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PubMed2003

Temporal parenteral nutrition in children causing t1 shortening in the anterior pituitary gland and globus pallidus.

Patients receiving long-term parenteral nutrition (PN) with trace elements (TE) may exhibit T (1) shortening in the anterior pituitary gland and basal ganglia. The purposes of this study were to clarify at what time or from what site the signal change begins in children. Retrospective analysis of magnetic resonance imaging results was performed for 10 pediatric patients aged from 1 to 16 years receiving temporal PN, eight of which received PN with TE for less than two months, and 13 patients with headache or seizures as age-matched controls. Axial and sagittal T (1)-weighted images were obtained to analyze the T (1) shortening in the anterior pituitary gland and globus pallidus. All eight patients receiving PN with TE exhibited T (1) shortening in the anterior pituitary gland (six patients) and/or globus pallidus (five patients). No T (1) shortening was observed in the other two patients without TE, or the 13 age-matched controls. Therefore, the signal change may be associated with TE administration, and begins markedly earlier than previously reported. We discussed the possibility that manganese (Mn) caused the signal change, and proposed that the administration of a lower dose of Mn is recommended, even in the case of temporal PN, to prevent possible Mn toxicity toward both the brain and liver.

Adolescent↗
PubMed1985

Influence of the globus pallidus on arm movements in monkeys. III. Timing of movement-related information.

Monkeys were trained to make a visually triggered arm-reaching movement to a lighted button in a simple reaction-time paradigm, during which the reaction time (RT) and movement time (MT) were measured. Stimulus trains of varying duration were applied at various times before and during the movement at locations in the globus pallidus where application of long stimulus trains caused increased MTs. A critical stimulus period was identified during which stimulus application effectively prolonged MTs. The activity of pallidal neurons was examined during performance of the same behavioral task. More than 60% of the neurons examined showed task-related changes in activity that began before or during the reaching movement. For 45% of these cells, the initial change in firing occurred during the critical stimulus period, 50-150 ms before mechanically detected movement. Comparison of the critical stimulus period, the time of task-related changes in the discharge of pallidal neurons, and the time of EMG activity in muscles acting at the back, shoulder, elbow, and wrist revealed that both the critical stimulus period and changes in neuronal discharge occurred at or after initial muscle activation and during the buildup of EMG activity. These data are consistent with a model in which the globus pallidus plays a role in scaling the magnitude of muscle activity that determines movement velocity without affecting the initiation or sequential organization of the programmed motor output.

Animals↗
PubMed1986

Diurnal rhythm of the in vivo release of enkephalin from the globus pallidus of the rat.

The in vivo spontaneous release of enkephalin in the globus pallidus of the rat increases from noon to evening by 100%; during this period the local release of exogenous gamma-aminobutyric acid (GABA) decreases by 60%. These diurnal rhythms are more marked in the K+-stimulated release: enkephalin-induced output increases 6-fold while GABA decreases 10-fold during the afternoon and evening hours. Since pallidal enkephalin and GABA are involved in the control of locomotor activity we suggest that these rhythms may be linked to the circadian changes of activity in the rat.

Animals↗
PubMed1991

Cholinergic projections from the globus pallidus to the lateral amygdaloid nucleus in the cat.

Direct projections from the globus pallidus (GP) to the lateral amygdaloid nucleus (A1) were found in the cat by the anterograde and retrograde tracing methods. Pallido-amygdaloid fibers originated mainly from the caudal half of the GP and distributed throughout the entire extent of the A1; most densely in the lateral part of the A1. Choline acetyltransferase immunohistochemistry in combination with retrograde fluorescent tracing indicated that most pallido-amygdaloid neurons were cholinergic.

Amygdala↗
PubMed1982

Strain differences in recovery from sensorimotor neglect after unilateral globus pallidus lesions in mice.

Recovery of somatosensory orientation after unilateral electrolytic lesions of globus pallidus was studied in two inbred strains of mice (C57BL/6, Sec 1/ReJ). During the first four post-lesion days mice of both strains did not react to tactile stimuli (von Frey hair of 2 g intensity) applied to the thorax area contralateral to the lesion. Successively, there was a gradual replacement by non-oriented activation and incomplete oriented responses, followed by normal precise orientation. Recovery of orientation proceeded at a significantly higher rate in C57 mice. After a period of four months C57 mice reached a recovery level of 91% in comparison to 56% of Sec mice. The genotype dependent differences of recovery mechanisms are discussed in terms of plasticity and dopaminergic systems.

Animals↗
PubMed1990

Physiological properties of projection neurons in the monkey striatum to the globus pallidus.

