Evidence of cingulate motor representation in humans Article abstract—A 44-year-old man with a right frontal lobe tumor and intractable seizures underwent subdural grid evaluation before resection. The electrode locations were identified on a three-dimensional surface- reconstructed image of the brain after subdural grid placement. Electrical stimulation of electrodes placed over the right cingulate gyrus revealed evi- dence of tonic posturing of the left forearm and wrist and tonic extension of the left leg. This finding provides further evidence of a motor area in the cingulate gyrus in humans. NEUROLOGY 2000;55:725–728 B. Diehl, MD; D.S. Dinner, MD; A. Mohamed, FRACP; I. Najm, MD; G. Klem, REEGT; E. LaPresto, MS; W. Bingaman, MD; and H.O. Lu ¨ ders, MD, PhD In 1951, Penfield and Welch 1 described the supple- mentary motor area as an area located on the mesial surface of the frontal lobe, anterior to the primary motor area, limited by the cingulate gyrus below and occasionally extending onto the convexity of the cere- bral hemisphere. Stimulation studies in this area have elicited bilateral and contralateral complex movements of extremities with assumption of tonic postures, deviation of head and eyes, vocalizations, and autonomic changes. As sensory responses also have been described, we prefer the term supplemen- tary sensorimotor area (SSMA). 2 Animal data have shown that SSMA-type motor responses could be elicited from the cingulate cortex. 3-5 This has been controversial in humans, 2,6 mostly because the place- ment of the electrodes with respect to the cingulate gyrus could be correlated only indirectly. Three- dimensional reconstruction and direct visualization of the electrodes on MRI now allow definition of the anatomic relationship of the subdural electrodes with more precision. Case report. A left-handed 44-year-old man with intrac- table epilepsy since age 24 years underwent subdural plate evaluation for mapping of seizure onset and electrical stimulation to define eloquent cortex. Seizures were char- acterized by left arm and face jerking. MRI (figure 1) showed a right frontal lobe mass lesion in the superior frontal gyrus extending posteriorly to the precentral sulcus. Neurologic examination revealed brisk deep tendon reflexes on the left with a Babinski sign. Surface video-EEG monitoring showed generalized in- termittent slow waves and a single sharp wave at T7. The EEG seizure pattern was generalized. Invasive recordings. The technical details of insertion of subdural electrode arrays have been discussed previous- ly. 7 Three plates were inserted subdurally: an 8  8 plate over the right lateral convexity, covering the frontal and parietal lobes (A plate), including the lesion on MRI; and a 2  6 grid in the interhemispheric fissure, anterior to the central sulcus. The lower two electrodes (B1 and B7) of this plate covered the cingulate gyrus (B plate; figure 2). A1  6 strip was placed in the interhemispheric fissure (C plate) over the mesial parietal and occipital areas. Interictally, spikes were seen at the anterior margin of the lesion. Seven typical seizures were recorded, all with an initial spike maximum in the superior frontal gyrus, 3 cm anterior to the central sulcus. The intracarotid amytal procedure showed speech rep- resentation in the left hemisphere. Resection of the right frontal lobe with preservation of the precentral gyrus was performed. Since surgery, the patient has experienced rare clonic seizures of the left foot. He has no motor deficit. Pathology revealed a low-grade glioma. Stimulation studies. Stimulation was performed over 2 days using the subdural electrode arrays as described previously 7 and documented on video. The patient was on therapeutic doses of carbamazepine with a level of 9.2 g/dL. Electrical activity in the stimulated and surround- ing electrodes was monitored with an 18-channel GRASS model 8 electroencephalograph (Quincy, MA). The stimula- tion consisted of 5- to 10-s trains of 50-Hz bipolar square- wave pulses of 0.3- to 0.4-ms duration produced by a GRASS S-88 stimulation unit and delivered by a GRASS SIU-7 constant-current isolation unit. The stimulation at each electrode was started at 1 mA and increased by 1-mA increments to a maximum of 15 mA. MRI. Twenty-four hours after the insertion of intra- cranial electrodes, an MRI study was performed using a 1.5 T SP system (Siemens; Erlangen, Germany). Direct coronal magnetization prepared rapid gradient echo (MPRAGE) sequence (flip angle = 10°, inversion time = 300 ms, matrix size = 192  256, field of view = 230 mm) was employed for volumetric acquisition. Three-dimensional volume reconstruction and analysis. Software was developed for interactive surface recon- struction of the brain using real-time volume rendering on a Silicon Graphics Onyx Infinite Reality computer (Moun- tain View, CA). Volume-acquired turbo-fast low-angle shot sequence images were acquired and combined to form a single three-dimensional volume with voxel dimensions of 0.9  0.9  2.0 mm. A triplanar view of the MRI was displayed. The center of the artifact created by platinum electrodes was identified and flagged on the two-dimensional image. A three-dimensional surface-reconstructed image of the brain including the electrode positions previously identi- From the Departments of Neurology (Drs. Diehl, Dinner, Najm, and Lu ¨ d- ers, and G. Klem) and Neurosurgery (Drs. LaPresto and Bingaman), Cleve- land Clinic Foundation, OH; and Department of Neurology (Dr. Mohamed), Royal Institute of Clinical Neurosciences, Royal Prince Alfred Hospital, Camperdown, Australia. Received November 29, 1999. Accepted in final form April 28, 2000. Address correspondence and reprint requests to Dr. B. Diehl, Department of Neurology, Cleveland Clinic Foundation, Desk S51, 9500 Euclid Ave., MB 655, Cleveland, OH 44195; e-mail: diehlb@ccf.org Copyright © 2000 by AAN Enterprises, Inc. 725