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PubMed1988

Technetium-99m HMPAO imaging in patients with basal ganglia disease.

Technetium 99m hexamethylpropylene-amine oxime (HMPAO) is trapped by cerebral grey matter and the basal ganglia on its first pass through the brain. To assess its potential for studying patients with diseases of the basal ganglia, a study of 15 normal volunteers and 32 patients with known or suspected basal ganglia disease have been investigated. Sixteen patients with idiopathic Parkinson's disease showed no abnormality of the basal ganglia and varying degrees of cerebral underperfusion consistent with their intellectual status. Eight patients with Huntington's chorea showed a characteristic pattern of reduced or absent caudate nucleus uptake. Patients with diseases affecting the basal ganglia, such as Fahr's disease, Wilson's disease and hemibalismus had varying degrees of basal ganglia underperfusion as demonstrated by an HMPAO scan. We believe that this new radiopharmaceutical for the demonstration of cerebral blood flow shows significant potential for the diagnosis and management of patients with basal ganglia disease.

Adult↗
PubMed1994

Basal ganglia: functional anatomy and physiology. Part 1.

Advances in knowledge about basal ganglia structure and connectivity from 1925 to date are reviewed. Current concepts about neuronal populations, transmitters, and input and output of each of the basal ganglia nuclei are presented. The portrayal by Wilson, in 1925, of the striatum as a simple homogeneous structure has been replaced by the recognition, based on staining characteristics, connectivity, and function, that the neostriatum is compartmentalized into striosomes, matrisomes, and matrix compartments. Electrophysiologic studies have further shown the existence, in the neostriatum, of neuronal clusters that represent basic functional units much like the functional columns described much earlier for the cerebral cortex. Whereas the neostriatum is considered the major receiving area of the basal ganglia, the globus pallidus and substantia nigra pars reticulata constitute the major output nuclei. Combined neuroanatomic and neurophysiologic studies have revealed precise somatotopic organization throughout the basal ganglia system such that the leg, arm, and face areas of the cerebral cortex related to respective topographic areas within the striatum, pallidum, substantia nigra, and subthalamus. The previous concept of an inhibitory role for dopamine on striatal neurons has been modified. It is now acknowledged that dopamine exerts an inhibitory effect on striatal neurons that project to the external pallidum and a facilitatory effect on striatal neurons that project to the internal pallidum and substantia nigra pars reticulata. The previous concept of serial connectivity of the neostriatum (funnel concept) has been replaced by the concept of parallel connectivity. Within the internal connectivity of the basal ganglia, there is a fast system in which the neurotransmitter is gamma-aminobutyric acid (GABA) and a slow system modulated by neuropeptides. The slow system is believed to give identity to an otherwise homogenous GABAergic system.

Basal Ganglia↗
PubMed2004

Network-level neuroplasticity in cortico-basal ganglia pathways.

The striatum, the largest input nucleus of the basal ganglia, receives massive inputs from the neocortex and thalamus, and gives rise to the direct, indirect and striosomal pathways of the basal ganglia. Here, the view is developed that the striatum is a major site for adaptive plasticity in cortico-basal ganglia circuits, affecting in the normal state a broad range of behaviours. This plasticity can become a major source of maladaptive responses in disease states affecting the basal ganglia.

Animals↗
PubMed2003

Childhood onset generalised dystonia can be modelled by increased gain in the indirect basal ganglia pathway.

Clinical experience suggests an important role of the indirect basal ganglia pathway in the genesis of childhood onset generalised dystonia, but it has been difficult to reconcile the increased muscle activity in dystonia with the current model of basal ganglia function in which the indirect pathway is considered primarily inhibitory. The aim of this study was to present a modification of the direct-indirect pathway model, in which the indirect pathway is inverting rather than purely inhibitory, so that while high signals are inhibited, low signals are amplified. As the basal ganglia may be a feedback loop that modifies cortical activity, instability from excessive gain in this feedback loop could explain features of dystonia. A detailed mathematical model is provided, together with simulations of cortical cell population spiking behaviour when connected through a basal ganglia loop. The simulations show that increased gain in the indirect pathway relative to the direct pathway can lead to unstable uncontrolled synchronous oscillations in cortex and basal ganglia. This behaviour could result in dystonia. The model provides a consistent explanation for the association of dystonia with parkinsonism and disorders characterised by dopamine depletion, the ability to treat some dystonias with dopamine, the ability of neuroleptic drug treatment to cause an acute dystonic reaction treatable with anticholinergic drugs, and the ability of pallidotomy or deep brain stimulation of the internal pallidum to alleviate symptoms of generalised dystonia.

