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PubMed2001

Pharmacological MRI mapping of age-associated changes in basal ganglia circuitry of awake rhesus monkeys.

While the pathophysiological changes induced by the loss of dopamine innervation in the basal ganglia by Parkinson's disease (PD) are well studied, little is known about functional changes in the neural circuitry of this area during normal aging. Here we report the first survey of age-associated changes in the basal ganglia of behaviorally characterized, awake rhesus monkeys, using pharmacological MRI to map responses to dopaminergic stimulation. Apomorphine, a mixed D(1)/D(2) dopamine receptor agonist, evoked little change in the substantia nigra (SN) of aged animals while significantly reducing activation in young adult monkeys. Compared to young animals, both apomorphine and d-amphetamine (which increases synaptic dopamine levels) significantly increased activation of the aged rhesus globus pallidus externa (GPe). In addition, the aged animals showed decreased activity in the putamen in response to d-amphetamine administration. Although the responses in the SN and putamen of the aged monkeys differed from those in animal models of PD, the apomorphine-evoked activation of their GPe corresponded with apomorphine-induced increases in neuronal activity seen in Parkinson's patients and animal models. Given the major role of the GPe in regulating motor behavior, the altered responses in the aged GPe may contribute significantly to the motor slowing and movement dysfunctions characterizing advanced age.

Aging↗
PubMed1995

[Obsessive-compulsive disorder and the basal ganglia].

Obsessive-compulsive disorder (OCD), characterized by obsessions and compulsions, was described as more frequent in patients with primary lesions of the basal ganglia suggesting that these brain structures may be also altered in OCD. The basal ganglia, that were considered important only for the motor control, are known now as crucial for many other mental functions as processing of cognitive experience. Recent studies using magnetic resonance image have found a tendency for smaller caudate nucleus in patients with OCD. Consistently, studies using functional neuroimaging suggest implication of a neurocircuit that includes the orbitalfrontal cortex, the cingulate cortex, caudate nucleus and thalamus in the pathophysiology of OCD. Among several hypotheses formulated to explain these findings, some authors speculated that a deficit of the caudate nucleus function would lead to inadequate filtering of worry inputs which would trigger the orbitalfrontal cortex to develop adaptative responses: the compulsions.

Basal Ganglia↗
PubMedDate not supplied

Extrapontine myelinolysis of the basal ganglia without central pontine myelinolysis.

Since the first descriptions of central pontine myelinolysis (CPM) were put forth it has become evident that myelinolysis may not be exclusively restricted to the pons. In many cases myelinolysis may share other brain regions, while in still others the pons may not be affected at all, as in the present case of pure basal ganglia myelinolysis. Regardless of geographic location, too rapid correction of hyponatremia has been invoked as the triggering mechanism which leads to both CPM and extrapontine myelinolysis (EPM). This case of EPM is that of a 61-year-old male who suffered spinal cord compression and quadriplegia due to the breakdown of a double cervical fusion at C4-5/C5-6 for herniated discs. One month later, following vomiting and poor food intake, a low serum Na+ of 101 mmol/l developed and was corrected to 128 mmol/l in 37 h (and from 104 mmol/l to 121 mmol/l in 15 h). Altered mental status ensued and a T2 weighted MRI showed symmetrical, bilateral high intensity foci in the basal ganglia 3 weeks before death. Histologically there were bilateral, circumscribed, spheroidal areas of demyelination involving the striatal fibers which course through the putamina. The pons was spared. This case illustrates that extrapontine, basal ganglia myelinolysis may occur in the absence of CPM or alternate areas of myelinolysis. We discuss other cases of EPM, with and without CPM, to define the brain regions involved. MRI is uncovering many new cases of EPM and CPM. This permits one to follow the evolution of the myelinolytic lesions and to correlate their progression or regression with treatment modalities and the neurological findings.

Basal Ganglia Diseases↗
PubMed2000

Mapping the basal ganglia: fMRI evidence for somatotopic representation of face, hand, and foot.

OBJECTIVE: To noninvasively investigate the somatotopy of the basal ganglia in humans. METHODS: Functional MRI, 1.5-T, was performed on six normal right-handed volunteers during simple acoustically paced motor tasks involving the right hand, foot, and face. RESULTS: In a single-subject analysis, statistical parametric maps showed overlapping activation extending along the anteroposterior extent of the left lentiform nucleus (LLN) for the hand, foot, and face representations. Within the LLN, the centers of gravity of each body part, reflecting both the extent and gradient of activation, were all located in the retrocommissural portion of the putamen. Their spatial relationship followed a similar pattern across subjects-face was medial to toes and fingers, toes were dorsal and rostral to fingers. CONCLUSIONS: The somatotopic organization of hand, face, and foot representation in the human lentiform nucleus suggests a triangular pattern, rather than the linear pattern seen in primate studies. The overlap observed between the distinct body parts differs from the cortical sensorimotor representation, indicating a different organizational concept of the basal ganglia.

