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PubMed2002

Movement-related modulation of neural activity in human basal ganglia and its L-DOPA dependency: recordings from deep brain stimulation electrodes in patients with Parkinson's disease.

Through electrodes implanted for deep brain stimulation in three patients (5 sides) with Parkinson's disease, we recorded the electrical activity from the human basal ganglia before, during and after voluntary contralateral finger movements, before and after L-DOPA. We analysed the movement-related spectral changes in the electroencephalographic signal from the subthalamic nucleus (STN) and from the internal globus pallidus (GPi). Before, during and after voluntary movements, signals arising from the human basal ganglia contained two main frequencies: a high beta (around 26 Hz), and a low beta (around 18 Hz). The high beta (around 26 Hz) power decreased in the STN and GPi, whereas the low beta (around 18 Hz) power decrease was consistently found only in the GPi. Both frequencies changed their power with a specific temporal modulation related to the different movement phases. L-DOPA specifically and selectively influenced the spectral power changes in these two signal bands.

Antiparkinson Agents↗
PubMed2004

Athymhormia and disorders of motivation in Basal Ganglia disease.

The author proposes a general model of human motivation as a separate function at the interface between emotion and action, which can be ascribed to subcortical circuits that are mainly centered on a subset of the basal ganglia and on their limbic connections. It is argued that the long-standing historical understatement of the notion of motivation in neurology is not only due to the complexity of the issue, which has proven hard to disentangle from other domains of dysfunction, but also to the persistence of some misleading conceptual orientations in the way neurologists have considered the brain mechanisms of goal-directed action, torn between a nonspecific "activation" view and an exclusively cognitive conception of motivation. How combining early clinical intuitions of some psychiatrists, careful clinical observations of neurological patients, and data derived from experimental studies in animals provide the basis for a coherent model of human motivation and its specific impairment in clinical neurology is explained. Clinical implications that can be drawn from such a model for some neuropsychiatric conditions are proposed.

Aged↗
PubMed2005

Neurotransplantation of fetal porcine cells in patients with basal ganglia infarcts: a preliminary safety and feasibility study.

BACKGROUND: Cell transplantation is safe in animal models and enhances recovery from stroke in rats. METHODS: We studied the safety and feasibility of fetal porcine transplantation in 5 patients with basal ganglia infarcts and stable neurological deficits. To prevent rejection, cells were pretreated with an anti-MHC1 antibody and no immunosuppressive drugs were given to the patients. RESULTS: The first 3 patients had no adverse cell, procedure, or imaging-defined effects. The fourth patient had temporary worsening of motor deficits 3 weeks after transplantation, and the fifth patient developed seizures 1 week after transplantation. MRI in both patients demonstrated areas of enhancement remote from the transplant site, which resolved on subsequent imaging. Two patients showed improvement in speech, language, and/or motor impairments over several months and persisted at 4 years. The study was terminated by the FDA after the inclusion of 5 patients. CONCLUSION: This is the first report on the transplantation of nontumor cells in ischemic stroke patients.

Adult↗
PubMed1989

Morphine-induced alterations of local cerebral glucose utilization in the basal ganglia of rats.

The actions of various doses of morphine on the local cerebral glucose utilization (LCGU) were studied by means of the autoradiographic [14C]2-deoxyglucose technique. Morphine (1-15 mg/kg i.p.) decreased LCGU in most areas of the basal ganglia (caudate nucleus, globus pallidus, nucleus accumbens), but not in the substantia nigra pars compacta. LCGU was also decreased in limbic nuclei, such as septum, hippocampus and amygdala, and in most thalamic areas. In most cortical regions, a decrease was found as well. Findings in some efferent nuclei seemed of particular interest, namely in the substantia nigra pars reticulata, anteroventral and lateral nucleus of the thalamus and the subthalamic nucleus, where decreases in LCGU were found after administration of 7.5 mg/kg or sometimes lower doses, but not after 15 mg/kg of morphine. The decreases seem to reflect a general depressory effect of morphine on neuronal activity which is known from electrophysiological studies. Part of these effects might be, in addition, due to an activation of dopaminergic neurons, since dopamine mainly acts as an inhibitory neurotransmitter. This dopaminergic activation leads to characteristic behavioral effects after lower doses of morphine. The largest dose used (15 mg/kg) produces muscular rigidity, probably by a direct action on the striatum. This effect antagonizes and masks the dopaminomimetic effects. The results suggest that it also antagonizes the functional alterations in some efferent nuclei of the basal ganglia manifest after lower doses of morphine. Local injections of morphine (15 micrograms) led to decreases of LCGU in the various parts of the striatum, but to increases in lateral and anteroventral thalamus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2000

Relationship between cerebral perfusion in frontal-limbic-basal ganglia circuits and neuropsychologic impairment in patients with subclinical hepatic encephalopathy.

