Investigating Whole Brain Activation Patterns During Complex Movement Sequences

Voluntary planning and execution of motor sequences rely not just on one brain area but on a distributed motor circuit. This brain-wide network includes both cortical and subcortical regions such as the supplementary motor area (SMA), basal ganglia, and the primary motor cortex (M1). Activity in each of these regions has proven necessary to both motor initiation and execution in both mice and monkeys. Still, technological limits have constrained the ability of previous experiments to simultaneously record activity from multiple brain areas, preventing the extension of these findings to ethologically relevant sequences. As a result of these limitations, prior work has resorted to either simplified movement sequences, such as finger tapping, or highly localized recordings from neural subpopulations. Here, we utilized a novel fMRI recording approach to acquire whole-brain images during a reach-to-grasp task. Using this technique, we were able to acquire motor network activity during both self-initiated and externally cued movement sequences, allowing for the appreciation of unique network signatures associated with either paradigm. These findings both demonstrate the validity of our fMRI method in eliminating movement artifact and shed light on the network dynamics necessary for self-initiated movement generation.