Basal Ganglia↗
PubMed1995

Chemical anatomy of primate basal ganglia.

This paper provides an overview of the anatomical and functional organization of the most prominent chemospecific neuronal systems that compose the basal ganglia in primates. Emphasis is placed on the heterogeneity and diversity of small-molecule transmitters, neuroactive peptides and proteins used by basal ganglia neurons. Dopaminergic, serotoninergic and cholinergic neuronal systems are shown to comprise multiple subsystems organized according to highly specific patterns. These subsystems differentially regulate gene expression of several neuroactive peptides, including tachykinins, enkephalins, dynorphin, somatostatin, and neuropeptide Y, that are used by distinct subsets of basal ganglia neurons. Glutamatergic excitatory inputs establish distinct functional territories within the basal ganglia, and neurons in each of these territories act upon other brain neuronal systems through a GABAergic disinhibitory output mechanism. A striking complementary pattern of distribution of the calcium-binding proteins parvalbumin and calbindin D-28k is noted in all basal ganglia components. The limbic system-associated membrane protein (LAMP) is confined chiefly to basal ganglia sectors that are anatomically and functionally related to limbic system structures; these may serve as functional interfaces between the basal ganglia and the limbic system. The functional status of the various basal ganglia chemospecific systems in neurodegenerative diseases, such as Parkinson's disease and Huntington's chorea, is examined. It is concluded that these multiple transmitter-related systems cannot be analyzed separately as they form highly complex and interactive neuronal networks. These complexities should be taken into account to reach a better understanding of the functions of primate basal ganglia in health and disease.

Animals↗
PubMed1998

Basal ganglia organization in amphibians: chemoarchitecture.

Recent studies dealing with the investigation of the afferent and efferent connections of the basal ganglia of amphibians have revealed many similarities with basal ganglia structures of amniotes. In a further step, the chemoarchitecture of basal ganglia of the frog Rana perezi has been investigated. For use as main markers of amphibian basal ganglia structures, antibodies against tyrosine hydroxylase, substance P, and enkephalin were selected. Moreover, the distributions of nitric oxide synthase (nicotinamide adenine dinucleotide phosphate-diaphorase histochemistry), calretinin, dopamine-beta-hydroxylase, choline acetyltransferase, mesotocin, vasotocin, somatostatin, neuropeptide Y, neuropeptide FF, and serotonin were studied to corroborate a comparison with both basal ganglia and amygdaloid structures of amniotes. On the basis of connections and chemoarchitecture, a striatum proper, nucleus accumbens, dorsal and ventral pallidum, bed nucleus of the stria terminalis, and amygdaloid complex have been identified. Accordingly, a new terminology is proposed that is in line with our current understanding of basal ganglia organization in amphibians.

Amygdala↗
PubMed1996

Neuropsychological alterations in patients with computed tomography-detected basal ganglia calcification.

OBJECTIVE: To investigate the cognitive and mental status of patients with basal ganglia calcification on a computed tomographic scan. DESIGN: Eighteen ambulatory patients with basal ganglia calcification and without other radiological findings who were identified from the computed tomography records of a general hospital in a 2-year period and 16 control subjects who were matched for age, education, sex, and premorbid IQ estimation consented to participate. All subjects underwent a neurological evaluation, a comprehensive neuropsychological battery, and tests with psychiatric rating scales. RESULTS: Significant differences for the control group were found in tests that evaluated motor speed and executive, visuospatial, and some memory functions. Four patients (22%) met criteria for organic mood disorder (minor depression, three patients; bipolar depression, one patient) according to the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition, whereas six other patients (33%) met diagnostic criteria for obsessive-compulsive disorder. CONCLUSIONS: These results indicate that patients with basal ganglia calcifications frequently have a subcortical pattern of neuropsychological dysfunction and behavioral changes that are known to be associated with alterations of the frontal-limbic-basal ganglia circuits. The pattern of neuropsychological impairment is consistent with basal ganglia damage. However, poor performance in other neuropsychological tests suggest additional involvement of other connected networks.