UNLABELLED: Early detection of neuropsychologic impairment in cirrhotic patients with subclinical hepatic encephalopathy (SHE) is important for their prognosis and quality of life. Abnormal MRI and MR spectroscopy (MRS) findings have been proposed as early markers of brain damage in these patients, but the role of functional neuroimaging in this field still has to be defined. In this study, the SPECT perfusion pattern in patients with SHE was investigated, and the relationship between regional cerebral blood flow (rCBF) and the MRI, MRS, neuropsychologic evaluation and biochemical data of these patients was assessed. METHODS: Data were obtained from 13 cirrhotic patients with SHE and 13 age-matched healthy volunteers. Fasting venous blood ammonia and manganese sampling and a battery of standardized neuropsychologic tests related to basal ganglia function and sensitive to the effects of liver disease were all performed on the same day. MRI and 99mTc-hexamethyl propyleneamine oxime SPECT were performed within 2 wk. RESULTS: A pattern of decreased prefrontal rCBF was found in patients with SHE compared with healthy volunteers. Basal ganglia and mesial temporal rCBF correlated inversely with performance on motor tasks involving speed (Purdue pegboard test) and frontal premotor function (Luria graphic alternances and Stroop tests). Thalamic rCBF correlated positively with T1-weighted MRI signal hyperintensity in the globus pallidus and with abnormal MRS findings. Neither the MRI signal intensity of the globus pallidus nor MRS correlated with neuropsychologic test results. CONCLUSION: Cirrhotic patients with SHE show a SPECT pattern of impaired prefrontal perfusion that does not seem to account for their neuropsychologic deficits. On the other hand, perfusion in some parts of the limbic system and limbic-connected brain regions, such as the striatum and the mesial temporal regions, increased with neuropsychologic impairment. These findings suggest that brain SPECT may be more sensitive than MRI in delineating cirrhotic patients requiring in-depth clinical testing to reveal basal ganglia-related neuropsychologic alterations.

Basal Ganglia↗
PubMed1999

Increased basal ganglia iron levels in Huntington disease.

OBJECTIVE: To quantify in vivo brain ferritin iron levels in patients with Huntington disease (HD) and normal control subjects. DESIGN AND SUBJECTS: A magnetic resonance imaging method that can quantify ferritin iron levels with specificity in vivo was employed to study 11 patients with HD and a matched group of 27 normal controls. Three basal ganglia structures (caudate, putamen, and globus pallidus) and 1 comparison region (frontal lobe white matter) were evaluated. RESULTS: Basal ganglia iron levels were significantly increased (P<.002) in patients with HD, and this increase occurred early in the disease process. This was not a generalized phenomenon, as white matter iron levels were lower in patients with HD. CONCLUSIONS: The data suggest that increased iron levels may be related to the pattern of neurotoxicity observed in HD. Reducing the oxidative stress associated with increased iron levels may offer novel ways to delay the rate of progression and possibly defer the onset of HD.

Adult↗
PubMed1995

Distribution of limbic system-associated membrane protein immunoreactivity in primate basal ganglia.

The limbic system-associated membrane protein is a 64,000-68,000 mol.wt molecule known to be preferentially expressed by neurons in limbic structures of rats and cats. The present immunohistochemical study describes the distribution of this protein in the basal ganglia of Macaca fascicularis. The ventral striatum of the cynomolgus monkey displays a very intense immunostaining, whereas the dorsal striatum is much more weakly stained, except for some small zones scattered in the caudate nucleus and, to a lesser extent, in the putamen. These protein-rich zones are in register with striosomes, as visualized on adjacent sections immunostained for calbindin. At pallidal levels, immunostaining for the protein is observed only in the subcommissural regions, at the ventromedial tip of the internal pallidum, and in the caudoventral portion of the external pallidum. At nigral levels, the immunostaining is highly heterogeneous with a marked decreasing rostrocaudal gradient. The staining is most intense in nigral regions that receive striatal inputs and are enriched with calbindin. Nigral sectors populated by dopaminergic neurons, as visualized on adjacent sections immunostained for tyrosine hydroxylase, are largely devoid of immunoreactivity. In contrast, the immunostaining is uniformly intense in the ventral tegmental area. This study provides the first neuroanatomical evidence for teh existence of the limbic system-associated membrane protein in primate brain. It reveals that this glycoprotein is distributed in a highly heterogeneous manner in primate basal ganglia, where it preferentially labels regions that are anatomically and functionally linked to the limbic system.

Animals↗
PubMedDate not supplied

Distribution of iron in the basal ganglia and neocortex in postmortem tissue in Parkinson's disease and Alzheimer's disease.

