The functional anatomy of basal ganglia disorders.
TL;DR: A model in which specific types of basal ganglia disorders are associated with changes in the function of subpopulations of striatal projection neurons is proposed, which suggests that the activity of sub Populations of Striatal projections neurons is differentially regulated by striatal afferents and that different striatal projections may mediate different aspects of motor control.
About: This article is published in Trends in Neurosciences.The article was published on 1989-01-01 and is currently open access. It has received 5094 citations till now. The article focuses on the topics: Medium spiny neuron & Indirect pathway of movement.
Citations
More filters
TL;DR: Recent evidence indicating that a parallel functional architecture may also be characteristic of the organization within each individual circuit is discussed, which represents a significant departure from earlier concepts of basal ganglia organization.
4,011Â citations
TL;DR: This paper describes the changes in neuronal activity in the motor circuit in animal models of hypo- and hyperkinetic disorders and postulates specific disturbances within the basal ganglia-thalamocortical 'motor' circuit.
3,623Â citations
TL;DR: The differential effects of dopamine on striatonigral and striatopallidal neurons are mediated by their specific expression of D1 and D2 dopamine receptor subtypes, respectively.
Abstract: The striatum, which is the major component of the basal ganglia in the brain, is regulated in part by dopaminergic input from the substantia nigra. Severe movement disorders result from the loss of striatal dopamine in patients with Parkinson's disease. Rats with lesions of the nigrostriatal dopamine pathway caused by 6-hydroxydopamine (6-OHDA) serve as a model for Parkinson's disease and show alterations in gene expression in the two major output systems of the striatum to the globus pallidus and substantia nigra. Striatopallidal neurons show a 6-OHDA-induced elevation in their specific expression of messenger RNAs (mRNAs) encoding the D2 dopamine receptor and enkephalin, which is reversed by subsequent continuous treatment with the D2 agonist quinpirole. Conversely, striatonigral neurons show a 6-OHDA-induced reduction in their specific expression of mRNAs encoding the D1 dopamine receptor and substance P, which is reversed by subsequent daily injections of the D1 agonist SKF-38393. This treatment also increases dynorphin mRNA in striatonigral neurons. Thus, the differential effects of dopamine on striatonigral and striatopallidal neurons are mediated by their specific expression of D1 and D2 dopamine receptor subtypes, respectively.
2,946Â citations
TL;DR: It now appears that at the level of the putamen such inputs remain segregated within the "motor" circuit, and it is difficult to imagine how such functional specificity could be maintained in the absence of strict topographic specificity within the sequential projections that comprise these two circuits.
Abstract: The central theme of the "segregated circuits" hypothesis is that structural convergence and functional integration occurs within, rather than between, each of the identified circuits Admittedly, the anatomical evidence upon which this scheme is based remains incomplete The hypothesis continues to be predicated largely on comparisons of anterograde and retrograde labeling studies carried out in different sets of animals Only in the case of the "motor" circuit has evidence for the continuity of the loop been demonstrated directly in individual subjects; for the other circuits, such continuity is inferred from comparisons of data on different components of each circuit obtained in separate experiments Because of the marked compression of pathways leading from cortex through basal ganglia to thalamus, comparisons of projection topography across experimental subjects may be hazardous Definitive tests of the hypothesis of maintained segregation await additional double- and multiple-label tract-tracing experiments wherein the continuity of one circuit, or the segregation of adjacent circuits, can be examined directly in individual subjects It is worthy of note, however, that the few studies to date that have employed this methodology have generated results consistent with the segregated circuits hypothesis Moreover, single cell recordings in behaving animals have shown striking preservation of functional specificity at the level of individual neurons throughout the "motor" and "oculomotor" circuits It is difficult to imagine how such functional specificity could be maintained in the absence of strict topographic specificity within the sequential projections that comprise these two circuits This is not to say, however, that we expect the internal structure of functional channels (eg, the "arm" channel within the "motor" circuit) to have cable-like, point-to-point topography When the grain of analysis is sufficiently fine, anatomical studies have shown repeatedly that the terminal fields of internuclear projections (eg, to striatum, pallidum, nigra, thalamus, etc) often appear patchy and highly divergent, suggesting that neighboring groups of projection cells tend to influence interdigitating clusters of postsynaptic neurons While more intricate and complex than simple point-to-point topography, however, this type arrangement should also be capable of maintaining functional specificity As discussed briefly above, it is not yet clear to what extent the inputs to the "motor" circuit from the different precentral motor fields (eg, MC, SMA, APA) are integrated in their passage through the circuit It now appears that at the level of the putamen such inputs remain segregated(ABSTRACT TRUNCATED AT 400 WORDS)
2,659Â citations
TL;DR: The hypothesis states that the basal ganglia do not generate movements, and when voluntary movement is generated by cerebral cortical and cerebellar mechanisms, the basal Ganglia act broadly to inhibit competing motor mechanisms that would otherwise interfere with the desired movement.