Adult↗
PubMed2003

Basal ganglia network mediates the control of movement amplitude.

In the present study we address the hypothesis that the basal ganglia are specifically involved in the planning of movement amplitude (or related covariates). This prediction has often been put forward based on the observation that Parkinson's disease (PD) patients exhibit hypokinesia. A close examination of the literature shows, however, that this commonly reported clinical symptom is not consistently echoed by experimental observations. When required to point to visual targets in the absence of vision of the moving limb, PD subjects exhibit various patterns of inaccuracy, including hypometria, hypermetria, systematic direction bias, or direction-dependent errors. They have even been shown to be as accurate as healthy, age-matched subjects. The main aim of the current study is to address the origin of these inconsistencies. To this end, we required nine patients presenting with advanced PD and 15 age-matched control subjects to perform planar reaching movements to visual targets. Eight targets were presented in equally spaced directions around a circle centered on the hand's starting location. Based on a previously validated parsing procedure, end-point errors were segmented into localization and planning errors. Localization errors refer to the existence of systematic biases in the estimation of the initial hand location. These biases can potentially transform a simple pattern of pure amplitude errors into a complex pattern involving both amplitude and direction errors. Results indicated that localization errors were different in the PD patients and the control subjects. This is not surprising knowing both that proprioception is altered in PD patients and that the ability to locate the hand at rest relies mainly on the proprioceptive sense, even when vision is available. Unlike normal subjects, localization errors in PD were idiosyncratic, lacking a consistent pattern across subjects. When the confounding effect of initial hand localization errors was canceled, we found that end-point errors were only due to the implementation of an underscaled movement gain (15%), without direction bias. Interestingly, the level of undershoot was found to increase with the severity of the disease (inferred from the Unified Parkinson's Disease Rating Scale, UPDRS, motor score). We also observed that movement variability was amplified (32%), but only along the main movement axis (extent variability). Direction variability was not significantly different in the patient population and the control group. When considered together, these results support the idea that the basal ganglia are specifically involved in the control of movement amplitude (or of some covariates). We propose that this structure participates in extent planning by modulating cortical activity and/or the tuning of the spinal interneuronal circuits.

Aged↗
PubMed2004

Neuropsychological correlates of basal ganglia and medial temporal lobe NAA/Cho reductions in traumatic brain injury.

BACKGROUND: Proton magnetic resonance spectroscopy can assess neurochemical sequelae in traumatic brain injury. Metabolic abnormalities are present in the acute or subacute period in patients with traumatic brain injury and correlate with outcome on clinical scales. OBJECTIVE: To investigate the use of proton magnetic resonance spectroscopy in detecting possible gray subcortical neurochemical impairments and their relationship with neuropsychological performance. DESIGN: Group comparisons and correlations of brain metabolites with clinical and neuropsychological variables. PATIENTS AND METHODS: Metabolite concentrations were acquired from voxels localized to the basal ganglia and medial temporal region in 20 patients with long-term moderate and severe traumatic brain injury and 20 matched control subjects. Both groups underwent neuropsychological assessment. RESULTS: N-acetylaspartate-choline-containing compounds ratios were decreased in patients in the basal ganglia (t = -3.28, P =.002) and medial temporal region (t = -3.52, P =.001). The basal ganglia ratio correlated to measures of speed, motor scanning, and attention. CONCLUSION: Patients with long-term TBI present a regional correlation pattern that may help identify the neurological basis of cognitive sequelae in traumatic brain injury.

Adolescent↗
PubMed1986

Relations between basal ganglia and hippocampus: action of substantia nigra and pallidum.

Several interrelationships exist between basal ganglia and hippocampus. The ventral striatum appears to be involved in the control of the dopaminergic nigro-striatal pathway. The caudate, in turn, seems to influence the hippocampal theta rhythm and to inhibit hippocampal spikes. In the present work the role played by globus pallidus pars interna and substantia nigra pars compacta on hippocampal bioelectrical activity is studied. Injection of sodium penicillin i.v. produces steady interictal spikes in the hippocampus. Substantia nigra stimulation induces regular theta rhythm and inhibits the spikes. Pallidal stimulation, on the contrary, appears to strongly enhance epileptiform activity, proceeding to generalised seizure activity. The results are discussed in the light of a putative feedback loop from basal ganglia to hippocampus, probably underlying co-participation of the two subcortical structures in the control of motor behaviour.