Post-mortem tissue was obtained from subjects with Parkinson's disease (PD), Alzheimer's disease (AD) and age-matched controls. Iron levels were measured from various sites of the basal ganglia and neocortex using atomic absorption spectrophotometry. The results indicate that iron levels are increased in the substantia nigra and the lateral segment of the globus pallidus of parkinsonian tissue. In contrast, the medial segment of the globus pallidus shows reduced iron levels in AD when compared to age-matched controls. No significant alterations of iron concentration were detected in AD in any region. These results are discussed in terms of the role of iron in the basal ganglia, mechanisms of abnormal deposition and possible neurotoxicity in PD.

Aged↗
PubMed2003

Activation of basal ganglia loops in idiopathic Parkinson's disease: a PET study.

Patients with idiopathic Parkinson's syndrome (IPS) show dysexecutive deficits which are not related to dementia. We investigated whether these deficits may be caused by a disturbed interaction of prefrontal cortex and selective basal ganglia loops. 5 healthy right-handed volunteers and 5 non demented IPS patients were studied with FDG PET while performing a gambling task paradigm. Control subjects and patients showed consistent bilateral activation of the dorsolateral prefrontal cortex (DLPFC) and the left caudate. Only controls activated the right cingulate, mesial prefrontal and frontoorbital cortex. Patients significantly deactivated the right thalamus. Thus missing frontoorbital and frontomesial activity may indicate an impairment of the basal ganglia loop in IPS, connecting those regions to the thalamus via the ventral striate. The connections between DLPFC and Thalamus via the left caudate remained intact. This impairment may be the neuroanatomical correlate for dysexecutive syndromes in IPS more related to misjudgement than cognitive impairment.

Adult↗
PubMed1999

Compounds containing cytosolic choline in the basal ganglia: a potential biological marker of true drug response to fluoxetine.

OBJECTIVE: Studies have identified two types of antidepressant response: true drug response and placebo pattern response. This study examined the relationship between true drug response and choline-creatine ratios in the basal ganglia of depressed patients treated with fluoxetine. METHOD: The authors evaluated drug-free outpatients with major depression before (N = 41) and after (N = 15) 8 weeks of fluoxetine treatment, 20 mg/day, by using proton magnetic resonance spectroscopy. RESULTS: There was a significant difference in the degree of change from baseline to week 8 in choline-creatine ratios between the true drug response group (N = 8) and the placebo pattern response/nonresponse group (N = 7); the true drug response patients had a 20% increase in choline-creatine ratios, and the placebo pattern response/nonresponse patients had a 12% decrease in choline-creatine ratios. CONCLUSIONS: These data suggest that true drug response to fluoxetine treatment in depression may be associated with an increase in choline-creatine ratios in the basal ganglia.

Adult↗
PubMed2000

Anatomy of the dopamine system in the basal ganglia.

The dopaminergic nigropallidal and nigrosubthalamic projections control the activity of the globus pallidus and subthalamic nucleus neurons in both normal and pathological conditions. Intrastriatal dopaminergic neurons increase substantially in animal models of Parkinson's disease. They contain GABA, display the ultrastructural features of interneurons and form axo-axonic synapses with putative cortical-like glutamatergic boutons. The local dendritic release of dopamine by neurons in the substantia nigra pars compacta and ventral tegmental also influences basal ganglia functions. Thus, the long-term belief that the effects of dopamine in the basal ganglia were solely mediated through the nigrostriatal system must be changed to take into account extrastriatal dopaminergic projections and intrastriatal dopaminergic neurons.

Animals↗
PubMed1999

Basal ganglia involvement in rotational seizures.

Body rotation during partial epileptic seizures remains a poorly understood clinical feature, possibly related to the ictal involvement of specific cortical areas (e.g. vestibular cortex). However, there are both experimental and clinical arguments which support the hypothesis of basal ganglia asymmetric activation during such complex motor behavior. We report a patient exhibiting rotational seizures which proved to arise from right anterior temporal lobe structures and the orbito-cingular cortex, as demonstrated during stereotactic EEG recordings. An ictal 99mTc-ECD-SPECT study was performed during an electrically induced seizure, similar to the seizures usually experienced by the patient but without a rotatory component, showing a marked increase of cerebral blood flow in the lenticular nucleus, ipsilaterally to the epileptogenic area. This finding suggests that lenticulate involvement might be necessary to produce an ictal circling behavior. As circling behavior can be observed during epileptic seizures originating from areas widely distributed in the cortex, one may postulate that the basal ganglia involvement is the "final common pathway" underlying the rotational part of the clinical symptomatology.

Basal Ganglia↗
PubMed2003

Why the P600 is not just a P300: the role of the basal ganglia.

