Functional mapping of human medial frontal motor areas - The combined use of functional magnetic resonance imaging and cortical stimulation

Two functional brain-mapping techniques, functional magnetic resonance imag ing (fMRI) and cortical stimulation by chronically implanted subdural elect rodes, were used in combination for presurgical evaluation of three patient s with intractable, partial motor seizures. Brain mapping was focused on ch aracterizing motor-related areas in the medial frontal cortex, where all pa tients had organic lesions. Behavioral tasks for fMRI involved simple finge r and foot movements in all patients and mental calculations in one of them . These tasks allowed us to discriminate several medial frontal motor areas : the presupplementary motor areas (pre-SMA), the somatotopically organized SMA proper, and the foot representation of the primary motor cortex. All p atients subsequently underwent cortical stimulation through subdural electr odes placed onto the medial hemispheric wall. In each patient, the cortical stimulation map was mostly consistent with that patient's brain map by fMR I, By integrating different lines of information, the combined fMRI and cor tical stimulation map will contribute not only to safe and effective surger y but also to further understanding of human functional neuro-anatomy.