Animals↗
PubMed1994

Germinoma originating in the basal ganglia and thalamus: MR and CT evaluation.

PURPOSE: To describe MR and CT features of germinoma originating in the basal ganglia and thalamus and to discuss the roles of each modality for its diagnosis. METHODS: MR and CT studies of six cases of germinomas, five of which were histologically proved, were retrospectively reviewed. T1-weighted, T2-weighted, and contrast-enhanced T1-weighted conventional spin-echo images, and unenhanced and contrast-enhanced CT images were evaluated. RESULTS: Typically, the tumor consisted of an irregular solid area with contrast enhancement and various-size cysts. Cystic components were found in five cases and calcification in four. Intratumoral hemorrhage was noted in one. Ipsilateral cerebral hemiatrophy and brain stem hemiatrophy were noted in three cases each. MR was superior to CT in evaluating precise tumor extension, cystic components, and intratumoral hemorrhage, although in one case, extension of the tumor was better defined on CT in its early stage. Calcification was difficult to identify by MR alone. The solid components of the tumors generally showed slightly high density on CT, which seemed to be characteristic compared with nonspecific intensity pattern on MR. CONCLUSION: The combination of CT and MR findings allows early detection and appropriate diagnosis of the mass in the basal ganglia and/or thalamus.

Adolescent↗
PubMed1992

Movement disorders in astrocytomas of the basal ganglia and the thalamus.

In a series of 225 patients with astrocytomas (grades I-IV) of the basal ganglia and the thalamus, 20 had a movement disorder. In all patients the histological diagnosis was verified by stereotactic biopsy. Tremor was observed in twelve patients, dystonia in eight, chorea in three, and chorea/ballismus and myoclonus in one. The tumour involved the thalamus in 16 patients. Corticospinal tract dysfunction was evident in 70% of the patients with movement disorders and in 73% of those without. Demographic, clinical, histological and neuroradiological data of the patients with a movement disorder were compared with the data of patients without. CT data yielded no differences with respect to the involvement of anatomical structures. Movement disorders were significantly associated with low-grade astrocytomas.

Adolescent↗
PubMed2000

Evidence for altered basal ganglia and cortical functions in transient idiopathic dystonia.

Idiopathic dystonia with onset in the first year of life has been described as a transient movement disorder, in contrast to other forms of idiopathic dystonia We report on a girl who showed, from her 5th month, episodes of dystonic postures of her neck and arm, which lasted for seconds and occurred several times a day. Neurologic findings and the psychomotor development were and remained normal. Neurometabolic screening tests and cerebral magnetic resonance imaging showed normal results. Functional cerebral imaging showed decreased perfusion of the basal ganglia and the left temperomesial cortex using single photon emission computed tomography (SPECT with technetium 99m hexamethylpropyleneamine oxime [99mTc-HMPAO]) and decreased glucose metabolism in the basal ganglia and the cerebellum using positron emission tomography (PET with [18F]fluorodeoxyglucose [18FDG]). Follow-up revealed that the episodes disappeared at the age of 16 months. The findings of PET and SPECT give evidence of an alteration in basal ganglia function but also in functions of other central nervous system regions, which may, however, be temporary.

Basal Ganglia↗
PubMed1991

[Hemodynamics in the cerebral cortex and basal ganglia--observation on normal volunteers and patients with lacunes using PET].

We examined ten healthy volunteers using positron emission tomography (PET) in order to elucidate regional changes and correlations in the cerebral circulation and oxygen metabolism. We also studied eight lacunar stroke patients so as to disclose the influences of vascular risk factors and aging on the cerebral blood flow and metabolism. We can conclude from our result as follows: 1. Cerebral blood volume (CBV) was minimum in the basal ganglia and cerebral blood flow (CBF)/CBV ratio was higher than that of cerebral cortex in healthy volunteers; 2. CBF of gray matter in healthy volunteers correlated with CBV and cerebral metabolic rate of oxygen where oxygen extraction fraction inversely correlated with CBF, CBV, and CBF/CBV; and 3. the basal ganglia CBF/CBV ratio in lacunar stroke patients was lower than that of healthy volunteers. These findings suggested that the perfusion pressure in the basal ganglia was so high in the normal condition that the angionecrosis or occlusion in the perforating arteries would be induced, especially in the aged and hypertensive patients.

Adult↗
PubMed2006

Effect of high-dose methyl-prednisolone on brainstem encephalopathy and basal ganglia impairment complicating cat scratch disease.

