MR mapping of the effect of ultrasonic neuromodulation in the amygdala
Keywords
Loading...
Authors
Issue Date
2022-02-22
Language
en
Document type
Journal Title
Journal ISSN
Volume Title
Publisher
Title
ISSN
Volume
Issue
Startpage
Endpage
DOI
Abstract
The possibility to directly but non-invasively modulate neural activity would open up new
horizons for treatment for example for anxiety disorders. This promise can be met by
Transcranial Ultrasonic Stimulation (TUS) with the potential to module plasticity in deep brain
structures non-invasively and induce transient changes outlasting the stimulation. The goal of
this study was to develop MR protocols to enable effective and personalized mapping and
guidance of TUS. Specifically, we advanced state-of-the-art MR skull imaging pipelines and
quantified optimal parameters for accelerated resting-state functional MRI. We focused on the
amygdala, a deep, small brain structure with a well-known functional and structural
connectivity yet out of reach for conventional neuromodulation tools and susceptible to
multiple MR artifacts. To quantify signal specificity, sensitivity, and fidelity of different
protocols we used seed-based connectivity analyses, comparing number of echoes, multiband
acceleration, voxel size, and susceptibility distortion correction methods. Specifically, across
multiple tests, we found that multiband acceleration should be limited to a factor 4, with
multiple echoes benefitting signal-to-noise ratio, where available smaller voxels outperforming
more standard sizes, and spin-echo distortion correction to be preferred over
alternatives. These investigations were targeted at a deep brain region, the amygdala, but our
results show the critical principle of how the inferences that can be drawn are strongly
dependent on the choice of protocol. In fact, well-established features of amygdaloid
connectivity, such as the coupling with subgenual anterior cingulate regions, a critical
biomarker of mental health, are entirely absent in some protocols. These findings highlight the
importance of careful protocol selection in resting-state fMRI.
Description
Citation
Supervisor
Faculty
Faculteit der Sociale Wetenschappen