SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The fibre pathways associated with the basal ganglia include through-conduction lines and side-loops associated with the striatum, pallidum and substantia nigra. Each of these regions is now known to contain subdivisions differing from one another in the neurotransmitter-related compounds they contain. This paper includes an outline of these new findings and a commentary on some of their functional implications.
Four aspects of a possible association between essential tremor (ET) and Parkinson's disease (PD) were investigated: (1) the frequency of extrapyramidal signs in ET; (2) the frequency of concurrent ET and PD (i.e., monosymptomatic postural tremor for 5 or more years prior to onset of PD); (3) the frequency of ET in the families of PD patients; and (4) the frequency of PD in families of ET patients. Two hundred and thirty-seven ET patients (137 in London and 100 in Chicago) were evaluated. One hundred patients with PD and 100 normal control subjects were also investigated. Mild extrapyramidal signs occurred in only 4.5% of ET patients and were consistent with those found in normal aging. Only 3% of PD patients gave a history of uncomplicated ET. There was no difference in the frequency of a family history of PD between ET patients, a group of PD patients, and control subjects. Frequency of a family history of ET was higher among PD patients than control subjects, although the difference was not statistically significant. These data indicate that there is no association or genetic link between ET and PD.
Extrapyramidal signs frequently accompany Alzheimer's disease (AD), but the pathological substrate remains unknown. Clinical and postmortem information from patients with AD, Parkinson's disease, or progressive supranuclear palsy and control subjects seen at a large tertiary medical center between 1989 and 1994 was examined. AD patients who had taken neuroleptics and AD brains that also contained Lewy bodies were excluded. The presence of extrapyramidal signs was determined using the Unified Parkinson's Disease Rating Scale. Sections of basal ganglia, subthalamic nucleus, and substantia nigra were examined for neurofibrillary tangles and neuropil threads and the nigra for neuronal numbers. Patients with AD (with or without extrapyramidal signs) did not show neuronal loss in the nigra compared to control subjects, while both Parkinson's disease and progressive supranuclear palsy brains showed marked depletion. The number of neurofibrillary tangles and neuropil threads was increased in AD (with or without extrapyramidal signs) nigra compared to control tissue, and also in progressive supranuclear palsy nigra, but not Parkinson's disease nigra. The numbers of nigral neurofibrillary tangles and neuropil threads were positively related to extrapyramidal signs in AD. There were no correlations between tangles and threads in the basal ganglia or subthalamic nucleus and extrapyramidal signs in AD. Thus, extrapyramidal signs in AD correlate best with tangle pathology in the nigra and do not require the concomitant presence of Lewy bodies.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The organization of afferent projections to the lateral habenular nucleus (LHB) was studied in adult cats. In autoradiographic experiments, tritiated leucine injections were made into regions shown in retrograde transport studies to project to LHB (lateral hypothalamus, preoptic region, entopeduncular nucleus, and midbrain raphe) to determine the locations of axonal trajectories and terminal zones. The distribution of silver grains in the ipsilateral LHB differed according to the injection site. Entopeduncular nucleus projected to the ventrolateral part, raphe to the dorsomedial part, preoptic region to the central part, anterior hypothalamus to all but the ventrolateral part, and posterior hypothalamus to all but the dorsomedial part. The lateral hypothalamus, preoptic region, and anterior portion of the entopeduncular nucleus projected primarily through the inferior thalamic peduncle and stria medullaris, while the posterior portion of the entopeduncular nucleus projected more diffusely through thalamus to enter LHB from its ventral aspect. Raphe axons reached LHB through the fasciculus retroflexus. Entopeduncular and lateral hypothalamic axons passed through the habenular commissure to the contralateral stria medullaris to reach the contralateral LHB. Silver grains in LHB were distributed similarly bilaterally, but were much less dense contralateral to the injection. The major afferent projections to the feline LHB are therefore topographically organized. The significance of this organization in relation to the possible role of the LHB in integrating limbic and extrapyramidal motor systems is discussed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The T2 of brain tissue is known to be field dependent, decreasing as B0 increases. Previous studies have attributed reduced T2 in the structures of the extrapyramidal motor system (EPMS) to high iron concentrations. The present study was designed to manipulate physiologic iron concentrations and study the effects on T2 and on the field dependence of T2 at 7.0 T in whole formalin-fixed brains. A rat model was devised in which iron concentrations in the structures of interest were altered by diet manipulation. Cerebral structures with different iron content were imaged and T2 measured with MR microscopy at both 2.0 and 7.0 T. T2 of all tissues was shorter by 40%-60% at 7.0 T. Although some dependence of T2 on iron concentration was evident, it was less than expected. The strongest correlation was in the substantia nigra. The highest-resolution studies, at 30 x 30 x 50 microns, show the myelin bundles in many of the EPMS structures but not in the substantia nigra. From these data, it appears that T2 at greater field strengths depends more on susceptibility-induced spin dephasing imposed by diffusion through the tissue microstructure than on the presence of iron.
Explore the source record for details and available documents.
Wilson's disease is a rare autosomal recessive disorder characterized by the accumulation of copper, mainly in the liver and the brain. As copper accumulation in the brain leads to disturbances in basal ganglia function, neurological-type patients typically present with hypo- and hyperkinetic extrapyramidal symptoms, with Parkinsonism being very common. Although there are numerous reports on olfactory deficits in primary neurodegenerative disorders, olfactory function has not been investigated in metabolic disorders presenting with extrapyramidal features. Twenty-four patients with Wilson's disease participated in the investigation. All patients were treated pharmacologically. They comprised patients with liver disease alone (including mild enzyme elevation in asymptomatic individuals; n = 11) and/or neurological symptoms (n = 13) at the time of testing. Twenty-one patients underwent both [18F]fluoro-2-deoxy-D-glucose positron emission tomography ([18F]FDG-PET) and magnetic resonance imaging (MRI). The severity of extrapyramidal symptoms was judged using a clinical score system ranging from 0 (no symptoms) to 3 (severe symptoms). In all patients, psychophysical testing was performed using the Sniffin' Sticks, which involved tests for odor threshold, discrimination, and identification. Results from the present study revealed that Wilson's disease patients with neurological symptoms show a significant olfactory dysfunction compared to hepatic-type patients. Individuals who are more severely neurologically affected also present with a more pronounced olfactory deficit. Of interest, there was no significant effect of long-term treatment with penicillamine on olfactory function. Olfactory function did not correlate significantly with the presence of MRI visible lesions in the basal ganglia or with any regional glucose metabolism as measured by [18]F-FDG-PET. In conclusion, these findings indicate that the underlying pathological alterations with degeneration in the basal ganglia and neuronal loss in association with a marked increase of the copper content in this brain region play a role in the olfactory deficit.
A 48-year-old man presented with a progressive gait disorder. He had longstanding ataxia, oculomotor apraxia, motor delay, and cognitive impairment, diagnosed as cerebral palsy. Physical examination revealed ataxia, oculomotor apraxia, extrapyramidal signs, and a wide-based, shuffling gait. Magnetic resonance imaging showed vermian aplasia, consistent with Joubert syndrome. Positron emission tomography scan revealed normal fluorodopa uptake, but elevated raclopride binding, compatible with dopamine deficiency. This case demonstrates that a patient with Joubert syndrome may survive into adulthood and present as a chronic neurologic disorder with subacute extrapyramidal signs.