Topographic mapping of human motor cortex with transcranial magnetic stimulation: Homunculus revisited

Metman, Leo Verhagen; Bellevich, Jacqueline S.; Jones, Seth M.; Barber, Matt D.; Streletz, Leopold J.

doi:10.1007/bf01234122

Cited by 41 publications

(19 citation statements)

References 21 publications

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“…Additional evidence of recovery was obtained by the TMS study. An MEP with a level of latency compatible with the CST was evoked from the affected hand when stimulating the optimal scalp site of the affected hemisphere [2,13,20]. In the current patient, the above evidence suggests that some portion of the infarcted brainstem other than the CST was responsible for the recovery of motor function, and the main motor function of the affected hand seemed to be controlled by this posterior pathway, which had characteristics similar to those of the CST.…”

Section: Discussionsupporting

confidence: 52%

Motor function reorganization in a patient with a brainstem lesion: DTT, fMRI and TMS study

Jang

Hong

Ahn

et al. 2010

NRE

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Objective: We report on a hemiparetic patient who showed a new motor pathway posterior to the lesion in the midbrain and upper pons, demonstrated by three combined method of diffusion tensor tractography(DTT)/functional MRI(fMRI)/transcranial magnetic stimulation(TMS). Methods: A 21-year-old left hemiparetic male who suffered from tuberous meningitis at the age of 12 months after birth. The evaluations were performed at 20 years after onset. Brain MRI showed focal encephalomalatic lesions due to infarcts in right anterior thalamus, midbrain and upper pons. DTT, fMRI and TMS were performed simultaneously. Results: The contralateral primary sensori-motor cortex was activated during either affected or unaffected hand movements. DTT showed that the motor tracts descended along the known pathway of the CST, with the exception of the motor tract of the affected hemisphere, which descended along the posterior portion to the lesion in the right midbrain and the pons, and then rejoined the CST in the mid-pons. The TMS results suggested that the motor tract of the affected hemisphere had the characteristics of a CST. Conclusion: We believe that the motor function of the affected hand in this patient had been recovered through the pathway posterior to the lesion in the midbrain and upper pons.

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Section: Discussionsupporting

confidence: 52%

Motor function reorganization in a patient with a brainstem lesion: DTT, fMRI and TMS study

Jang

Hong

Ahn

et al. 2010

NRE

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“…We assume, however, that the distortion, which occurs certainly when a 3D map is represented on a 2D coordinate system, is tolerable in the case of the motor cortex. Previous mapping experiments showed that cortical motor representation can be investigated despite the use of a 2D coordinate system [Boroojerdi et al, 1999;Cohen et al, 1991;Foltys et al, 2000;Macdonell et al, 1999;Metman et al, 1993;Wilson et al, 1993]. Furthermore, this technical restriction did not obviously affect the measure of MEP amplitudes, which was highly negatively correlated with the measure of spatial distances.…”

Section: Limitations Of the Studymentioning

confidence: 93%

Transcranial magnetic stimulation and the challenge of coil placement: A comparison of conventional and stereotaxic neuronavigational strategies

Sparing¹,

Buelte²,

Meister³

et al. 2007

Human Brain Mapping

265

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The combination of transcranial magnetic stimulation (TMS) with functional neuroimaging has expanded the potential of TMS for human brain mapping. The precise and reliable positioning of the TMS coil is not a simple task, however. Modern frameless stereotaxic systems allow investigators to base navigation either on the subject's structural magnetic resonance imaging (MRI), functional MRI data, or the use of functional neuroimaging data from the literature, so-called ''probabilistic approach.'' The latter assumes consistency across individuals in the location of task-related ''activations'' in standardized stereotaxic space. Conventional nonstereotaxic localization of brain areas is also a common method for defining the coil position. Our aim was to evaluate the accuracy of five different localization strategies in one single study. The left primary motor cortex (left M1-Hand) was used as target region. Three approaches were based on real-time frameless stereotaxy using information based on either anatomical or functional MRI. The remaining two strategies relied either on standard cranial landmarks (i.e., the International 10-20 EEG system) or a standardized function-guided procedure (i.e., the spatial relationship between the left and right M1-Hand). The results were compared to a TMS-based mapping of the primary motor cortex; center of gravity of motor-evoked potentials (MEP-CoG) was calculated for each subject (n ¼ 10). Our findings suggest that highest precision can be achieved with fMRI-guided stimulation, which was accurate within the range of millimeters. Very consistent results were also obtained with the ''probabilistic'' approach. In view of these findings, we discuss the methods and special characteristics of each localization strategy.

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“…The site of stimulation is less well localized compared with an electrode applied directly to the surface of the brain, so that the effective area of stimulation is larger than that obtained in acute experiments on anaesthetized subjects or animals. However, the centre of the most effective site for stimulation is very similar to that seen during neurosurgery, being slightly anterior to the best points for obtaining responses in muscles of the hand or arm [30,31]. One important difference between the techniques is that, in previous work, the brain has been stimulated with a train of several hundred stimuli at a rate of 50-60 Hz.…”

Section: Organization Of Human Swallowing Motor Cortexmentioning

confidence: 95%

Organization and reorganization of human swallowing motor cortex: implications for recovery after stroke*

Hamdy¹,

Rothwell²,

Aziz³

et al. 2000

Clinical Science

119

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Swallowing problems can affect as many as one in three patients in the period immediately after a stroke. In some cases this can lead to serious morbidity, in particular malnutrition and pulmonary aspiration. Despite this, swallowing usually recovers to a safe level in the majority of patients within weeks. This propensity for recovery is likely to relate to how the swallowing motor cortex is organized and then reorganized after cerebral injury. In this review, we examine present knowledge on the cortical control of swallowing in humans, and examine the aspects of its organization that are important for compensating for recovery after damage. In addition, we examine approaches which may be useful in speeding up the process of recovery. Swallowing may turn out to be a useful model for studying central nervous system plasticity.

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Topographic mapping of human motor cortex with transcranial magnetic stimulation: Homunculus revisited

Cited by 41 publications

References 21 publications

Motor function reorganization in a patient with a brainstem lesion: DTT, fMRI and TMS study

Motor function reorganization in a patient with a brainstem lesion: DTT, fMRI and TMS study

Transcranial magnetic stimulation and the challenge of coil placement: A comparison of conventional and stereotaxic neuronavigational strategies

Organization and reorganization of human swallowing motor cortex: implications for recovery after stroke*

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