scholarly journals Neuronal Firing Rates and Patterns in the Globus Pallidus Internus of Patients With Cervical Dystonia Differ From Those With Parkinson's Disease

2007 ◽  
Vol 98 (2) ◽  
pp. 720-729 ◽  
Author(s):  
Joyce K. H. Tang ◽  
Elena Moro ◽  
Neil Mahant ◽  
William D. Hutchison ◽  
Anthony E. Lang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Firing Rate ◽  
Globus Pallidus ◽  
Cervical Dystonia ◽  
Neuronal Firing ◽  
Globus Pallidus Internus ◽  
Motor Symptoms ◽  
Firing Rates ◽  
Irregular Pattern

Cervical dystonia (CD) is a movement disorder that involves involuntary turning and twisting of the neck caused by abnormal muscle contraction. Deep brain stimulation (DBS) in the globus pallidus internus (GPi) is used to treat both CD and the motor symptoms of Parkinson's disease (PD). It has been suggested that the differing motor symptoms in CD and PD may arise from a decreased GPi output in CD and elevation of output in PD. To test this hypothesis, extracellular recordings of GPi neuronal activity were obtained during stereotactic surgery for the implantation of DBS electrodes in seven idiopathic CD and 14 PD patients. The mean GPi neuronal firing rate recorded from CD patients was lower than that in PD patients ( P < 0.001; means ± SE: 71.4 ± 2.2 and 91.7 ± 3.0 Hz, respectively). Furthermore, GPi neurons fired in a more irregular pattern consisting of more frequent and longer pauses in CD compared with PD patients. When comparisons were done based on locations of recordings, these differences in firing rates and patterns were limited to the ventral portion of the GPi. In contrast, no difference in firing rate or pattern was observed in the globus pallidus externus between the two groups. These findings suggest that alterations in both firing rate and firing pattern may underlie the differing motor symptoms associated with these two movement disorders.

Internal Pallidal Neuronal Activity During Mild Drug-Related Dyskinesias in Parkinson's Disease: Decreased Firing Rates and Altered Firing Patterns

2007 ◽  
Vol 97 (4) ◽  
pp. 2627-2641 ◽  
Author(s):  
J. I. Lee ◽  
L. Verhagen Metman ◽  
S. Ohara ◽  
P. M. Dougherty ◽  
J. H. Kim ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Firing Rate ◽  
Spike Trains ◽  
Neuronal Firing ◽  
Low Doses ◽  
Significant Group ◽  
Firing Patterns ◽  
Firing Rates ◽  
Before And After

The neuronal basis of hyperkinetic movement disorders has long been unclear. We now test the hypothesis that changes in the firing pattern of neurons in the globus pallidus internus (GPi) are related to dyskinesias induced by low doses of apomorphine in patients with advanced Parkinson's disease (PD). During pallidotomy for advanced PD, the activity of single neurons was studied both before and after administration of apomorphine at doses just adequate to induce dyskinesias (21 neurons, 17 patients). After the apomorphine injection, these spike trains demonstrated an initial fall in firing from baseline. In nine neurons, the onset of on was simultaneous with that of dyskinesias. In these spike trains, the initial fall in firing rate preceded and was larger than the fall at the onset of on with dyskinesias. Among the three neurons in which the onset of on occurred before that of dyskinesias, the firing rate did not change at the time of onset of dyskinesias. After injection of apomorphine, dyskinesias during on with dyskinesias often fluctuated between transient periods with dyskinesias and those without. Average firing rates were not different between these two types of transient periods. Transient periods with dyskinesias were characterized by interspike interval (ISI) independence, stationary spike trains, and higher variability of ISIs. A small but significant group of neurons demonstrated recurring ISI patterns during transient periods of on with dyskinesias. These results suggest that mild dyskinesias resulting from low doses of apomorphine are related to both low GPi neuronal firing rates and altered firing patterns.

Effects of Apomorphine on Subthalamic Nucleus and Globus Pallidus Internus Neurons in Patients With Parkinson's Disease

2001 ◽  
Vol 86 (1) ◽  
pp. 249-260 ◽  
Author(s):  
R. Levy ◽  
J. O. Dostrovsky ◽  
A. E. Lang ◽  
E. Sime ◽  
W. D. Hutchison ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Firing Rate ◽  
Globus Pallidus ◽  
Subthalamic Nucleus ◽  
Current Model ◽  
Passive Movement ◽  
Spontaneous Discharge ◽  
Dopamine Receptor Agonist ◽  
Firing Rates

