Functional representation on the medial aspect of the frontal lobes in man

✓ Sensorimotor responses to stimulation of the medial frontal and cingulate area were studied in seven unrestrained, unsedated patients who suffered from intractable seizures. Complex postural synergies involving the trunk and proximal extremities appeared contralaterally or occasionally bilaterally. Contraversive turning of head and eyes was not observed. Sensory responses from the supplementary motor area were referred contralaterally and focally; those from the cingulate gyrus were widely referred. Speech impairment from stimulation of the supplementary motor area showed striking similarities with that obtained from stimulation in the frontostriatal region or lateral aspect of the frontal lobe. The observations support the hypothesis that interference with striatal function may be the basis of speech inhibition produced by stimulation of the frontal lobe.

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Preoperative mapping of the supplementary motor area in patients harboring tumors in the medial frontal lobe

Journal of Neurosurgery ◽

10.3171/jns.2002.97.5.1108 ◽

2002 ◽

Vol 97 (5) ◽

pp. 1108-1114 ◽

Cited By ~ 35

Author(s):

Lindsey Nelson ◽

Samir Lapsiwala ◽

Victor M. Haughton ◽

Jane Noyes ◽

Amir H. Sadrzadeh ◽

...

Keyword(s):

Frontal Lobe ◽

Supplementary Motor Area ◽

Motor Area ◽

Neurological Deficits ◽

Motor Deficit ◽

Motor Deficits ◽

Anatomical Landmarks ◽

Content Type ◽

Preoperative Mapping ◽

Fine Print

Object. Injury to the supplementary motor area (SMA) is thought to be responsible for transient motor and speech deficits following resection of tumors involving the medial frontal lobe. Because direct intraoperative localization of SMA is difficult, the authors hypothesized that functional magnetic resonance (fMR) imaging might be useful in predicting the risk of postoperative deficits in patients who undergo resection of tumors in this region. Methods. Twelve patients who had undergone fMR imaging mapping while performing speech and motor tasks prior to excision of their tumor, that is, based on anatomical landmarks involving the SMA, were included in this study. The distance between the edge of the tumor and the center of SMA activation was measured and was correlated with the risk of incurring postoperative neurological deficits. In every patient, SMA activation was noted in the superior frontal gyrus on preoperative fMR imaging. Two speech and two motor deficits typical of SMA injury were observed in three of the 12 patients. The two speech deficits occurred in patients with tumors involving the dominant hemisphere, whereas one of the motor deficits occurred in a patient with a tumor in the nondominant hemisphere. The risk of developing a postoperative speech or motor deficit was 100% when the distance between the SMA and the tumor was 5 mm or less. When the distance between SMA activation and the lesion was greater than 5 mm, the risk of developing a motor or a speech deficit was 0% (p = 0.0007). Conclusions. Early data from this study indicated that fMR imaging might be useful in localizing the SMA and in determining the risk of postoperative deficits in patients who undergo resection of tumors located in the medial frontal lobe.

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