Ableitungen mit Mikroelektroden in den Stammganglien des Menschen

Umbach, W; Ehrhardt, Karl

doi:10.1007/bf00343773

Cited by 7 publications

(2 citation statements)

References 7 publications

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“…Compared to numerous thalamic microelectrode studies, there have been only isolated reports of recordings of human pallidal neurons. In 1965, Umbach and Ehrhardt 32 recorded pallidal single-and multiunit activity using lacquer-insulated microelectrodes with tip sizes of either 1 to 2 m or 20 m. They used a hydraulic microdrive and guide tube assembly adapted to Riechert and Wolff's stereotactic frame 32 and concurrently measured neuronal activity, deep electroencephalography and surface EMG of contralateral leg and shoulder. Studies by Raeva 25 identified units responding to commands to prepare for movement in the lateral segment of GP (GPe) and identified cells with rhythmic oscillations in firing activity in synchrony with limb tremor in the medial segment of GP (GPi).…”

Section: Discussionmentioning

confidence: 99%

Methods for microelectrode-guided posteroventral pallidotomy

Lozano¹,

Hutchison²,

Kiss³

et al. 1996

Journal of Neurosurgery

338

176

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Methods for localizing the posteroventral globus pallidus intermus are described. The authors' techniques include the use of microelectrodes to record single-unit activity and to microstimulate in human pallidum and its surrounding structures. This technique allows a precise determination of the locations of characteristic cell types in sequential trajectories through the external and internal segments of the pallidum. The location of the optic tract can be determined from microstimulation-evoked visual sensations and recordings of flash-evoked potentials. In addition, microstimulation-evoked motor and sensory responses allow the internal capsule to be identified. The data collected using this technique are an important adjunct to selecting optimum sites to place electrocoagulation lesions for stereotactic posteroventral pallidotomy for refractory Parkinson's disease.

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Section: Discussionmentioning

confidence: 99%

Methods for microelectrode-guided posteroventral pallidotomy

Lozano¹,

Hutchison²,

Kiss³

et al. 1996

Journal of Neurosurgery

338

176

View full text Add to dashboard Cite

show abstract

“…Evidencefavoring the idea that the basal ganglia participate in tremor comes from studies by Bergman's group [17,46,47], who reported that GPi neurons oscillate at tremor frequency in MPTP models with both rhesus monkeys and African green monkeys. Neurons with tremor frequency activity in the GPi were found in the early studies of Umbach and Erhardt [48] and Jasper and Bertrand [49]. Although Raeva [ 50] reportedrhythmic oscillations in pallidal neurons in PD, she did not find oscillations associated with the tremor itself.…”

Section: Discussionmentioning

confidence: 98%

Characteristics of oscillatory pallidal neurons in patients with Parkinson's disease

Meng

Zhuang

Hallett

et al. 2020

Journal of the Neurological Sciences

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Background: Excessive neuronal activity in the globus pallidus internus (GPi) is believed to promote parkinsonian akinesia/bradykinesia, but not tremor. Parkinsonian tremor is thought to result from dysfunction in the basal ganglia and cerebello-thalamo-cortical circuits. Whether the GPi is involved in tremorgenesis has not been fully elucidated. This study was designed to quantify the characteristics of oscillatory GPi neurons in patients with Parkinson's disease.Methods: Nine patients undergoing surgery were studied. Microelectrode recordings in the GPi and electromyographic (EMG) activity in the limbs were recorded and the mean spontaneous firing rates (MSFRs) were calculated. Spectral analysis was used to assess neuronal oscillatory patterns. Coherence analysis was applied to explore the relationship between oscillatory neurons and EMG.Results: Of 79 GPi neurons, 50.6% oscillated at the tremor frequency; 25.3% oscillated at β frequency, and 24.1% did not oscillate. The MSFR of all neurons was 81.5 ± 7.4 spikes/s. Among neurons oscillating at tremor frequency, 40% were coherent with the tremor. In four neurons, the pattern changed from tremor frequency to β frequency or vice versa. It appeared that the tremor began before the GPi fired bursts. Conclusion:Some neuronal activity in the GPi correlates with tremor and this correlation might be due to either feedback, maintenance, or initiation. Since there were examples of EMG tremor prior to GPi activity, initiation seems least likely. The data further support the prediction of the classic pathophysiology model of Parkinson's disease.

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Pallidotomy for Tremor

2008

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Summary:We studied tremor-related activity in globus pallidus intcrnus (GPi) neurons and the effects of pallidotomy on tremor in patients with Parkinson's disease. By using microelectrode recording. we identified GPi neurons with rhythmic firing at the frequency of contralateral tremor. There was a strong correlation between the tremor-related neuronal activity and limb tremor ( r = 0.73). The majority of tremor-related neurons were located in the ventral one half of the caudal GPi.the area that is the target for pallidotomy. We found that pallidotomy produced striking improvements in off-period contralateral tremor. These effects were immediate and were maintained for a 2 years. This benefit is obtained despite the progressive nature of the illness and the often reduced dose of medications after surgery. Key Words: Globus pallidus internus-Parkinson's disease-Pallidotomy.Pallidotomy, as first practiced in the early 1950s, was directed toward the control of tremor, but the results were unpredictable and inconsistent.' A large part of this may have been the result of inappropriate target selection within the globus pallidus or the technical difficulties encountered with precise surgical localization with the limitations of the imaging techniques available at that time. Whatever the reason, the results of pallidotomy for tremor were seen as unsatisfactory, and pallidal surgery for tremor was largely abandoned within I decade. Stereotactic surgeons shifted to the motor thalamus and its afferent projections as the preferred target, based on a perceived better alleviation of tremor. With improvements in stereotactic neurosurgery, brain imaging, and with an increased understanding of basal ganglia pathophysiology, it is now appropriate to reevaluate the role of pallidotomy for tremor. Here we examine tremor-related activity of pallidal neurons and describe the effects of unilateral pallidotomy on parkinsonian tremor.

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Ableitungen mit Mikroelektroden in den Stammganglien des Menschen

Cited by 7 publications

References 7 publications

Methods for microelectrode-guided posteroventral pallidotomy

Methods for microelectrode-guided posteroventral pallidotomy

Characteristics of oscillatory pallidal neurons in patients with Parkinson's disease

Pallidotomy for Tremor

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