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PubMed1997

Pigeon basal ganglia: insights into the neuroanatomy underlying telencephalic sensorimotor processes in birds.

This paper reviews the organization of the avian and mammalian striatum. The striatum receives input from virtually the entire rostrocaudal and mediolateral expanse of the cerebral cortex. The corticostriatal projections appear to be glutamatergic, forming excitatory synapses in the striatum. Another major projection to the avian striatum that also appears to be glutamatergic stems from a set of nuclei in the dorsal zone of the avian thalamus that are comparable to the mammalian intralaminar, mediodorsal, and midline nuclei. Furthermore, the striatum receives a massive projection from dopaminergic neurons of the ventral tegmental area and substantia nigra in the midbrain tegmentum. In return, the midbrain tegmentum receives a direct GABAergic/substance P-ergic/ dynorphinergic projection from the striatum, as well as an indirect one formed by GABAergic/substance P-ergic/ dynorphinergic and GABA-ergic/enkephalinergic striatal neurons projecting to the pallidum in the first step, and pallidal GABAergic/LANT6/parvalbumin neurons projecting to the midbrain tegmentum in the second step. In addition to its projection neurons, the striatum possesses GABAergic and cholinergic interneurons. One motor output pathway of the striatum runs via the pallidum and dorsal thalamic ventral tier nulei to the motor cortex. In addition to this pathway, birds possess a major descending pathway from the basal ganglia to the tectum via the GABAergic nucleus spiriformis lateralis in the pretectum. On hodological and topological grounds, similar nuclei, although not GABAergic, can be found in mammals. Finally, an other striatal motor output is formed by a sequential GABAergic pathway from the basal ganglia via the substantia nigra to the tectum. In conclusion, it appears that the organization of the avian and mammalian basal ganglia is similar rather than different.

Animals↗
PubMed2006

Altered frontocortical, cerebellar, and basal ganglia activity in adjuvant-treated breast cancer survivors 5-10 years after chemotherapy.

PURPOSE: To explore the relationship of regional cerebral blood flow and metabolism with cognitive function and past exposure to chemotherapy for breast cancer. PATIENTS AND METHODS: Subjects treated for breast cancer with adjuvant chemotherapy remotely (5-10 years previously) were studied with neuropsychologic testing and positron emission tomography (PET), and were compared with control subjects who had never received chemotherapy. [O-15] water PET scans was acquired during performance of control and memory-related tasks to evaluate cognition-related cerebral blood flow, and [F-18] fluorodeoxyglucose (FDG) PET scans were acquired to evaluate resting cerebral metabolism. PET scans were analyzed by statistical parametric mapping and region of interest methods of analysis. RESULTS: During performance of a short-term recall task, modulation of cerebral blood flow in specific regions of frontal cortex and cerebellum was significantly altered in chemotherapy-treated subjects. Cerebral activation in chemotherapy-treated subjects differed most significantly from untreated subjects in inferior frontal gyrus, and resting metabolism in this area correlated with performance on a short-term memory task previously found to be particularly impaired in chemotherapy-treated subjects. In examining drug-class specific effects, metabolism of the basal ganglia was significantly decreased in tamoxifen + chemotherapy-treated patients compared with chemotherapy-only breast cancer subjects or with subjects who had not received chemotherapy, while chemotherapy alone was not associated with decreased basal ganglia activity relative to untreated subjects. CONCLUSION: Specific alterations in activity of frontal cortex, cerebellum, and basal ganglia in breast cancer survivors were documented by functional neuroimaging 5-10 years after completion of chemotherapy.

Adult↗
PubMed1996

Immature teratoma in the cerebral basal ganglia of an adult.

A 19-year-old male underwent an emergent operation for a massive brain tumor in the right cerebral basal ganglia. However, brain herniation had already developed and he subsequently died. Histological examination showed the tumor consisted of immature epithelial arrangements and glandular structures, considered as immature teratoma containing choriocarcinomatous components. Such an immature teratoma arising in the cerebral basal ganglia in an adult is very rare.

Adult↗
PubMed1995

MR imaging of the basal ganglia in chronic liver disease: correlation of T1-weighted and magnetisation transfer contrast measurements with liver dysfunction and neuropsychiatric status.