In order to study neuronal information transfer from the striatum to the globus pallidus (GP) during voluntary movement, we recorded activity of electrophysiologically identified projection neurons in the putamen to the GP while the monkey was performing learned movement tasks. Two categories of putamen neurons were recorded: one with tonic spontaneous discharges at about 2-7 impulses/s responded to external sensory stimuli (type I); the other with very low spontaneous discharge rates less than 0.5 impulses/s showed phasic burst discharges which were time-locked to limb or orofacial movements (type II). All of the putamen neurons identified as projecting to the GP (external and/or internal segment) by an antidromic activation from electrical stimulation of the GP were type II cells. It was concluded that the movement-related activity of type II putamen neurons is transferred to GP and/or SN during voluntary movement but tonically active type I cells do not project to the GP.

Action Potentials↗
PubMed1988

Abnormal influences of passive limb movement on the activity of globus pallidus neurons in parkinsonian monkeys.

Extracellular single unit activity was recorded in the globus pallidus of waking Macaca fascicularis during passive limb movement. The main upper and lower limb joints were investigated bilaterally. The animals were either intact or rendered parkinsonian by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Cell counts showed that at least 90% of nigral neurons of the compacta-type were degenerated in the parkinsonian animals. In the intact animals, only 17% of the pallidal neurons responded to the natural stimulus. As already reported by others, the responses were typically related to movement about a single contralateral joint and in only one direction. In the parkinsonian animals, however, more neurons responded, often more vigorously, to the same stimulation. In many of these neurons the responses were elicited by movement about more than one joint of both upper and lower limbs or ipsi-and contralateral sides and in more than one direction. The increase in number and magnitude and loss of specificity of responses were much greater in the internal pallidal segment, where the number of responding neurons quadrupled. These results suggest that dopaminergic mechanisms regulate gain and selectivity in the basal ganglia. In animals with decreased dopaminergic functions, the excessive and unselective motor responses may explain all 3 major signs of parkinsonism: rigidity, tremor and akinesia.

Animals↗
PubMed2000

Measurement of tissue electrical impedance confirms stereotactically localized internal segment of the globus pallidus during surgery.

Lesions surgically made in the internal segment of the posteroventral globus pallidus (Gpi) reduce many medically intractable symptoms in patients with Parkinson's disease. The Gpi is localized for pallidotomy by stereotactic procedures. We sought to confirm the stereotactically localized Gpi segment by measuring impedance between the tip of an active electrode that was advanced toward the target and a remote reference electrode. A stereotactic instrument was used to place an active electrode in 53 conscious patients undergoing pallidotomy. The electrode was manually advanced slowly toward the Gpi segment by a microdrive. Impedance was measured every 10 mm initially and every 1 mm in the final 10 mm of the electrode's advancement, using an impedance monitor interconnected with a lesion generator. Measurements were continued for several millimeters after each patient's target was reached. Impedance values ranged from 250 to 350 ohms throughout of the electrode passage. Impedance increased by 25-35 ohms at 1-3 mm before the center of the target and then dropped abruptly when the electrode passed the target. Impedance values depended strongly on the electrode's configuration. The impedance measurement confirmed the location of each surgical target identified by stereotactic navigation. The accuracy of the impedance measurement is acceptable, and the procedure can be recommended as an aid to confirm the stereotactically localized Gpi during neurological surgery.

Adult↗
PubMed1998

Immediate motor effects of stimulation through electrodes implanted in the human globus pallidus.

The immediate motor effects of stimulation through electrodes chronically implanted in the globus pallidus internus (GPI) were studied in 9 subjects with Parkinson's disease. Single stimuli (at >>0.4 Hz) produced short latency facilitation of voluntarily activated contralateral muscles in all subjects. The latency and distribution of the facilitation, its probably monosynaptic nature, and the short chronaxie and refractory period of the activated neural elements suggest that the facilitation results from the direct excitation of the fast conducting corticospinal pathway. The facilitation of motoneurons followed high frequency (e.g. 200 Hz) stimulation without decrement and occurred at stimulus intensities well below those required to produce a visible muscle contraction. We conclude that, while there may be other effects, GPI stimulation through electrodes may activate the corticospinal tract, even when the stimuli are below the threshold for a visible muscle contraction, and that continuous stimulation may do so continuously. This may be an unwanted side effect, but possible therapeutic actions are considered. The reproducible short latency facilitation enabled us to estimate current spread from the quadripolar electrodes used for deep brain stimulation. When the current is sufficient to excite large myelinated fibers near one of the quadripolar electrodes, an additional 1-mA current will activate similar fibers at an additional distance of 1.8 mm with bipolar stimulation and at a distance of 5.7 mm with monopolar stimulation.

