Abstracts

Rationale: The negative motor area (NMA) was described in the electrical stimulation study and is considered to have several functions in higher level of motor control; however, its brain network has not been elucidated. This study investigated the networks of the NMA using a combination of electric cortical stimulation and diffusion tensor imaging (DTI).  Methods: Twelve patients with intractable focal epilepsy in which NMA was identified with electrical cortical stimulation were enrolled in this study. Electric stimulation at 50 Hz was applied to the electrodes during motor tasks to identify the NMA. DTI was used to identify the subcortical fibers originating from the NMA found by electrical stimulation.  Results: The NMA was found in premotor areas in all 12 patients (PM-NMA), in pre-supplementary motor areas (preSMAs) in 4 patients (preSMA-NMA) and in posterior parietal cortices (PPCs) in 4 patients (PPC-NMA). DTI detected the fibers connecting to ipsilateral PM, PPC and temporal regions via U-fibers, superior longitudinal fasciculus (SLF) and arcuate fasciculus (AF) from the PM-NMAs. PreSMA-NMA has connection with ipsilateral PM and contralateral preSMA via frontal aslant tract (FAT) and transcallosal commissural fibers, and PPC-NMA with ipsilateral PM via SLF and AF.  Conclusions: This study elucidates the network of the PM-NMA, preSMA-NMA and PPC NMA. Each NMA is involved in the different networks, reflecting different roles on motor control.  Funding: No funding