A Novel Approach to Evaluate Brain Activation for Lower Extremity Motor Control

The purpose of this study was to assess the consistency of a novel MR safe lower extremity motor control neuroimaging paradigm to elicit reliable sensorimotor region brain activity.

Participants completed multiple sets of unilateral leg presses combining ankle, knee, and hip extension and flexion movements against resistance at a pace of 1.2 Hz while lying supine in a 3T MRI scanner. Regions of Interest (ROI) consisted of regions primarily involved in lower extremity motor control (right and left primary motor cortex, primary somatosensory cortex, premotor cortex, secondary somatosensory cortex, basal ganglia, and the cerebellum).

The group analysis based on mixed effects paired samples t-test revealed no differences for brain activity between sessions (P > .05). Intraclass correlation coefficients in the sensorimotor regions were good to excellent for average percent signal change (.621 to .918) and Z-score (.697 to .883), with the exception of the left secondary somatosensory cortex percent signal change (.165).

These results indicate that a loaded lower extremity force production and attenuation task that simulates the range of motion of squatting, stepping, and landing from a jump is reliable for longitudinal neuroimaging applications and support the use of this paradigm in further studies examining therapeutic interventions and changes in dynamic lower extremity motor function.