Chronaxy↗
PubMed2006

Globus pallidus stimulation in advanced Parkinson's disease.

Deep brain stimulation (DBS) of the globus pallidus internus (GPi) has become an accepted therapeutic modality in selected Parkinson's disease (PD) patients with severe levodopa-induced dyskinesias (LID) and on-off motor fluctuations. In comparison to subthalamic nucleus DBS there is a paucity of data on GPi DBS outcomes. We present our experience with a group of 20 PD patients (9 unilateral, 11 bilateral) who underwent GPi stimulation. PD motor symptoms were assessed using the Unified Parkinson's Disease Rating Scale (UPDRS) part III scores and subscores, and dyskinesia using the Abnormal Involuntary Movement Scale (AIMS), UPDRS part IVa, and clinical global impression (CGI). At mean follow-up time of 7 months, bilateral stimulation reduced off-period motor scores by a mean of 46% and on-period motor scores by 18%. Unilateral stimulation reduced off-period motor scores by 18%. Dyskinesia severity was reduced by 76%, which was maintained after a mean follow-up time of 35 months. Antiparkinsonian medication dosage was unchanged. No major adverse effects were seen. Unilateral and bilateral GPi DBS provides lasting benefit in PD patients with severe LID. Beneficial effects on off-period motor symptoms are greater with bilateral stimulation; however, with maintenance of dopaminergic medication, unilateral procedures can also provide important and sustained benefits.

Aged↗
PubMed2004

The mechanism and effect of chronic electrical stimulation of the globus pallidus for treatment of Parkinson disease.

OBJECT: Although chronic electrical stimulation of the globus pallidus (GP) has been shown to ameliorate motor disabilities in Parkinson disease (PD), the underlying mechanism remains to be clarified. In this study the authors explored the mechanism for the effects of deep brain stimulation of the GP by investigating the changes in neurotransmitter levels in the cerebrospinal fluid (CSF) during the stimulation. METHODS: Thirty patients received chronic electrical stimulation of the GP internus (GPi). Clinical effects were assessed using the Unified PD Rating Scale (UPDRS) and the Hoehn and Yahr Staging Scale at 1 week before surgery and at 6 and 12 months after surgery. One day after surgery, CSF samples were collected through a ventricular tube before and 1 hour after GPi stimulation. The concentration of neurotransmitters such as gamma-aminobutyric acid (GABA), noradrenaline, dopamine, and homovanillic acid (HVA) in the CSF was measured using high-performance liquid chromatography. The treatment was effective for tremors, rigidity, and drug-induced dyskinesia. The concentration of GABA in the CSF increased significantly during stimulation, although there were no significant changes in the level of noradrenaline, dopamine, and HVA. A comparison between an increased rate of GABA concentration and a lower UPDRS score 6 months postimplantation revealed that the increase in the GABA level correlated with the stimulation-induced clinical effects. CONCLUSIONS: Stimulation of the GPi substantially benefits patients with PD. The underlying mechanism of the treatment may involve activation of GABAergic afferents in the GP.

Adult↗
PubMed1992

Responses of globus pallidus neurons to cortical stimulation: intracellular study in the rat.

The responses of globus pallidus (GP) neurons to stimulation of the sensorimotor cortex, the neostriatum, and the subthalamic nucleus were intracellularly recorded in anesthetized rats. Stimulation of the cortex evoked a sequence of postsynaptic responses including an initial short EPSP, a short IPSP, and a late EPSP with multiple spikes in most of the repetitively firing GP neurons. The response pattern was very similar to those evoked by striatal stimulation, except that the latencies were longer. An acute knife cut placed immediately caudal to the substantia nigra caused no significant change in the responses to cortical and striatal stimulation. Stimulation of the subthalamic nucleus evoked a short latency EPSP overlapped with an IPSP. The polarity of all the IPSPs was reversed by a Cl- injection. A systemic injection of picrotoxin abolished all the IPSPs and unmasked large depolarizations with multiple spikes. An ibotenic acid lesion of the subthalamic nucleus eliminated both the initial short latency and late EPSPs to cortical and striatal stimulation and disclosed a prominent IPSP. Stimulation of the lesioned subthalamic nucleus also evoked large, short latency IPSPs without noticeable EPSPs. These results indicate that (i) the IPSPs evoked by cortical, striatal, and subthalamic stimulation were mediated by a GABAA receptor, (ii) both the initial and late EPSPs to cortical and striatal stimulation involved activation of the subthalamic nucleus but not brainstem nuclei, and (iii) cortically derived signals mediated through the neostriatum (i.e. long latency IPSPs) and the subthalamic nucleus (i.e. short latency EPSPs) converged on most GP neurons.