Adult↗
PubMed2001

Schizophrenia and familial idiopathic basal ganglia calcification: a case report.

BACKGROUND: Familial idiopathic basal ganglia calcification (FIBGC) is generally associated with neurological and psychiatric symptoms. An association between FIBGC and schizophrenia has been described but it remains uncertain. We studied the relationship between the presence and extent of basal ganglia calcification and schizophrenia in a multiply affected family. METHOD: Symmetrical basal ganglia calcifications (BGC) were detected on computerized tomography (CT) in a schizophrenic proband and led us to carry out CTs and standardized psychiatric evaluations (SADS--Endicott & Spitzer, 1978) in all available first-degree relatives (mother and six siblings). RESULTS: Five subjects had BGC, including three subjects diagnosed as schizophrenic. Three subjects had no BGC and none of them was diagnosed as schizophrenic. We subdivided the BGC into three groups: massive (pallidum, striatum and dentate nuclei affected); medium (pallidum and striatum); and mild (pallidum only). The two subjects with massive BGC and one of the two with medium BGC had schizophrenia. The subject with mild BGC had no psychotic symptoms. CONCLUSION: Our results are consistent with the hypothesis that BGC favours the occurrence of a schizophrenia-like syndrome and that the risk of occurrence of this syndrome is proportional to the extent of calcification. These findings support the hypothesis that schizophrenia is determined by a disruption of thalamo-cortico-striatal circuits.

Adult↗
PubMed1987

A proposed mechanism for the production of skeletalmotor positioning movements by the basal ganglia.

A programming function for the Basal Ganglia is suggested by implicating them in the production of positioning movements during directed skeletalmotor movements. The Association Cortex (especially the Prefrontal) sends a signal which is an internal representation of the desired end position of a movement to the Caudate. The Sensorimotor Cortex sends feedback from the commands for the primary movement to the Putamen, this representing the end position to be attained by the primary movement. These two signals are integrated in the Lateral Pallidal Segment producing a signal coding the magnitude and possibly the timing of positioning movements. This signal is sent to the Subthalamic Nucleus, which distributes it to the two main output areas of the Basal Ganglia and hence to affect motor and postural pathways.

Animals↗
PubMed2006

PET imaging of the basal ganglia.

The present chapter reviews PET imaging in basal ganglia disorders; Parkinson's disease is used as a model of these disorders because the neurochemical pathobiology of this disease is well known and great advances in the imaging area have been achieved. Other basal ganglia disorders including Tourette's syndrome, dystonia, Huntington's chorea and Wilson's disease are also dealt with. With PET and SPECT techniques, the whole integrative dopaminergic network of neurons can be studied, which plays an important role in differential diagnostics. Furthermore, pharmacological effects of medication can be visualized and the role of stereotaxic neurosurgery can be evaluated. Finally, functional imaging gives clues about the prognosis and rehabilitation aspects of the basal ganglia disorders.

Basal Ganglia↗
PubMed1994

Organization of N-methyl-D-aspartate glutamate receptor gene expression in the basal ganglia of the rat.

Glutamate is an important neurotransmitter in the circuitry of the basal ganglia. Of the four pharmacological classes of receptors that may mediate the actions of glutamate, the N-methyl-D-aspartate (NMDA) type is of particular interest insofar as it has been implicated in the neural processes underlying long-term synaptic plasticity as well as excitotoxic injury. NMDA ligand binding sites are abundant in the structures of the basal ganglia, and NMDA receptors have been linked to neuronal excitability, neuropeptide gene expression, and regulation of dopamine release in these regions. NMDA receptors are believed to be heterooligomers of subunits from two families: NMDAR1, encoded by a single gene but alternatively spliced to produce eight distinct isoforms (NMDAR1A-H), and NMDAR2, encoded by four separate genes (NMDAR2A-D). We have used in situ hybridization with a total of 13 oligonucleotide probes to examine the expression of these genes in the rat basal ganglia. NMDAR1 subunits are expressed throughout the basal ganglia as well as in the rest of the brain; however, the alternatively spliced amino-terminal region Insertion I is abundantly expressed only in the subthalamic nucleus and is not detectable in the neostriatum, globus pallidus, or substantia nigra pars compacta. In contrast, expression of the carboxy terminus segment Deletion I is prominent in the striatum but is not observed in other elements of the basal ganglia. NMDAR2 subunits also exhibit differential expression: NMDAR2B is abundant in the striatum, but NMDAR2A is present within the striatum only at low levels. NMDAR2C is present in the substantia nigra pars compacta only, while NMDAR2D exhibits an unusual distribution, with high levels of expression in the substantia nigra pars compacta, the subthalamic nucleus, the globus pallidus, and the ventral pallidum. Since each isoform of the NMDAR1 and NMDAR2 subunits can confer distinct properties on the resultant NMDA receptor, these data imply that there is a high degree of regional specialization in the properties of NMDA receptors within the basal ganglia.

