Tremor cells in the human thalamus: differences among neurological disorders

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Object. Thalamic neurons firing at frequencies synchronous with tremor are thought to play a critical role in the generation and maintenance of tremor. The authors studied the incidence and locations of neurons with tremor-related activity (TRA) in the thalamus of patients with varied pathological conditions—including Parkinson disease (PD), essential tremor (ET), multiple sclerosis (MS), and cerebellar disorders—to determine whether known differences in the effectiveness of thalamic stereotactic procedures for these tremors could be correlated to differences in the incidence or locations of TRA cells.

Methods. Seventy-five operations were performed in 61 patients during which 686 TRA cells were recorded from 440 microelectrode trajectories in the thalamus. The locations of the TRA cells in relation to electrophysiologically defined thalamic nuclei and the commissural coordinates were compared among patient groups.

The authors found that TRA cells are present in patients with each of these disorders and that these cells populate several nuclei in the ventral lateral tier of the thalamus. There were no large differences in the locations of TRA cells among the different diagnostic classes, although there was a difference in the incidence of TRA cells in patients with PD, who had greater than 3.8 times more cells per thalamic trajectory than patients with ET and approximately five times more cells than patients with MS or cerebellar disorders.

Conclusions. There was an increased incidence of TRA in the thalamus of patients with PD. The location of thalamic TRA cells in patients with basal ganglia and other tremor disorders was similar.

Article Information

Address reprint requests to: Andres M. Lozano, M.D., Ph.D., Division of Neurosurgery, Toronto Western Hospital, 4–447 West Wing, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8. email: lozano@uhnres.utoronto.ca.

© AANS, except where prohibited by US copyright law."

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Figures

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    Correlation between thalamic neuronal activity and tremor. Upper: Trace obtained from a single thalamic unit in a patient with ET, correlating to a trace of arm tremor recorded using an accelerometer (Acc). Lower: Traces showing the correlation between thalamic tremor cell activity in a patient with PD and contralateral arm on EMG recordings.

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    Position of tremor cells relative to the PC and the intercommissural line. Note that TRA cells are located in most of the ventrolateral thalamus, but are primarily centered in the Vim region. A: Patients with PD (431 cells). B: Patients with ET (114 cells). C: Patients with MS (97 cells). D: Patients with cerebellar or posttraumatic tremor (44 cells). Scale: ticks are 2 mm apart.

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    Average location of TRA cells by diagnostic group relative to the PC and the intercommissural line. Parkinson disease is represented by the open circle, ET by the closed square, MS by the closed triangle, and cerebellar and posttraumatic tremor by the open triangle. Scale: ticks are 2 mm apart.

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    Average location of TRA cells by diagnostic group relative to the physiologically defined thalamic borders. Parkinson disease is represented by the open circle, ET by the closed square, MS by the closed triangle, and cerebellar and posttraumatic tremor by the open triangle. Scale: ticks are 2 mm apart.

References

1.

Abosch AHutchison WDSaint-Cyr JAet al: Movement-related neurons of the subthalamic nucleus in patients with Parkinson disease. J Neurosurg 97:116711722002J Neurosurg 97:

2.

Findley LJKoller WC (eds): Handbook of Tremor Disorders. New York: Marcel Dekker1995Handbook of Tremor Disorders.

3.

Hua SELenz FAZirh TAet al: Thalamic neuronal activity correlated with essential tremor. J Neurol Neurosurg Psychiatry 64:2732761998J Neurol Neurosurg Psychiatry 64:

4.

Jankovic JCardoso FGrossman RGet al: Outcome after stereotactic thalamotomy for parkinsonian, essential, and other types of tremor. Neurosurgery 37:6806871995Neurosurgery 37:

5.

Kiss ZHDavis KDTasker RRet al: Kinaesthetic neurons in thalamus of humans with and without tremor. Exp Brain Res 150:85942003Exp Brain Res 150:

6.

Koller WPahwa RBusenbark Ket al: High-frequency unilateral thalamic stimulation in the treatment of essential and parkinsonian tremor. Ann Neurol 42:2922991997Ann Neurol 42:

7.

Lenz FAJaeger CJSeike MSet al: Single-neuron analysis of human thalamus in patients with intention tremor and other clinical signs of cerebellar disease. J Neurophysiol 87:208420942002J Neurophysiol 87:

8.

Lenz FAKwan HCDostrovsky JOet al: Single unit analysis of the human ventral thalamic nuclear group. Activity correlated with movement. Brain 113:179518211990Brain 113:

9.

Lenz FAKwan HCMartin RLet al: Single unit analysis of the human ventral thalamic nuclear group. Tremor-related activity in functionally identified cells. Brain 117:5315431994Brain 117:

10.

Lenz FANormand SLKwan HCet al: Statistical prediction of the optimal site for thalamotomy in parkinsonian tremor. Mov Disord 10:3183281995Mov Disord 10:

11.

Lozano AHutchison WKiss Zet al: Methods for microelectrode-guided posteroventral pallidotomy. J Neurosurg 84:1942021996J Neurosurg 84:

12.

Magnin MMorel AJeanmonod D: Single-unit analysis of the pallidum, thalamus and subthalamic nucleus in parkinsonian patients. Neuroscience 96:5495642000Neuroscience 96:

13.

Nguyen JPDegos JD: Thalamic stimulation and proximal tremor. A specific target in the nucleus ventrointermedius thalami. Arch Neurol 50:4985001993Arch Neurol 50:

14.

Schaltenbrand GBailey P: Introduction to Stereotaxis with an Atlas of the Human Brain. Stuttgart: Thieme1959Introduction to Stereotaxis with an Atlas of the Human Brain.

15.

Schaltenbrand GWahren W: Atlas for Stereotaxy of the Human Brain. Stuttgart: Georg Thieme1977Atlas for Stereotaxy of the Human Brain.

16.

Shahzadi STasker RRLozano A: Thalamotomy for essential and cerebellar tremor. Stereotact Funct Neurosurg 65:11171995Stereotact Funct Neurosurg 65:

17.

Tasker RR: Thalamotomy. Neurosurg Clin N Am 1:8418641990Tasker RR: Thalamotomy. Neurosurg Clin N Am 1:

18.

Tasker RRKiss ZH: The role of the thalamus in functional neurosurgery. Neurosurg Clin N Am 6:731041995Neurosurg Clin N Am 6:

19.

Zirh AReich SGDougherty PMet al: Stereotactic thalamotomy in the treatment of essential tremor of the upper extremity: reassessment including a blinded measure of outcome. J Neurol Neurosurg Psychiatry 66:7727751999J Neurol Neurosurg Psychiatry 66:

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