Conventional T1-weighted spin echo (T1WSE) and T1-weighted magnetization transfer (MT) images were obtained in 26 patients with biopsy-proven cirrhosis (nine Child's grade A, 10 Child's grade B and seven Child's grade C). Four subjects showed no evidence of neuropsychiatric impairment on clinical, psychometric and electrophysiological testing, seven showed evidence of subclinical hepatic encephalopathy and 15 were classified as having overt hepatic encephalopathy. Signal intensities of basal ganglia nuclei (head of caudate, putamen, globus pallidus and thalamus) and adjacent brain parenchyma were measured and contrast calculated. On T1WSE imaging, contrast measurements of the globus pallidus were significantly greater in patients with neuropsychiatric dysfunction than in those who were unimpaired (p < 0.05). This was not observed in the other basal ganglia nuclei. Patients with subclinical and overt hepatic encephalopathy could not be distinguished on the basis of contrast measurements of the globus pallidus or of any other nucleus. T1WSE contrast measurements of the globus pallidus were increased with elevations in blood ammonia levels (p < 0.05) and with the severity of liver dysfunction, when graded according to the Pugh's score (p < 0.05) Those patients with the worst liver injury (Child's grade C) had significantly greater T1WSE pallidal contrast measurements (p < 0.05) than those patients with minimal liver injury (Child's grade A). The patients with intermediate liver damage (Child's grade B) could not be distinguished from the other two groups. While MT imaging highlighted the basal ganglia and showed a correlation between globus pallidus contrast and blood ammonia levels (p < 0.05), no other relationship between MT contrast measurements and either the degree of hepatic encephalopathy or the severity of liver dysfunction was found.

Adult↗
PubMed2005

Subcortical loops through the basal ganglia.

Parallel, largely segregated, closed-loop projections are an important component of cortical-basal ganglia-cortical connectional architecture. Here, we present the hypothesis that such loops involving the neocortex are neither novel nor the first evolutionary example of closed-loop architecture involving the basal ganglia. Specifically, we propose that a phylogenetically older, closed-loop series of subcortical connections exists between the basal ganglia and brainstem sensorimotor structures, a good example of which is the midbrain superior colliculus. Insofar as this organization represents a general feature of brain architecture, cortical and subcortical inputs to the basal ganglia might act independently, co-operatively or competitively to influence the mechanisms of action selection.

Animals↗
PubMed2000

Basal ganglia involvement in memory-guided movement sequencing.

The basal ganglia (BG) are thought to play a critical role in motor planning and movement sequencing. While electrophysiological and imaging studies have shown that the dorso-lateral prefrontal cortex (DLPFC) is involved in working memory (WM), the involvement of the BG in this process is not well understood. We used a motor sequencing task to investigate the differential role of BG nuclei in memory-guided movement. Significant activation was observed in the DLPFC and posterior putamen and globus pallidus (GP), with a trend in the caudate and no differences in the anterior putamen. We then investigated the effect of BG outflow on thalamic activation using functional connectivity analysis. Activation in the posterior putamen + GP was found to be correlated with thalamic activation only in the hemisphere contralateral to movement. These results provide the first fMRI evidence that the BG may modulate activity in the thalamus during working memory-guided movement sequencing. Our findings suggest that the BG activation may reflect increased motor sequencing demands during the memory-guided movement condition and, specifically, that the posterior putamen and GP may play a role in maintenance of representations in WM in a manner that contributes to planning and temporal organization of motor sequencing.

Adult↗
PubMed2006

Competition between feedback loops underlies normal and pathological dynamics in the basal ganglia.

Experiments performed in normal animals suggest that the basal ganglia (BG) are crucial in motor program selection. BG are also involved in movement disorders. In particular, BG neuronal activity in parkinsonian animals and patients is more oscillatory and more synchronous than in normal individuals. We propose a new model for the function and dysfunction of the motor part of BG. We hypothesize that the striatum, the subthalamic nucleus, the internal pallidum (GPi), the thalamus, and the cortex are involved in closed feedback loops. The direct (cortex-striatum-GPi-thalamus-cortex) and the hyperdirect loops (cortex-subthalamic nucleus-GPi-thalamus-cortex), which have different polarities, play a key role in the model. We show that the competition between these two loops provides the BG-cortex system with the ability to perform motor program selection. Under the assumption that dopamine potentiates corticostriatal synaptic transmission, we demonstrate that, in our model, moderate dopamine depletion leads to a complete loss of action selection ability. High depletion can lead to synchronous oscillations. These modifications of the network dynamical state stem from an imbalance between the feedback in the direct and hyperdirect loops when dopamine is depleted. Our model predicts that the loss of selection ability occurs before the appearance of oscillations, suggesting that Parkinson's disease motor impairments are not directly related to abnormal oscillatory activity. Another major prediction of our model is that synchronous oscillations driven by the hyperdirect loop appear in BG after inactivation of the striatum.