Animals↗
PubMed2003

How is firing activity of substantia nigra cells regulated? Relevance of pattern-code in the basal ganglia.

The current model of the basal ganglia (BG) assumes that neurons use a firing rate renewal code for movement computing under normal and pathological conditions. Here, we report nonrenewal firing (neuronal firing is influenced by its own previous activity) in cells of the anesthetized rat's substantia nigra (SN). Both compensatory (short interspike intervals (ISIs) are followed by long ISIs and vice versa) and persistent (short and long ISIs cluster for long time periods) nonrenewal activity was found in 52.6% and 33.8% of SN cells, respectively. A compensatory pattern was found in 77.7% of DA cells, but in only 9.8% of GABA-cells. Conversely, a persistent pattern was observed in 74.6% of GABAergic cells and in only 9.9% of DA cells. These findings indicate two types of nonrenewal firing pattern codes specifically present in SN dopaminergic and GABAergic neurons. Disruption of these patterns may play a role in the pathophysiology of basal ganglia disorders such as Parkinson's disease and dyskinesias.

Action Potentials↗
PubMed1999

Thalamic interaction between the input and the output systems of the basal ganglia.

The striatal return through the thalamus is largely neglected in current studies dealing with basal ganglia function, and its role within this circuitry remains obscure. In this contribution the thalamus is regarded as an important place of interaction between the input and the output organization of the basal ganglia. In support of this idea, a brief overview is provided of some of the most recent findings concerning the thalamus in relation to the basal ganglia circuitry. In particular, we have focused on the thalamostriatal projections themselves, on the output of the basal ganglia to the thalamus and also on the overlapping territories between the thalamic projection of the output nuclei and the thalamostriatal neurons. These data support the existence of several thalamic feedback circuits within the basal ganglia neural system. Finally, some considerations are provided upon the functional significance of these thalamic feedback circuits in the overall organization of the basal ganglia.

Animals↗
PubMed2000

Basal ganglia output and cognition: evidence from anatomical, behavioral, and clinical studies.

The traditional view that the basal ganglia are simply involved in the control of movement has been challenged in recent years. Three lines of evidence indicate that the basal ganglia also are involved in nonmotor operations. First, the results of anatomical studies clearly indicate that the basal ganglia participate in multiple circuits or 'loops' with cognitive areas of the cerebral cortex. Second, the activity of neurons within selected portions of the basal ganglia is more related to cognitive or sensory operations than to motor functions. Finally, in some instances basal ganglia lesions cause primarily cognitive or sensory disturbances without gross motor impairments. In this report, we briefly review some of these data and present a new anatomical framework for understanding the basal ganglia contributions to nonmotor function.

Basal Ganglia↗
PubMed2001

Anatomical MRI study of basal ganglia in bipolar disorder patients.

This study examined possible anatomical abnormalities in basal ganglia structures in bipolar disorder patients. Caudate and putamen gray matter volumes, and globus pallidus total volume were measured with magnetic resonance imaging (MRI) in 22 DSM-IV bipolar patients (age+/-S.D.=36+/-10 years; eight drug-free and 14 lithium monotherapy patients) and 22 matched healthy control subjects (age+/-S.D.=38+/-10 years). No significant differences were found between bipolar patients and healthy control subjects for any of the basal ganglia measures (t-tests, P>0.05). Age was inversely correlated with left putamen volumes in patients (R=-0.44, P=0.04), but not in healthy control subjects (R=-0.33, P=0.14). Older patients (>36 years old) had a significantly larger left globus pallidus than younger ones (< or =36 years old) (ANOVA, P=0.01). In a multiple regression analysis, after entering age as independent variable, the length of illness predicted smaller left putamen volumes, explaining 10.4% of the variance (F=4.07, d.f.=2, P=0.03). No significant effects of episode type, number of prior episodes, or gender were found in any basal ganglia measurements (ANOVA, P>0.05). In conclusion, our findings indicate that the basal ganglia may be anatomically preserved in bipolar patients. This is in contrast to available findings for unipolar disorder. However, our findings also suggest that age and length of illness may have significant effects on basal ganglia structures in bipolar patients, which may be more pronounced among bipolar I patients, and of relevance for the pathophysiology of the disorder.

