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PubMed1993

Pineal ganglioglioma in a patient with familial basal ganglia calcification and elevated serum alpha-fetoprotein: case report.

Pineal ganglioglioma was diagnosed in a 36-year-old man with familial basal ganglia calcification and elevated serum alpha-fetoprotein. The patient was treated surgically with a good result. Only four other cases of this tumor have been reported. His 38-year-old brother also showed basal ganglia calcification and elevated serum chorionic gonadotropin as well as alpha-fetoprotein. Familial basal ganglia calcification with elevated serum alpha-fetoprotein in a nonhepatic benign condition is rare. The pathogenesis of these conditions is discussed.

Adult↗

PubMed2004

Hippocampus, cortex, and basal ganglia: insights from computational models of complementary learning systems.

We present a framework for understanding how the hippocampus, neocortex, and basal ganglia work together to support cognitive and behavioral function in the mammalian brain. This framework is based on computational tradeoffs that arise in neural network models, where achieving one type of learning function requires very different parameters from those necessary to achieve another form of learning. For example, we dissociate the hippocampus from cortex with respect to general levels of activity, learning rate, and level of overlap between activation patterns. Similarly, the frontal cortex and associated basal ganglia system have important neural specializations not required of the posterior cortex system. Taken together, this overall cognitive architecture, which has been implemented in functioning computational models, provides a rich and often subtle means of explaining a wide range of behavioral and cognitive neuroscience data. Here, we summarize recent results in the domains of recognition memory, contextual fear conditioning, effects of basal ganglia lesions on stimulus-response and place learning, and flexible responding.

Animals↗

PubMed2000

Basal ganglia neurotoxins.

The epidemiology, clinical features, pathology, and mechanisms of action of basal ganglia neurotoxins are reviewed. Manganese, cyanide, hydrogen sulfide, methanol, carbon monoxide, 3-nitropropionic acid, MPTP, and annonaceae alkaloids are discussed. The probable mechanism of action for almost all basal ganglia neurotoxins is inhibition of mitochondrial function with destruction of the pallidum and putamen. MPTP produces selective loss of dopaminergic neurons because of selective uptake of a toxic metabolite in dopaminergic neurons. The basis for selective vulnerability of the putamen and pallidum is unknown.

Animals↗

PubMed1998

Crossed cerebellar diaschisis due to intracranial hematoma in basal ganglia or thalamus.

UNLABELLED: The purpose of our study was to evaluate the remote effects on the cerebellum and cerebral cortex from subcortical hematoma without cortical structural abnormality. METHODS: Our study included 23 patients with hematoma, strictly confined either to the basal ganglia (n = 12) or thalamus (n = 11) without cortical abnormality on CT or MRI. Twenty psychiatric patients without structural abnormality on MRI were selected as control subjects. Technetium-ethyl cysteinate dimer brain SPECT was performed in patients and control subjects. Regional cerebral blood flow (rCBF) was visually and semiquantitatively assessed. Asymmetry index (AI) was determined using data from regions of interest at the basal ganglia, thalamus, cerebellum, frontal, parietal and temporal cortex to support the semiquantitative analysis. The criteria for defining hypoperfusion that reflected diaschisis was based on an AI > the mean + 2 s.d. of AI in control subjects. RESULTS: In the basal ganglia hematoma, rCBF was reduced significantly in the contralateral cerebellum (10/12), ipsilateral thalamus (12/12), ipsilateral frontal (6/12), parietal (12/12) and temporal cortex (10/12). As for thalamic hematoma, significantly reduced perfusion was seen in the contralateral cerebellum (10/11), ipsilateral basal ganglia (7/11), ipsilateral frontal (5/11), parietal (11/ 11) and temporal cortex (3/11). CONCLUSION: Crossed cerebellar diaschisis (CCD) and cortical diaschisis frequently were observed in patients with subcortical hematoma without cortical structural abnormality. This suggested that CCD can develop regardless of interruption of the corticopontocerebellar tract, which is the principal pathway of CCD.

Adult↗

PubMed1999

Basal ganglia alterations and brain atrophy in Huntington's disease depicted by transcranial real time sonography.

