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Functional ultrasound imagingBrain-wide networks Functional connectivity Dynamic functional connectivity Neuroimaging Systems neuroscience Behavior
Abstract:
Functional ultrasound (fUS) is a hemodynamic-based functional
neuroimaging technique, primarily used in animal models, that combines a
high spatiotemporal resolution, a large field of view, and compatibility
with behavior. These assets make fUS especially suited to interrogating
brain activity at the systems level. In this review, we describe the
technical capabilities offered by fUS and discuss how this technique can
contribute to the field of functional connectomics. First, fUS can be
used to study intrinsic functional connectivity, namely patterns of
correlated activity between brain regions. In this area, fUS has made
the most impact by following connectivity changes in disease models,
across behavioral states, or dynamically. Second, fUS can also be used
to map brain-wide pathways associated with an external event. For
example, fUS has helped obtain finer descriptions of several sensory
systems, and uncover new pathways implicated in specific behaviors.
Additionally, combining fUS with direct circuit manipulations such as
optogenetics is an attractive way to map the brain-wide connections of
defined neuronal populations. Finally, technological improvements and
the application of new analytical tools promise to boost fUS
capabilities. As brain coverage and the range of behavioral contexts
that can be addressed with fUS keep on increasing, we believe that
fUS-guided connectomics will only expand in the future. In this regard,
we consider the incorporation of fUS into multimodal studies combining
diverse techniques and behavioral tasks to be the most promising
research avenue.