Adult↗
PubMed2005

Basal Ganglia calcification in mitochondrial disorders.

Though basal ganglia calcification (BGC) has been recognized as a feature of mitochondriopathy, little is known about its frequency in a larger cohort. The aim of this work was to assess the frequency of BGC, type and frequency of clinical and additional imaging central-nervous-system (CNS) abnormalities and of non-CNS abnormalities in mitochondriopathy patients with BGC. Retrospectively reviewed were the records of all mitochondriopathy patients in whom BGC was found on cerebral CT during 10 years. Among those who underwent cerebral CT, thirty-six, 24 women, 12 men, aged 33-93 years, showed BGC. The most frequent clinical CNS manifestations in these patients were epilepsy (n = 9), Parkinson syndrome (n = 9), dementia (n = 7), dysarthria (n = 5), spasticity (n = 4), tremor (n = 4), or stroke (n = 4). Additional cerebral CT-findings were atrophy (n = 10), lacunas (n = 6), leucaraiosis (n = 6), focal gliosis (n = 4), or stroke (n = 1). MR imaging, carried out in 12 patients, confirmed BGC in one. The 36 patients presented with involvement of the CNS (n = 32), endocrine system (n = 29), peripheral nervous system (n = 28), heart (n = 23), inner ear (n = 16), eyes (n = 15), guts (n = 11), blood (n = 9), kidney (n = 2), or dermis (n = 2). BGC occurs in one sixth of non-selected patients with mitochondriopathy and is associated with clinical and imaging CNS abnormalities and multisystem disease in the majority of them.

Adult↗
PubMed2000

Development of the nigrostriatal dopamine neuron and the pathways in the basal ganglia.

The nigrostriatal (NS) dopamine (DA) neuron and the basal ganglia show marked functional age variation in the first three decades. Neurohistochemical studies revealed marked age variation of activities of tyrosine hydroxylase at the terminal of the NS-DA neuron, which show exponential decremental variation from early childhood and subside in the fourth decade. DA-D2 receptors, examined by PET scan, are in high levels in the third decade which decrease dramatically to the bottom or 'adult' levels in the fourth decade. The examination of voluntary saccade suggested the striatal indirect pathways are functionally immature in the childhood and attain adult levels in around the middle of the second decade, while the striatal direct pathways have already been functionally matured in childhood. Clinical evidence suggests that among efferents of the basal ganglia those descending to the brainstem and the midbrain mature earlier while those ascending to the thalamus later. These developmental variation of the NS-DA neurons and the basal ganglia could modulate the ages at onset and clinical courses of the diseases with abnormalities in the NS-DA neuron or the basal ganglia which occur in these age periods.

Adolescent↗
PubMed2003

Multiregional 1H-MRSI of the hippocampus, thalamus, and basal ganglia in schizophrenia.

BACKGROUND: The hippocampus, thalamus and basal ganglia are among the brain regions of major interest in schizophrenia. AIMS: The purpose of this study was to corroborate previous findings of reduced N-acetylaspartate in the hippocampal and thalamic regions and to investigate possible metabolite changes in the putamen in schizophrenia. METHOD: MRSI study of the thalamus, basal ganglia, and hippocampus in 13 schizophrenic patients under stable medication and age-matched healthy controls. RESULTS: A decrease of the N-acetylaspartate signal was found in the hippocampal region and the thalamus but not in the putamen of patients compared to controls. No significant group differences in the signals from creatine and phosphocreatine, and choline-containing compounds were found in the hippocampal region and the putamen but the signal from choline-containing compounds was decreased in the thalamus of patients. CONCLUSION: Metabolic processes in the basal ganglia of schizophrenic patients seem to be opposite the hippocampal and thalamus findings.

Adult↗