OBJECTIVES AND METHODS: Transcranial real time sonography (TCS) was applied to 49 patients with Huntington's disease and 39 control subjects to visualise alterations in the echotexture of the basal ganglia. For comparison T1 weighted, T2 weighted, and fast spin echo MRI was performed in 12 patients with Huntington's disease with and in nine patients without alterations of the basal ganglia echotexture as detected by TCS and T1 weighted, T2 weighted, and fast spin echo MRI. Furthermore, the widths of the frontal horns, third ventricle, and the lateral ventricles were depicted in TCS examinations and correlations examined with corresponding CT slices. RESULTS: Eighteen out of 45 (40%) of the patients with Huntington's disease with adequate insonation conditions showed hyperechogenic lesions of at least one basal ganglia region. In 12 patients TCS depicted hyperechogenic lesions of the substantia nigra; in six patients the head of the caudate nucleus was affected. The lentiform nucleus (n=3) and the thalamus (n=0) were less often affected or spared. Hyperechogenic lesions were significantly more frequent in patients with Huntington's disease than in 39 control subjects, who had alterations of the echotexture in 12.8% (4/39) of the examinations. The number of CAG repeats and the clinical status correlated with the identification of hyperechogenic lesions of the substantia nigra (p<0.01). Hyperechogenic lesions of the caudate nucleus were associated with an increased signal intensity in T2 weighted MR images (p<0.05). All TCS parameters indicating brain atrophy correlated with CT findings (p<0.0001). CONCLUSIONS: TCS detects primarily abnormalities of the caudate nucleus and substantia nigra in Huntington's disease. These changes in the echotexture may represent degenerative changes in the basal ganglia matrix and are partially associated with CAG repeat expansion and the severity of clinical findings.

Adult↗

PubMed1993

Reduced basal ganglia volumes in Tourette's syndrome using three-dimensional reconstruction techniques from magnetic resonance images.

Using a 1.5-tesla GE Signa MR scanner, we imaged the brains of 14 right-handed Tourette's syndrome (TS) patients (11 men, three women), aged 18 to 49 years, who had minimal lifetime neuroleptic exposure. We also studied an equal number of normal controls individually matched for age, sex, and handedness and group-matched for socioeconomic status. We circumscribed basal ganglia on sequential axial images from spin-echo proton density-weighted acquisitions (TR 1,700, TE 20; slice thickness, 3 mm with 1.5-mm skip) and submitted the images for three-dimensional processing at a computer graphics workstation. Our hypothesis of lenticular nucleus volume reduction in TS was confirmed for the left- but not the right-sided nucleus. Post hoc analyses revealed smaller mean volumes of the caudate, lenticular, and globus pallidus nuclei compared with controls on both the right and left. Further analyses of basal ganglia asymmetry indices suggest that TS basal ganglia do not have the volumetric asymmetry (left greater than right) seen in normal controls. These findings confirm and extend prior phenomenologic, neuropathologic, and neuroradiologic studies that implicate the basal ganglia in the pathogenesis of TS.

Adult↗

PubMed2004

Role of the basal ganglia in category learning: how do patients with Parkinson's disease learn?

The purpose of the present study was to gain a deeper understanding of the role of the basal ganglia in learning and memory by examining learning strategies among patients with basal ganglia dysfunction. Using a probabilistic category learning task (the "weather prediction" task) previously shown to be sensitive to basal ganglia function, the authors examined patterns of performance during learning and used mathematical models to capture different learning strategies. Results showed that patients with Parkinson's disease exhibit different patterns of strategy use. Specifically, most controls initially used a simple, but suboptimal, strategy that focused on single-cue-outcome associations; eventually, however, most controls adopted a more complex, optimal learning strategy, integrating single-cue associations to predict outcomes for multiple-cue stimuli. In contrast, the majority of individuals with Parkinson's disease continued to rely on simple single-cue learning strategies throughout the experiment.

Aged↗

PubMed1995

Signal intensity on MRI of basal ganglia in multiple sclerosis.

It has been reported that a relative reduction in signal intensity on T2 weighted MRI may be seen in the basal ganglia of patients with multiple sclerosis and furthermore that this is due to excessive iron deposition. The basal ganglia are, however, rarely involved clinically or pathologically in multiple sclerosis, casting some doubt on this finding. Therefore MRI was carried out in 46 patients with definite multiple sclerosis and 42 age matched controls. Contiguous, 5 mm thick axial dual echo spin-echo images of the brain were obtained on a 1.5T imager. Visual rating scales were used to measure the lesion load as well as the signal intensity of the globus pallidus, putamen, caudate nucleus, substantia nigra, red nucleus, and thalamus. There was a mild degree of low signal intensity in the patient group in the thalamus only. The signal intensity of the thalamus and putamen was never lower than that of the globus pallidus. Low signal in the basal ganglia is rarely, if ever, found in multiple sclerosis and is not a useful radiological sign.

Adolescent↗

PubMed1997

Mnemonic functions of the basal ganglia.

A synthesis of older and recent work on mnemonic functions of the basal ganglia in rats, monkeys and humans emphasizes a reciprocal relationship of the caudate nucleus and putamen with the cerebral cortex, which mediates the memory of consistent relationships between stimuli and responses (sometimes called habits) that often involve relationships between the individual and its environment (egocentric memory). Evidence at several levels of analysis (including neuroplastic synaptic changes, activity of single neurons, and behavioral changes caused by lesions or neurochemical manipulations) implicate dopamine release from nigro-striatal neurons in the reinforcement, or strengthening, of neural representations in the basal ganglia.

