Foot Motion

Lubdha M. Shah, MD

Key Facts

Imaging Anatomy

Foot/ankle movement results in robust activity within cortex about superior termination of central sulcus in paracentral lobule
Supplementary motor activation is seen
- Located in dorsomedial frontal cortex, anterior to leg representation of primary motor cortex
Well-defined somatotopic organization of motor cortex
- Motor area devoted to specific region of cortex is proportional to the number of motor units involved in the region’s control

Design

4-minute block design with visual stimulus presentation &/or “on” and “off” commands
Patient asked to dorsiflex and plantar flex each foot at self-paced rate during “on task” and rest during “off task”
Visual cues can be used to control movement rate
Rate can influence activated area of sensory motor cortex

Preprocessing

Applications

Presurgical motor mapping for lesions in sensorimotor cortex
Some patients with neurological corticospinal deficits may not be able to carry out foot flexion task
Up to 25% of patients exhibit excessive head motion, rendering the task nondiagnostic
SMA and primary motor cortex for lower extremity may lay adjacent to one another; distinguishing the border between the 2 areas can be problematic