scholarly journals Effects of High-Frequency Stimulation in the Internal Globus Pallidus on the Activity of Thalamic Neurons in the Awake Monkey

2003 ◽  
Vol 89 (2) ◽  
pp. 1150-1160 ◽  
Author(s):  
Marjorie E. Anderson ◽  
Nadia Postupna ◽  
Mark Ruffo
Keyword(s):  
Globus Pallidus ◽  
High Frequency ◽  
Internal Capsule ◽  
High Frequency Stimulation ◽  
Burst Frequency ◽  
Thalamic Neurons ◽  
Internal Globus Pallidus ◽  
Current Spread ◽  
Frequency Stimulation ◽  
Similar Intensity

The reduction in symptoms of Parkinson's disease produced by high-frequency stimulation (HFS) in the internal globus pallidus (GPi) has been proposed to be due to stimulus-induced inactivation of pallidal neurons and resulting disinhibition of thalamic neurons. We tested this in awake Macaca fascicularis by stimulating between pairs of electrodes inserted into GPi under electrophysiological control and recording the responses evoked in thalamic neurons. HFS produced a reduction, not an increase, in discharge frequency during the stimulus train in 77% of the responsive thalamic neurons. Only 16% of the responsive cells showed an increase in discharge during stimulation and, for some of these, stimulation at a similar intensity produced contralateral muscle contraction, a probable sign of current spread to the internal capsule. The few thalamic neurons studied during bursting had a reduction in burst frequency and duration during HFS. We conclude that high-frequency stimulation within GPi does not necessarily facilitate thalamic discharge, and it may act, instead, to interrupt abnormal patterns of thalamic discharge associated with parkinsonian symptoms.

Frequency-dependent effects of electrical stimulation in the globus pallidus of dystonia patients

2012 ◽  
Vol 108 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Liu D. Liu ◽  
Ian A. Prescott ◽  
Jonathan O. Dostrovsky ◽  
Mojgan Hodaie ◽  
Andres M. Lozano ◽  
...  
Keyword(s):  
Globus Pallidus ◽  
High Frequency ◽  
Gaba Release ◽  
Neuronal Firing ◽  
High Frequency Stimulation ◽  
Low Frequencies ◽  
Clinical Benefits ◽  
Frequency Stimulation ◽  
Train Length ◽  
Additional Support

Deep brain stimulation (DBS) in the globus pallidus internus (GPi) has been shown to improve dystonia, a movement disorder of repetitive twisting movements and postures. DBS at frequencies above 60 Hz improves dystonia, but the mechanisms underlying this frequency dependence are unclear. In patients undergoing dual-microelectrode mapping of the GPi, microstimulation has been shown to reduce neuronal firing, presumably due to synaptic GABA release. This study examined the effects of different microstimulation frequencies (1–100 Hz) and train length (0.5–20 s), with and without prior high-frequency stimulation (HFS) on neuronal firing and evoked field potentials (fEPs) in 13 dystonia patients. Pre-HFS, the average firing decreased as stimulation frequency increased and was silenced above 50 Hz. The average fEP amplitudes increased up to frequencies of 20–30 Hz but then declined and at 50 Hz, were only at 75% of baseline. In some cases, short latency fiber volleys and antidromic-like spikes were observed and followed high frequencies. Post-HFS, overall firing was reduced compared with pre-HFS, and the fEP amplitudes were enhanced at low frequencies, providing evidence of inhibitory synaptic plasticity in the GPi. In a patient with DBS electrodes already implanted in the GPi, recordings from four neurons in the subthalamic nucleus showed almost complete inhibition of firing with clinically effective but not clinically ineffective stimulation parameters. These data provide additional support for the hypothesis of stimulation-evoked GABA release from afferent synaptic terminals and reduction of neuronal firing during DBS and additionally, implicate excitation of GPi axon fibers and neurons and enhancement of inhibitory synaptic transmission by high-frequency GPi DBS as additional putative mechanisms underlying the clinical benefits of DBS in dystonia.