Animals↗
PubMed2004

Molecular, chemical, and anatomical characterization of globus pallidus dopamine D2 receptor mRNA-containing neurons.

Essential for normal movement, the globus pallidus (GP) is a prominent nucleus whose neurons project to all other basal ganglia nuclei. The GP is composed of at least two distinct neuron populations. GP neurons of the rodent contain either the calcium-binding protein parvalbumin (PV) or preproenkephalin (PPE) mRNA, differentially innervate several basal ganglia structures, and have distinct immediate early gene responses to dopamine agonists or antagonists. Recent research has revealed that dopamine directly influences GP neurons, with D2 receptors contributing to both pre- and postsynaptic effects of dopaminergic agents. The existence of D2 mRNA-expressing (D2+) GP neurons has been established, but little is known concerning their numbers, regional distribution, or relationship to pallidal subpopulations identified on the basis of PV immunocytochemistry, PPE mRNA, or axonal targets. Detection of pallidal D2 mRNA with a 35S-cRNA probe revealed that D2+ neurons are found throughout the GP, comprising approximately one-half of pallidal neurons, but they are most dense within a dorsoventral band in lateral GP. While a substantial proportion (42-51%) of all chemically and anatomically labeled pallidal neuron subpopulations expressed D2 transcript, the D2+ neurons exhibited both population-based and regional heterogeneities. Overall, the pallidostriatal cells had a greater density of D2 mRNA than did pallidosubthalamic cells. Also, compared to other pallidal regions, the ventromedial GP contained fewer D2+ cells, and the PPE mRNA-expressing cells in this region had lower densities of D2 mRNA per neuron. These results reveal heterogeneous chemical and anatomical properties of the extensive population of D2+ GP neurons, a potential cellular substrate for dopamine's effects in pallidum.

Animals↗
PubMed2002

Calbindin D-28k positive projection neurones and calretinin positive interneurones of the rat globus pallidus.

Immunohistochemistry for three calcium-binding proteins calbindin D-28k, calretinin, and parvalbumin revealed neuronal heterogeneity within the GP. Each neurone appeared to express either a single type of calcium binding protein or none at all. The co-localisation of calcium binding proteins was not observed. Combined immunohistochemistry and retrograde tract tracing using colloidal gold particles injected into the projection fields, the substantia nigra or subthalamic nucleus, revealed that projection neurones could be labelled with either calbindin or parvalbumin. These cells were of medium size (22 x 12 microm), multipolar and moderate varicose dendritic trees. In contrast, calretinin-positive neurones were never retrogradely labelled, even in regions where neuronal colloidal gold deposits were numerous. This, combined with their rarity (<1%) and small size (11 x 9 microm), suggests that calretinin may be a neurochemical marker for putative rat globus pallidus interneurones. Calcium-binding proteins are known to have unique buffering characteristics that may confer specific functional properties upon pallidal neurones. Indeed, differential calcium binding protein expression may underlie the electrophysiological heterogeneity observed in the rat globus pallidus.

Animals↗
PubMed1996

Efferent connections of the caudal part of the globus pallidus in the rat.

The efferent connections of the caudal pole of the globus pallidus (GP) were examined in the rat by employing the anterograde axonal transport of Phaseolus vulgaris leucoagglutinin (PHA-L), and the retrograde transport of fluorescent tracers combined with choline acetyltransferase (ChAT) or parvalbumin (PV) immunofluorescence histochemistry. Labeled fibers from the caudal GP distribute to the caudate-putamen, nucleus of the ansa lenticularis, reuniens, reticular thalamic nucleus (mainly its posterior extent), and along a thin strip of the zona incerta adjacent to the cerebral peduncle. The entopeduncular and subthalamic nuclei do not appear to receive input from the caudal GP. Descending fibers from the caudal GP course in the cerebral peduncle and project to posterior thalamic nuclei (the subparafascicular and suprageniculate nuclei, medial division of the medial geniculate nucleus, and posterior intralaminar nucleus/peripeduncular area) and to extensive brainstem territories, including the pars lateralis of the substantia nigra, lateral terminal nucleus of the accessory optic system, nucleus of the brachium of the inferior colliculus, nucleus sagulum, external cortical nucleus of the inferior colliculus, cuneiform nucleus, and periaqueductal gray. In cases with deposits of PHA-L in the ventral part of the caudal GP, labeled fibers in addition distribute to the lateral amygdaloid nucleus, amygdalostriatal transition area, cerebral cortex (mainly perirhinal, temporal, and somatosensory areas) and rostroventral part of the lateral hypothalamus. Following injections of fluorescent tracer centered in the lateral hypothalamus, posterior intralaminar nucleus, substantia nigra, pars lateralis, or lateral terminal nucleus, a substantial number of retrogradely labeled cells is observed in the caudal GP. None of these cells express ChAT immunoreactivity, but, except for the ones projecting to the lateral hypothalamus, a significant proportion is immunoreactive to PV. Our results indicate that caudal GP efferents differ from those of the rostral GP in that they project to extensive brainstem territories and appear to be less intimately related to intrinsic basal ganglia circuits. Moreover, our data suggest a possible participation of the caudal GP in feedback loops involving posterior cortical areas, posterior striatopallidal districts, and posterior thalamic nuclei. Taken as a whole, the projections of the caudal GP suggest a potential role of this pallidal district in visuomotor and auditory processes.