This study examines the effect of apomorphine (APO), a nonselective D1- and D2-dopamine receptor agonist, on the firing activity of neurons in the subthalamic nucleus (STN) and internal segment of the globus pallidus (GPi) in patients with Parkinson's disease (PD). Single-unit microelectrode recordings were conducted in 13 patients undergoing implantation of deep brain stimulation electrodes in STN and 6 patients undergoing a pallidotomy. Doses of APO (2.5–8 mg) were sufficient to produce anon state, but not intended to induce dyskinetic movements. Following baseline recordings from a single neuron, APO was administered and the activity of the neuron followed for an average of 15 min. The spontaneous discharge of neurons encountered before ( n = 309), during ( n = 146, 10–60 min), and after the effect of APO had waned ( n = 127, >60 min) was also sampled, and the response to passive joint movements was noted. In both nuclei, APO increased the overall proportion of spikes in burst discharges (as detected with Poisson “surprise” analysis), and a greater proportion of cells with an irregular discharge pattern was observed. APO significantly decreased the overall firing rates of GPi neurons ( P < 0.01), but there was no change in the overall firing rate of neurons in the STN ( P = 0.68). However, the mean firing rates of STN neurons during APO-induced movements (choreic or dystonic dyskinesias) that occurred in four patients were significantly lower thanoff-period baseline values ( P < 0.05). Concurrent with a reduction in limb tremor, the percentage of cells with tremor-related activity (TCs) was found to be significantly reduced from 19 to 6% in the STN and 14 to 0% in the GPi following APO administration. APO also decreased the firing rate of STN TCs ( P < 0.05). During the off state, more than 15% of neurons tested (STN = 93, GPi = 63) responded to passive movement of two or more joints. After APO, this proportion decreased significantly to 7% of STN cells and 4% of GPi cells (STN = 28, GPi = 26). These findings suggest that the APO-induced amelioration of parkinsonian symptoms is not solely due to a decrease in overall activity in the GPi or STN as predicted by the current model of basal ganglia function in PD.

Location of Active Contacts in Patients with Primary Dystonia Treated with Globus Pallidus Deep Brain Stimulation

2008 ◽  
Vol 62 (suppl_1) ◽  
pp. ONS217-ONS225 ◽  
Author(s):  
Clement Hamani ◽  
Elena Moro ◽  
Cindy Zadikoff ◽  
Yu-Yan Poon ◽  
Andres M. Lozano
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Deep Brain Stimulation ◽  
Globus Pallidus ◽  
Brain Stimulation ◽  
Cervical Dystonia ◽  
Rating Scale ◽  
Globus Pallidus Internus ◽  
Generalized Dystonia ◽  
Deep Brain

Abstract Objective: Deep brain stimulation of the globus pallidus internus has been used for the treatment of various forms of dystonia, but the factors influencing postoperative outcomes remain unknown. We compared the location of the contacts being used for stimulation (active contacts) in patients with cervical dystonia, generalized dystonia, and Parkinson's disease and correlated the results with clinical outcome. Methods: Postoperative magnetic resonance scans of 13 patients with cervical dystonia, six patients with generalized dystonia, and five patients with Parkinson's disease who underwent globus pallidus internus deep brain stimulation were analyzed. We assessed the location of the active contacts relative to the midcommisural point and in relation to the anteroposterior and mediolateral boundaries of the pallidum. Postoperative outcome was measured with the Toronto Western Spasmodic Torticollis Rating Scale (for cervical dystonia) and the Burke-Fahn-Marsden Dystonia Rating Scale (for generalized dystonia) during the last follow-up. Results: We found that the location of the active contacts relative to the midcom-misural point and the internal boundaries of the pallidum was similar across the groups. In our series, the contacts used for stimulation were clustered in the posterolateral region of the pallidum. Within that region, we found no correlation between the location of the contacts and postoperative outcome. Conclusion: The location of the active contacts used for globus pallidus internus deep brain stimulation was similar in patients with cervical dystonia, generalized dystonia, and Parkinson's disease.

scholarly journals Deep Brain Stimulation Reduces Neuronal Entropy in the MPTP-Primate Model of Parkinson's Disease

2008 ◽  
Vol 100 (5) ◽  
pp. 2807-2818 ◽  
Author(s):  
Alan D. Dorval ◽  
Gary S. Russo ◽  
Takao Hashimoto ◽  
Weidong Xu ◽  
Warren M. Grill ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Basal Ganglia ◽  
Globus Pallidus ◽  
Neuronal Activity ◽  
Firing Pattern ◽  
Neuronal Firing ◽  
Motor Symptoms ◽  
Firing Rates ◽  
Frequency Stimulation ◽  
Motor Thalamus

High-frequency stimulation (HFS) of the subthalamic nucleus (STN) or internal segment of the globus pallidus is a clinically successful treatment for the motor symptoms of Parkinson's disease. However, the mechanisms by which HFS alleviates these symptoms are not understood. Whereas initial studies focused on HFS-induced changes in neuronal firing rates, recent studies suggest that changes in patterns of neuronal activity may correlate with symptom alleviation. We hypothesized that effective STN HFS reduces the disorder of neuronal firing patterns in the basal ganglia thalamic circuit, minimizing the pathological activity associated with parkinsonism. Stimulating leads were implanted in the STN of two rhesus monkeys rendered parkinsonian by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Action potentials were recorded from neurons of the internal and external globus pallidus and the motor thalamus (ventralis anterior, ventralis lateralis pars oralis, and ventralis posterior lateralis pars oralis) during HFS that reduced motor symptoms and during clinically ineffective low-frequency stimulation (LFS). Firing pattern entropy was calculated from the recorded spike times to quantify the disorder of the neuronal activity. The firing pattern entropy of neurons within each region of the pallidum and motor thalamus decreased in response to HFS ( n ≥ 18 and P ≤ 0.02 in each region), whereas firing rate changes were specific to pallidal neurons only. In response to LFS, firing rates were unchanged, but firing pattern entropy increased throughout the circuit ( n ≥ 24 and P ≤ 10−4 in each region). These data suggest that the clinical effectiveness of HFS is correlated with, and potentially mediated by, a regularization of the pattern of neuronal activity throughout the basal ganglia thalamic circuit.

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