One of the important issues in event-related brain potential research is whether the language-related P600 and the P300 oddball effect are distinct components or not. We addressed this question by testing 14 aphasic patients, half of them with lesions including the basal ganglia and half of them with temporo-parietal lesions, in both an auditory oddball task and an experiment with auditory presented verb inflection violations. Whereas both patient groups displayed a clear P300 effect in the oddball experiment, only the group with temporo-parietal lesions showed a P600 in the language experiment. These data indicate that the basal ganglia seem to play a crucial role in the modulation of the P600, but not of the P300 component.

Aphasia↗
PubMed1994

CT findings of hypoxic basal ganglia damage.

The outcome of hypoxic ischemic injury ranges from complete recovery to a persistent vegetative state or death, depending on the length of time the patient remains unconscious and the degree of associated cardiac failure. We describe three patients who were comatose from a hypoxic and/or ischemic injury and whose principal computed tomographic (CT) finding was bilateral basal ganglia hypodensities. Two of these patients were discharged from the hospital with minimal residual neurologic deficits. These cases and review of the literature suggest that ischemic basal ganglia signs on CT scan are not necessarily a predictor of severe neurologic sequelae.

Adult↗
PubMed2001

Parallel cortico-basal ganglia mechanisms for acquisition and execution of visuomotor sequences - a computational approach.

Experimental studies have suggested that many brain areas, including the basal ganglia (BG), contribute to procedural learning. Focusing on the basal ganglia-thalamocortical (BG-TC) system, we propose a computational model to explain how different brain areas work together in procedural learning. The BG-TC system is composed of multiple separate loop circuits. According to our model, two separate BG-TC loops learn a visuomotor sequence concurrently but using different coordinates, one visual, and the other motor. The visual loop includes the dorsolateral prefrontal (DLPF) cortex and the anterior part of the BG, while the motor loop includes the supplementary motor area (SMA) and the posterior BG. The concurrent learning in these loops is based on reinforcement signals carried by dopaminergic (DA) neurons that project divergently to the anterior ("visual") and posterior ("motor") parts of the striatum. It is expected, however, that the visual loop learns a sequence faster than the motor loop due to their different coordinates. The difference in learning speed may lead to inconsistent outputs from the visual and motor loops, and this problem is solved by a mechanism called a "coordinator," which adjusts the contribution of the visual and motor loops to a final motor output. The coordinator is assumed to be in the presupplementary motor area (pre-SMA). We hypothesize that the visual and motor loops, with the help of the coordinator, achieve both the quick acquisition of novel sequences and the robust execution of well-learned sequences. A computational model based on the hypothesis is examined in a series of computer simulations, referring to the results of the 2 x 5 task experiments that have been used on both monkeys and humans. We found that the dual mechanism with the coordinator was superior to the single (visual or motor) mechanism. The model replicated the following essential features of the experimental results: (1) the time course of learning, (2) the effect of opposite hand use, (3) the effect of sequence reversal, and (4) the effects of localized brain inactivations. Our model may account for a common feature of procedural learning: A spatial sequence of discrete actions (subserved by the visual loop) is gradually replaced by a robust motor skill (subserved by the motor loop).

Basal Ganglia↗
PubMed1999

Extrastriatal dopaminergic innervation of human basal ganglia.

A tyrosine-hydroxylase immunohistochemical analysis of the brains of normal human individuals has revealed nigrostriatal axons providing collaterals that arborize in the pallidum and subthalamic nucleus. These thin and varicose collaterals emerge from thick and smooth axons that course backward along the main output pathways of the basal ganglia, including the ansa lenticularis, the lenticular fasciculus and Wilson's pencils. Many of these fibers run within pallidal medullary laminae before reaching the putamen, whereas others climb along the reticular thalamic nucleus to reach the caudate nucleus. This extrastriatal innervation, which allows nigral dopaminergic neurons to directly affect the pallidum and subthalamic nucleus, may play a crucial role in the functional organization of human basal ganglia, in both health and disease.

Adult↗
PubMed2000

Synaptic integration mediated by striatal cholinergic interneurons in basal ganglia function.

The physiological role of striatal cholinergic interneurons was investigated with immunotoxin-mediated cell targeting (IMCT). Unilateral cholinergic cell ablation caused an acute abnormal turning behavior. These mice showed gradual recovery but displayed abnormal turning by both excess stimulation and inhibition of dopamine actions. In the acute phase, basal ganglia function was shifted to a hyperactive state by stimulation and suppression of striatonigral and striatopallidal neurons, respectively. D1 and D2 dopamine receptors were then down-regulated, relieving dopamine-predominant synaptic perturbation but leaving a defect in controlling dopamine responses. The acetylcholine-dopamine interaction is concertedly and adaptively regulated for basal ganglia synaptic integration.

Acetylcholine↗