Amidines↗
PubMed2004

Neuronal activity in the globus pallidus of multiple system atrophy patients.

The pathophysiological changes in neural activity that characterize multiple system atrophy (MSA) are largely unknown. We recorded the activity of pallidal neurons in 3 patients with clinical and radiological features of MSA who underwent unilateral microelectrode-guided pallidotomy for disabling parkinsonism. Findings in these patients were compared with 4 control patients with a clinical diagnosis of Parkinson's disease (PD). The position, firing rates, and firing patterns of single neurons in the pallidal complex were analyzed in both MSA and PD patients. The mean spontaneous firing rate of neurons in the internal segment of the globus pallidus internus (GPii) was significantly lower in MSA than in PD patients. There were no significant differences between MSA and PD patients, however, in firing rates of neurons in the external globus pallidus (GPe) or in the external segment of GPi (GPie). In addition, no significant differences in firing pattern were found between MSA and PD patients. In conclusion, this study has shown that firing rates of neurons in GPii but not in GPie and GPe are different in MSA patients compared with that in PD patients, a finding that may reflect the poor clinical results of pallidotomy reported in patients with MSA.

Adult↗
PubMedDate not supplied

CCK-8S systemic administration blocks the 7-nitroindazole-induced effects on the EEG of striatum and globus pallidus: a FFT analysis in the rat.

BACKGROUND: Nitric oxide (NO) and cholecystokinin (CCK) are involved in the modulation of several neurotransmitter systems in the basal ganglia, and a functional interaction between their modulatory effects could be hypothesised. MATERIALS AND METHODS: We studied the effects exerted by the administration of 7-nitroindazole (7-NI) (50 mg kg(-1) i.p.), a selective inhibitor of neuronal NO synthase, on the depth EEG activity of the striatum and of the globus pallidus in both not pre-treated and sulphated CCK octapeptide (CCK-SS)-treated (100 nM kg(-1) i.p.) rats. Striatal and pallidal depth EEG power spectra were examined by means of a Fast Fourier Transform analysis. RESULTS: Striatal depth recordings showed a marked increase of % power of slow standard rhythms after 7-NI systemic treatment. In contrast, pallidal recordings revealed an increase of % power of rapid standard rhythms after i.p. injection of 7-NI. The same modifications were not evidenced in CCK-8S pre-treated rats after 7-NI administration. CONCLUSION: The results show an influence exerted by peripheral CCK on the nitrergic modulation of the bioelectric activities of the striatum and of the globus pallidus. This effect could be of particular interest in the light of NO and CCK involvement in the neuroprotective mechanisms.

Animals↗
PubMed1999

[Treatment of early-onset generalized dystonia by chronic bilateral stimulation of the internal globus pallidus. Apropos of a case].

Dystonia musculorum deformans is an inherited severe disease, with a wide clinical polymorphism. The most severe clinical forms with early onset carry a high risk of life-threatening complications. In the absence of any efficient medical treatment, bilateral pallidotomy has previously been reported to be of value in the management of this disease. We report the first clinical case of a severe early-onset generalized dystonia dramatically improved by a bilateral stimulation of the internal globus pallidus. In November 1996, we proposed this neurosurgical procedure for a 8-year-old girl, who had suffered since the age of 3 from severe generalized dystonia, and who progressively became totally dependent and bedridden. She had been under sedation and permanent controlled respiratory assistance for the last two months. The etiology of the disease remained unknown (the DYT1 mutation was absent). Under general anesthesia, we bilaterally implanted a four-contacts electrode in the internal globus pallidus, using the Leksell's stereotactic frame and a 1.5 tesla MRI control. A dramatic improvement was noted 6 weeks later and led us to connect the two electrodes to neurostimulators inserted under the abdominal skin.

Age of Onset↗