Action Potentials↗
PubMed2006

A three-dimensional, histological and deformable atlas of the human basal ganglia. I. Atlas construction based on immunohistochemical and MRI data.

This paper describes the construction of an atlas of the human basal ganglia. The successive steps of the construction were as follows. First a postmortem specimen was subjected to a MRI acquisition prior to extraction of the brain from the skull. The brain was then cryosectioned (70 microm thickness). One section out of ten (80 sections) was Nissl-stained with cresyl violet, another series of 80 sections was immunostained for the calcium binding protein calbindin. Contours of basal ganglia nuclei including their calbindin-stained functional subdivisions, fiber bundles and ventricles (n=80 structures) were traced from histological sections and digitized. A novelty of this atlas is the MRI acquisition, which represents the core data element of the study. MRI was used for the coregistration of the atlas data and permitted, through multimodal (Nissl, calbindin, images of cryosectioning, T1 and T2 MRI) and 3D optimization, the production of anatomically and geometrically consistent 3D surfaces, which can be sliced through any desired orientation. The atlas MRI is also used for its deformation to provide accurate conformation to the MRI of living patients, thus adding information at the histological level to the patient's MRI volume. This latter aspect will be presented in a forthcoming paper.

Basal Ganglia↗
PubMed1988

Association of dopamine D1 and D2 receptors with specific cellular elements in the basal ganglia of the cat: the uneven topography of dopamine receptors in the striatum is determined by intrinsic striatal cells, not nigrostriatal axons.

To ascertain the cellular associations of the D1 and D2 dopamine receptor subtypes in components of the basal ganglia, cats were prepared with unilateral, axon-sparing, ibotenic acid lesions of the striatum (n = 6) or lesions of the nigrostriatal dopamine system by intranigral infusion of 6-hydroxydopamine (n = 8). After 42 days survival, tissue sections from the brains were processed for quantitative, in vitro receptor autoradiography with [3H]SCH23390 (D1 radioligand) or [3H]spiroperidol (D2 radioligand). Lesion-induced changes in basal ganglia nuclei were assessed by comparing them to the corresponding nuclei on the intact side and in naive brains. Ibotenate lesions cause a decline in specific D1 and D2 receptor-binding in the area of the striatal lesion of 94% and 85%, respectively, and completely eliminate the uneven patterns of high- and low-density binding that are characteristic of the cat's caudate nucleus. The globus pallidus, entopeduncular nucleus and pars reticulata of the substantia nigra also show marked reductions in binding after striatal ibotenate lesions. Thus, after caudate nucleus lesions, D2 binding in the two pallidal segments declines by approximately 50%, but remains unchanged in the substantia nigra. Binding of the D1 radioligand (which is not measurable in the globus pallidus) declines by about 75% in the affected regions of the entopeduncular nucleus and pars reticulata, and by about 30% in the pars compacta. Lesions of the nigral dopamine neurons reduce D2 receptor-binding by 95% in the pars compacta and 40% in the pars reticulata, but have no effect on the concentration of D1 or D2 radioligand-binding in the striatum or pallidum. Moreover, such lesions failed to alter the uneven patterns of binding in the striatum. These data suggest that most, if not all, D1 receptors in the basal ganglia are associated with cells of the striatum and their axons in the entopeduncular nucleus and substantia nigra, and likewise, a large majority of D2 receptors are associated with striatal cells and their axons in pallidal structures. Nearly all D2 receptors in the substantia nigra are associated with dopamine neurons (autoreceptors). Finally, the heterogeneous patterns of D1 and D2 receptors in the striatum are a consequence of intrinsic neuronal distributions.

Animals↗
PubMedDate not supplied

[Bilateral hypodensity of the basal ganglia. Clinico-evolutionary correlation in children].