scholarly journals Response of Human Thalamic Neurons to High-Frequency Stimulation

PLoS ONE ◽  
2014 ◽  
Vol 9 (5) ◽  
pp. e96026 ◽  
Author(s):  
Merrill J. Birdno ◽  
Wei Tang ◽  
Jonathan O. Dostrovsky ◽  
William D. Hutchison ◽  
Warren M. Grill
Keyword(s):  
High Frequency ◽  
High Frequency Stimulation ◽  
Thalamic Neurons ◽  
Frequency Stimulation

scholarly journals Evoked transients of pH-sensitive fluorescent false neurotransmitter reveal dopamine hot spots in the globus pallidus

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Jozsef Meszaros ◽  
Timothy Cheung ◽  
Maya M Erler ◽  
Un Jung Kang ◽  
Dalibor Sames ◽  
...  
Keyword(s):  
Globus Pallidus ◽  
Hot Spots ◽  
High Frequency ◽  
Dopamine Release ◽  
Electrochemical Analysis ◽  
Ph Sensitive ◽  
High Frequency Stimulation ◽  
Extracellular Milieu ◽  
Frequency Stimulation ◽  
Low Levels

Dopamine neurotransmission is suspected to play important physiological roles in multiple sparsely innervated brain nuclei, but there has not been a means to measure synaptic dopamine release in such regions. The globus pallidus externa (GPe) is a major locus in the basal ganglia that displays a sparse innervation of en passant dopamine axonal fibers. Due to the low levels of innervation that preclude electrochemical analysis, it is unknown if these axons engage in neurotransmission. To address this, we introduce an optical approach using a pH-sensitive fluorescent false neurotransmitter, FFN102, that exhibits increased fluorescence upon exocytosis from the acidic synaptic vesicle to the neutral extracellular milieu. In marked contrast to the striatum, FFN102 transients in the mouse GPe were spatially heterogeneous and smaller than in striatum with the exception of sparse hot spots. GPe transients were also significantly enhanced by high frequency stimulation. Our results support hot spots of dopamine release from substantia nigra axons.

Contralateral conjugate eye deviation during deep brain stimulation of the subthalamic nucleus

2007 ◽  
Vol 107 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Donald C. Shields ◽  
Alessandra Gorgulho ◽  
Eric Behnke ◽  
Dennis Malkasian ◽  
Antonio A. F. Desalles
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Internal Capsule ◽  
High Frequency Stimulation ◽  
Frontal Eye Field ◽  
Current Spread ◽  
Frequency Stimulation ◽  
Contralateral Eye ◽  
Deep Brain ◽  
Stimulation Of

Object Deep brain stimulation of the subthalamic nucleus (STN) in patients with Parkinson disease is often very effective for treatment of debilitating motor symptoms. Nevertheless, the small size of the STN and its proximity to axonal projections results in multiple side effects during high-frequency stimulation. Contralateral eye deviation is produced in a small percentage of patients, but the precise mechanism of this side effect is at present poorly understood. Methods Contralateral eye deviation was produced by high-frequency stimulation of 22 contact sites in nine patients undergoing deep brain stimulation of the STN. The precise locations of these contacts were calculated and compiled in order to locate the stimulated structure responsible for eye deviation. Results The mean x, y, and z coordinates associated with contralateral eye deviation were found to be 11.57, 2.03, and 3.83 mm lateral, posterior, and inferior to the anterior commissure–posterior commissure midpoint, respectively. The point described by these coordinates is located within the lateral anterosuperior border of the STN. Conclusions Given that stimulation of frontal eye field cortical regions produces similar contralateral conjugate eye deviation, these results are best explained by electrical current spread to nearby frontal eye field axons coursing lateral to the STN within the internal capsule. Thus, placement of the implanted electrode in a more medial, posterior, and inferior position may bring resolution of these symptoms by reducing the amount of current spread to internal capsule axons.

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