Animals↗

PubMed1988

Pseudohypoparathyroidism, parkinsonism syndrome, with no basal ganglia calcification.

A 20 year old woman with pseudohypoparathyroidism, Parkinsonism and no basal ganglia calcifications shown by computed tomography is reported. She has typical features of pseudohypoparathyroidism and biochemical evidence of end-organ resistance to parathyroid hormone. She is mentally retarded and has tremor, rigidity, bradykinesia, and stooped posture. The cause of Parkinsonism in pseudohypoparathyroidism is thought to be basal ganglia calcification. This patient must have another pathophysiology, perhaps directly related to a G protein defect, causing impaired neurotransmission.

Adult↗

PubMed1995

Immunocytochemical localization of D1 and D2 dopamine receptors in the basal ganglia of the rat: light and electron microscopy.

The modulatory actions of dopamine on the flow of cortical information through the basal ganglia are mediated mainly through two subtypes of receptors, the D1 and D2 receptors. In order to examine the precise cellular and subcellular location of these receptors, immunocytochemistry using subtype specific antibodies was performed on sections of rat basal ganglia at both the light and electron microscopic levels. Both peroxidase and pre-embedding immunogold methods were utilized. Immunoreactivity for both D1 and D2 receptors was most abundant in the neostriatum where it was mainly contained within spiny dendrites and in perikarya. Although some of the immunoreactive perikarya had characteristics of interneurons, most were identified as medium-sized spiny neurons. Immunoreactivity for D1 receptor but not D2 receptor was associated with the axons of the striatonigral pathway and axons and terminals in the substantia nigra pars reticulata and the entopeduncular nucleus. In contrast, D2 immunoreactivity but not D1 immunoreactivity was present in the dopaminergic neurons in the substantia nigra pars compacta and ventral pars reticulata. In the globus pallidus, little immunoreactivity for either D1 or D2 receptor was detected. At the subcellular level, D1 and D2 receptor immunoreactivity was found to be mainly associated with the internal surface of cell membranes. In dendrites and spines immunoreactivity was seen in contact with the membranes postsynaptic to terminals forming symmetrical synapses and less commonly, asymmetrical synapses. The morphological features and membrane specializations of the terminals forming symmetrical synapses are similar to those of dopaminergic terminals previously identified by immunocytochemistry for tyrosine hydroxylase. In addition to immunoreactivity associated with synapses, a high proportion of the immunoreactivity was also on membranes at non-synaptic sites. It is concluded that dopamine receptor immunoreactivity is mainly associated with spiny output neurons of the neostriatum and that there is a selective association of D1 receptors with the so-called direct pathway of information flow through the basal ganglia, i.e. the striatoentopeduncular and striatonigral pathways. Although there is an association of receptor immunoreactivity with afferent synaptic inputs a high proportion is located at extrasynaptic sites.

Animals↗

PubMed2006

Basal ganglia oscillations and pathophysiology of movement disorders.

Low frequency rest tremor is one of the cardinal signs of Parkinson's disease and some of its animal models. Current physiological studies and models of the basal ganglia differ as to which aspects of neuronal activity are crucial to the pathophysiology of Parkinson's disease. There is evidence that neural oscillations and synchronization play a central role in the generation of the disease. However, parkinsonian tremor is not strictly correlated with the synchronous oscillations in the basal ganglia networks. Rather, abnormal basal ganglia output enforces abnormal thalamo-cortical processing leading to akinesia, the main negative symptom of Parkinson's disease. Parkinsonian tremor has probably evolved as a downstream compensatory mechanism.

Animals↗

PubMedDate not supplied

Postinfectious encephalomyelitis with localized basal ganglia involvement.

The diagnosis of postinfectious encephalomyelitis with symmetric lesions in the basal ganglia was confirmed by magnetic resonance imaging in 2 patients. A 7-year-old patient experienced severe dystonia and hyperreflexia; magnetic resonance imaging demonstrated bilateral lesions in the putamina and basis pontes. The other patient, a 2-year-old female, manifested hypotonia, facial grimacing, and athetosis. Symmetric lesions in the globus pallidus and substantia nigra were demonstrated by imaging studies. The nature and monophasic course of illness in these 2 patients, as well as the symmetric involvement of specific regions of the basal ganglia, may result from an immune-mediated postinfectious demyelinating process.

Basal Ganglia↗

PubMed1998

Gait variability and basal ganglia disorders: stride-to-stride variations of gait cycle timing in Parkinson's disease and Huntington's disease.