INTRODUCTION: The presence in neuroimaging of areas of symmetrical bilateral hypodensity in the basal ganglia (SBHBG) is a striking and unusual finding. OBJECTIVE: To determine the aetiology, clinical significance and evolution of a group of paediatric patients with SBHBG. PATIENTS AND METHODS: We made a study of 21 patients with neuroimaging studies (CT or MR) showing SBHBG. The affected area was related to the aetiology, clinical features and evolution. RESULTS: The ages varied between 4 months and 16 years. In 7 cases Leigh s disease was diagnosed, 5 had had acute hypoxia, 4 type I glutaric aciduria, and 1 case each of methylmalonic aciduria, Ia gluconeogenesis, CO intoxication, acute striatal necrosis and bacterial meningitis. The putamen was affected in 6 cases, globus pallidus in 4 cases and the lenticular nucleus was damaged in the rest. Three cases also had lesions in the caudate nucleus. MR was better than CT for localization of the precise area involved. Clinically, 13 cases had extrapyramidal signs. We found no relation between the size, localization of the lesion and the prognosis, which was more dependent on the aetiology, only one patient (CO intoxication) recovered and eight died (Leigh s disease and 1 case of hypoxia). CONCLUSIONS: The presence of SBHBG in a patient makes extensive study necessary to find the aetiology. It is a nonspecific finding, usually of metabolic origin and with little correlation with the clinical condition. Its presence implies a poor prognosis and raises suspicion of the presence of certain neurological disorders.

Adolescent↗
PubMed1986

Do enkephalins in basal ganglia mediate a physiological motor rest mechanism?

Thermal injury (30-s immersion in water at 62 degrees C) of one hind limb of rats caused a gradual withdrawal of the limb from use, such that after 1 week 50% of the animals walked on three legs. At 24 h following thermal lesion and at a time when the lesioned paw was still used for walking there was a reduction in met- and leu-enkephalin content in the periaqueductal grey (PAG) and bilateral reduction in leu-enkephalin content of the globus pallidus, but no change in enkephalin levels in caudate-putamen. One week following the lesion, animals exhibiting complete withdrawal of the injured limb, showed bilateral reduction of met- and leu-enkephalin content of PAG. Both met- and leu-enkephalin content in caudate-putamen. In each case the change was more marked in basal ganglia areas contralateral to the lesion. In animals lesioned 1 week previously and which did not use the injured limb, there was no change in the monoamine (or metabolite) content of caudate-putamen or in the spontaneous or potassium-evoked release of 3H-dopamine from strial slices. Thermal injury did not cause any general change in pain sensitivity and the time of change in pain threshold in the injured limb did not parallel the withdrawal of the affected limb from walking. The results suggest that after a thermal limb lesion, delayed changes in basal ganglia enkephalin content may be important in withdrawing the injured limb from the normal pattern of locomotion. Basal ganglia enkephalins may be involved in a physiological rest mechanism, which allows healing of the affected part.

Animals↗
PubMed1987

The organization of nucleus tegmenti pedunculopontinus neurons projecting to basal ganglia and thalamus: a retrograde fluorescent double labeling study in the rat.

The organization of nucleus tegmenti pedunculopontinus (PPN) projections to the basal ganglia and thalamus was studied in the rat by using retrograde transport of fluorescent dyes. Fast blue was injected into the substantia nigra (SN) while Nuclear yellow was delivered to one of the following nuclei: globus pallidus (GP), entopeduncular nucleus, subthalamic nucleus (STN) or parafascicular nucleus of the thalamus. Retrogradely labeled cells were observed throughout the PPN without topographical arrangement. The cells labeled from the SN outnumbered those labeled from other structures. In all cases the majority of cells were single labeled and only a few cells double labeled from SN-GP or SN-STN were found. Labeled cells were either fusiform or multipolar in shape. These data suggest that distinct PPN cells project to their basal ganglia and thalamic targets without a prominent branched organization.

Amidines↗
PubMed2006

Functional role of the basal ganglia in the planning and execution of actions.

OBJECTIVE: Recent studies of functional brain imaging have shown the involvement of the basal ganglia in executive processes such as planning and set-shifting. However, the specific contributions of the striatum in those processes remain unknown. This study aimed to test the hypothesis that the caudate nucleus is primarily involved in the preparation of a novel action and not in set-shifting per se. METHODS: In the present event-related functional magnetic resonance imaging (fMRI) study, a new task was developed that permitted, for the first time, to distinguish between shifts in classification when the rule is implicitly given by the task from shifts that require cognitive comparison and planning. RESULTS: Significantly increased activity in the caudate nucleus and the putamen was observed only in conditions in which cognitive planning was required to perform a set-shift, whereas significant activation was seen in the subthalamic nucleus (another region of the basal ganglia) in all shifting conditions whether or not planning was required. INTERPRETATION: We suggest that the caudate nucleus and the putamen are particularly important, respectively, in the planning and the execution of a self-generated novel action, whereas the subthalamic nucleus may be required when a new motor program is solicited independently of the choice of strategy.