Cat scratch disease (CSD) is a zoonotic illness caused by the Gram negative bacillus Bartonella henselae characterized by a small skin lesion at the site of a bite, lick or scratch by a cat, commonly followed by regional lymphadenopathy 1 or 2 weeks later. We report herein on severe neurological complications of CSD combining brainstem encephalopathy and basal ganglia impairment. This 12-year-old female acutely presented to a local hospital with profound coma and a prolonged tonic posturing of extremities. On the neurological examination she was deeply comatose with pin-point pupils and lack of vestibulo-ocular responses, suggestive of brainstem encephalopathy, along with marked rigid hypertonicity suggestive also of basal ganglia impairment. Initially suspecting Herpes simplex encephalitis or acute disseminated encephalomyelitis she was promptly started with high-dose methyl-prednisolone and acyclovir. Her parents apparently reported that she was scratched by a kitten some 4 weeks prior to her present admission and as such, suspecting CSD, she was begun with doxycycline and rifampicin. Her serology had proven positive for IgM antibodies to Bartonella henselae establishing the diagnosis. She regained consciousness after 4 days and the signs of brainstem and extra-pyramidal impairment also gradually abated and disappeared after 10 days. A follow-up exam after a month disclosed mild extra-pyramidal abnormalities which disappeared after 3 months. Although extremely rare, CSD should be also considered in a patient presenting with a severe encephalopathy and associated basal ganglia impairment. The prompt administration of high-dose methyl-prednisolone upon admission may have contributed to the favorable outcome in our patient and therefore should be advocated in any patient presenting with profound encephalopathy regardless the underlying etiology recovered later.

Basal Ganglia↗
PubMed2001

Basal ganglia dysfunction, working memory, and sentence comprehension in patients with Parkinson's disease.

To investigate the role of the basal ganglia in working memory and sentence comprehension, 14 patients with Parkinson's disease (PD) were administered experimental measures of semantic and phonological working memory, and a measure of sentence comprehension, while receiving dopaminergic medications and after a period of withdrawal from these medications. An age- and education- matched control group (N=14) received the same measures. Comparison with control subjects revealed deficits in patients with PD in sentence processing regardless of medication status, but no deficits in working memory. In contrast to previous studies, withdrawal of dopaminergic medications had no significant impact on task- related working memory functions or on sentence comprehension. Results suggest that basal ganglia dysfunction does not solely account for sentence comprehension deficits seen in PD.

Aged↗
PubMed1993

Basal ganglia germinoma with crossed cerebellar diaschisis--case report.

An 8-year-old boy presented with a germinoma of the right basal ganglia manifesting as gradual onset of mild left hemiparesis. Computed tomography (CT) and magnetic resonance imaging disclosed a mass lesion in the right basal ganglia with mild right cerebral hemiatrophy. Single photon emission CT revealed decreased cerebral blood flow in both the right cerebral and left cerebellar hemispheres, or crossed cerebellar diaschisis. The histology of a specimen from a stereotactic needle biopsy was compatible with two-cell pattern germinoma. After irradiation and chemotherapy, the mass lesion disappeared completely. The clinical symptoms and crossed cerebellar diaschisis gradually improved.

Basal Ganglia Diseases↗
PubMed2003

Normal prism adaptation but reduced after-effect in basal ganglia disorders using a throwing task.

Prism adaptation is a form of visuomotor learning in which the visual and motor systems need to be adjusted because a visual perturbation is produced by horizontally displacing prisms. Despite being known for over two centuries, the neuronal substrates of this phenomenon are not yet completely understood. In this article the possible role of the basal ganglia in this kind of learning was analysed through a study of Huntington's and Parkinson's disease patients. A throwing technique requiring the use of open loop feedback was used. The variables analysed were visuomotor performance, adaptation rate and magnitude, and the after-effect. The results clearly showed that both Huntington's and Parkinson's disease groups learned at the same rate as control subjects. In addition, despite having a disturbed visuomotor performance, both experimental groups showed the same adaptation magnitude as the control group. Finally, the after-effect, which is measured after removing the prisms, is reduced in both patients groups. This reduction leads to a disruption in the normal adaptation-after-effect correlation found in normal volunteers. These results suggest that basal ganglia are not involved in this type of open-looped visuomotor learning. The large number of patients studied as well as the similarity of the findings between both populations support this hypothesis. By contrast, there is an impairment in the after-effect on both basal ganglia patient populations. This impairment may be the result of the deterioration of the perceptual recalibration process involved in visuomotor learning.

Adaptation, Ocular↗