ultra-high Field MRI detects early hemodynamic response

Highly sensitive BOLD fMRI

Detecting brain information direction flow

The use of blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) has greatly enhanced understanding of how the brain functions. Additionally, it provides insights into the functional regions that are connected within brain networks. The timing of signals measurable by BOLD, however, varies depending on which area of the brain is investigated and the type of vessels located therein. It has therefore been claimed that these timings may not truly depict the direction of information flow within the brain. To further understanding of signal processing, researchers at the University of Suwon, Republic of Korea took on the task of determining the direction of information flow. Examining the motor cortex in mice, they performed fMRI with somatosensory as well as optogenetic stimulation. Using a Bruker BioSpec 15.2 Tesla instrument, they were able to detect the early hemodynamic response at microvessels in the proximity of the active neurons. Furthermore, the direction of the information flow was reversed when using somatosensory as opposed to optogenetic stimulation, a result which was expected from known electrophysiology studies and confirmed the early response detection.

The Ultra-high Field Advantage

This work clearly demonstrated that ultra-high field BOLD fMRI is capable of assessing information flow direction. Microvessels near activity sites substantially contribute to the BOLD signal. This contribution increases with linearly increasing field strength for veins. For capillaries, the increase is even supralinear with field strength.

Ultra-high field MRI is needed to obtain the temporal distinction of information flow that can ultimately be used to investigate neural processes on a larger scale, which could play a significant role in the advancement of neuroscience research.

Read the full paper here.