Adolescent↗
PubMedDate not supplied

Bilateral symmetrical basal ganglia infarction after intravenous use of cocaine and heroin.

A case is reported of a young man who developed bilateral symmetrical basal ganglia infarcts after intravenous use of cocaine and heroin. Ischemic infarcts of the brain are a known complication of to cocaine use, alone or in combination with heroin (speed balling). This symmetrical occurrence of infarction, however, is unusual and has not been reported after cocaine use.

Adult↗
PubMed1981

Clinical significance of basal ganglia calcifications detected by ct (a retrospective study of 33 cases).

In a retrospective study 2015 CT scans were studied for the presence of basal ganglia calcifications. These were discovered in 33 cases. No abnormalities in serum calcium or phosphate levels or any other specific clinical symptoms related to these calcifications were found. It is concluded that basal ganglia calcifications casually detected by CT generally have no clinical significance.

Adult↗
PubMed2001

Contrast optimization of Macaca mulatta basal ganglia in magnetic resonance images at 4.7 Tesla.

To determine whether high field MRI could distinguish among the different regions of the basal ganglia, the brains of two Macaca mulatta monkeys were explored in vivo using a 4.7 T MR imager. Gradient-echo (GE) and spin-echo images were acquired with proton-density, T1 and T2* weightings. Five GE images with increased susceptibility effects were generated using a GESFID sequence, from which T2* maps were also reconstructed. The first echo of the GESFID sequence (TE = 12.6 ms) produced the best contrast-to-noise ratio (C/N) between the pallidum and the putamen, the pallidum and the thalamus, the substantia nigra and the surrounding white matter, and the substantia nigra and the subthalamic nucleus. An increased T2*-weighting (TE = 37.2 ms) was necessary to maximize C/N between the putamen and the surrounding white matter, and between the subthalamic nucleus and the surrounding white matter. A dual GE sequence with a short TE ( approximately 10 ms) and a longer one ( approximately 30 ms) thus effectively localizes basal ganglia subregions at 4.7 T.

Animals↗
PubMed2000

Substantia nigra glutamate antagonists produce contralateral turning and basal ganglia Fos expression: interactions with D1 and D2 dopamine receptor agonists.

Experiments measuring behavior and immediate-early gene expression in the basal ganglia can reveal interactions between dopamine (DA) and glutamate neurotransmission. Nigrostriatal DA projections influence two striatal efferent pathways that, in turn, directly and indirectly influence the activity of the substantia nigra pars reticulata (SNr). This report tests the interactions between striatal DA receptors and nigral glutamate receptors on basal ganglia function by examining both contralateral turning and Fos immunoreactivity in striatum and pallidum following unilateral intranigral microinfusions of glutamate antagonists given to intact and 6-OHDA-lesioned rats. The NMDA antagonist AP5 (1 microg), or the AMPA/kainate antagonist DNQX (0.015-1.5 microg), injected into the SNr (0.5 microl) elicited contralateral turning as well as both striatal and pallidal Fos expression. Moreover, intranigral DNQX elicited more turning and greater numbers of Fos-positive striatal neurons in 6-OHDA-lesioned animals than in unlesioned controls, suggesting that the 6-OHDA injection induces functional changes in nigral glutamate transmission. In 6-OHDA-lesioned rats, systemic injections of the DA D1 receptor agonist SKF38393 (0.5 mg/kg, i.p.) increased striatal Fos expression due to intranigral DNQX. In contrast, the D2 agonist quinpirole (0.1 mg/kg, i.p.) decreased striatal Fos expression but increased the pallidal Fos arising from intranigral AP5. In additional experiments, both intact and 6-OHDA-lesioned rats were given simultaneous intranigral and intrastriatal infusions and turning and pallidal Fos expression were measured. 6-OHDA-lesioned rats given 5 microg of intrastriatal quinpirole exhibited both turning and pallidal Fos that was significantly increased by intranigral AP5. These results indicate that the opposing influences of D2 agonists and endogenous nigral glutamate transmission are mediated by striatal D2 receptors. Finally, the behavioral effects of intranigral glutamate antagonism can be dissociated from the effects on striatal or pallidal immediate-early gene expression.

Animals↗