The basal ganglia are thought to play an important role in regulating motor programs involved in gait and in the fluidity and sequencing of movement. We postulated that the ability to maintain a steady gait, with low stride-to-stride variability of gait cycle timing and its subphases, would be diminished with both Parkinson's disease (PD) and Huntington's disease (HD). To test this hypothesis, we obtained quantitative measures of stride-to-stride variability of gait cycle timing in subjects with PD (n = 15), HD (n = 20), and disease-free controls (n = 16). All measures of gait variability were significantly increased in PD and HD. In subjects with PD and HD, gait variability measures were two and three times that observed in control subjects, respectively. The degree of gait variability correlated with disease severity. In contrast, gait speed was significantly lower in PD, but not in HD, and average gait cycle duration and the time spent in many subphases of the gait cycle were similar in control subjects, HD subjects, and PD subjects. These findings are consistent with a differential control of gait variability, speed, and average gait cycle timing that may have implications for understanding the role of the basal ganglia in locomotor control and for quantitatively assessing gait in clinical settings.

Adult↗

PubMed2004

Metabolite alterations in basal ganglia associated with psychiatric symptoms of abstinent toluene users: a proton MRS study.

Long-term toluene abuse causes a variety of psychiatric symptoms. However, little is known about abnormalities at the neurochemical level in the living human brain after long-term exposure to toluene. To detect neurochemical changes in the basal ganglia of subjects with a history of long-term toluene use, proton magnetic resonance spectroscopy (1H MRS) was performed in 12 abstinent toluene users and 13 healthy comparisons with no history of drug abuse. N-acetylaspartate (NAA), creatine plus phosphocreatine (Cr + PCr), choline-containing compounds (Cho), and myo-inositol (MI) levels were measured in the left and right basal ganglia. The Cho/Cr + PCr ratio, a marker of membrane metabolism, was significantly increased in the basal ganglia of toluene users in comparison to that of the control subjects. Furthermore, the increase in the Cho/Cr + PCr ratio was significantly correlated with the severity of residual psychiatric symptoms. These findings suggest that long-term toluene use causes membrane disturbance in the basal ganglia, which is associated with residual psychiatric symptoms that persist even after long-term abstinence from toluene use.

Adult↗

PubMed1994

Anatomical evidence for cerebellar and basal ganglia involvement in higher cognitive function.

The possibility that neurons in the basal ganglia and cerebellum innervate areas of the cerebral cortex that are involved in cognitive function has been a controversial subject. Here, retrograde transneuronal transport of herpes simplex virus type 1 (HSV1) was used to identify subcortical neurons that project via the thalamus to area 46 of the primate prefrontal cortex. This cortical area is known to be involved in spatial working memory. Many neurons in restricted regions of the dentate nucleus of the cerebellum and in the internal segment of the globus pallidus were labeled by transneuronal transport of virus from area 46. The location of these neurons was different from those labeled after HSV1 transport from motor areas of the cerebral cortex. These observations define an anatomical substrate for the involvement of basal ganglia and cerebellar output in higher cognitive function.

Animals↗

PubMed1995

Basal ganglia phosphorous metabolism in chronic schizophrenia.

OBJECTIVE: The authors examined whether there are abnormalities in high-energy phosphorous metabolism in the basal ganglia of schizophrenic patients. METHOD: In vivo 31P magnetic resonance spectroscopic imaging was performed on 18 chronic schizophrenic patients and 16 healthy comparison subjects. The percentages of total phosphorous signal for phosphomonoesters, inorganic phosphate, phosphodiesters, phosphocreatine, and beta-ATP were calculated. RESULTS: The mean percentages of beta-ATP signal in the right and left basal ganglia were significantly lower for the schizophrenic patients than for the comparison group. No other group differences in phosphorous metabolites and no lateral asymmetries in the schizophrenic group were noted. CONCLUSIONS: This preliminary study provides support for abnormal high-energy phosphorous metabolism in the basal ganglia of schizophrenic patients.

Adenosine Triphosphate↗

PubMed2002

Mental-rotation deficits following damage to the right basal ganglia.

The authors report the case of a woman with a right basal ganglia lesion and severe mental-rotation impairments. She had no difficulty recognizing rotated objects and had intact left-right orientation in egocentric space but was unable to map the left and right sides of external objects to her egocentric reference frame. This study indicates that the right basal ganglia may be critical components in a cortico-subcortical network involved in mental rotation. We speculate that the role of these structures is to select and maintain an appropriate motor program for performing smooth and accurate rotation. The results also have important implications for theories of object recognition by demonstrating that recognition of rotated objects can be achieved without mental rotation.

Aged↗