2,420Â citations
References
More filters
TL;DR: The basal ganglia serve primarily to integrate diverse inputs from the entire cerebral cortex and to "funnel" these influences, via the ventrolateral thalamus, to the motor cortex.
Abstract: Information about the basal ganglia has accumulated at a prodigious pace over the past decade, necessitating major revisions in our concepts of the structural and functional organization of these nuclei. From earlier data it had appeared that the basal ganglia served primarily to integrate diverse inputs from the entire cerebral cortex and to "funnel" these influences, via the ventrolateral thalamus, to the motor cortex (Allen & Tsukahara 1974, Evarts & Thach 1969, Kemp & Powell 1971). In particular, the basal
8,111Â citations
Book•
01 Jun 1991
TL;DR: The Neurology of Eye Movements: Characteristics and Teleology by R. John Leigh, M.D., and David S. Zee MD as mentioned in this paper is a survey of eye movement.
Abstract: The Neurology of Eye Movements, Edition 5, by R. John Leigh, M.D. and David S. Zee MD Foreword Chapter 1: A Survey of Eye Movements: Characteristics and Teleology Chapter 2: The Ocular Motor Periphery Chapter 3: The Vestibular-Optokinetic System Chapter 4: The Saccadic System Chapter 5: Smooth Visual Tracking and Fixation Chapter 6: Gaze Holding and The Neural Integrator Chapter 7: The Neural Basis for Conjugate Eye Movements Chapter 8: Eye-Head Movements Chapter 9: Vergence Eye Movements Chapter 10: Diagnosis of Peripheral Ocular Motor Palsies And Strabismus Chapter 11: Diagnosis of Nystagmus and Saccadic Intrusions Chapter 12: Diagnosis and Management of Vestibular Disorders Chapter 13: Disorders of Ocular Motility Due To Disease of the Brainstem, Cerebellum and Diencephalon Chapter 14: Disorders of Ocular Motility With Disease Affecting The Basal Ganglia, Cerebral Cortex, And In Systemic Conditions Appendix A: A Summary Scheme for the Bedside Ocular Motor Examination Appendix B: A Summary of Methods for Measuring Eye Movements Appendix C: Tables of Ocular Motor Findings in Hereditary Ataxias Appendix D: Table of Videos and their Legends
2,824Â citations
TL;DR: A progressive brain disease featured by supranuclear ophthalmoplegia affecting chiefly vertical gaze, pseudobulbar palsy, dysarthria, dystonic rigidity of the neck and upper trunk, and other less constant cerebellar and pyramidal symptoms.
Abstract: Introduction In this report we are describing a progressive brain disease featured by supranuclear ophthalmoplegia affecting chiefly vertical gaze, pseudobulbar palsy, dysarthria, dystonic rigidity of the neck and upper trunk, and other less constant cerebellar and pyramidal symptoms. Dementia has usually remained mild. This disease would appear to be predominantly a nerve cell degeneration centered chiefly in the brain stem. The fully developed clinical picture presented by this disease seems to follow a fairly definitive pattern and does not conform to the classical system degenerations such as motor neurone disease, paralysis agitans, cerebellar degeneration, Creuzfeldt-Jakob disease, or the presenile dementias. Yet it would seem unlikely that the disease shown by our cases is a new one, and similar earlier cases may well have been accepted as arteriosclerotic parkinsonism when that diagnosis was used in a very broad sense such as in Critchley's monograph of 1929. 1 There are some resemblances to
1,572Â citations
[...]
TL;DR: Experimental NeurologyBy Prof. Paul Glees.
Abstract: Experimental Neurology By Prof Paul Glees Pp xii + 532 (Oxford: Clarendon Press; London: Oxford University Press, 1961) 75s net
1,559Â citations
TL;DR: The Neurology of Eye Movements, Edition 5, by R. John Leigh, M.D. and David S. Zee MD is published.
Abstract: The Neurology of Eye Movements, Edition 5, by R. John Leigh, M.D. and David S. Zee MD Foreword Chapter 1: A Survey of Eye Movements: Characteristics and Teleology Chapter 2: The Ocular Motor Periphery Chapter 3: The Vestibular-Optokinetic System Chapter 4: The Saccadic System Chapter 5: Smooth Visual Tracking and Fixation Chapter 6: Gaze Holding and The Neural Integrator Chapter 7: The Neural Basis for Conjugate Eye Movements Chapter 8: Eye-Head Movements Chapter 9: Vergence Eye Movements Chapter 10: Diagnosis of Peripheral Ocular Motor Palsies And Strabismus Chapter 11: Diagnosis of Nystagmus and Saccadic Intrusions Chapter 12: Diagnosis and Management of Vestibular Disorders Chapter 13: Disorders of Ocular Motility Due To Disease of the Brainstem, Cerebellum and Diencephalon Chapter 14: Disorders of Ocular Motility With Disease Affecting The Basal Ganglia, Cerebral Cortex, And In Systemic Conditions Appendix A: A Summary Scheme for the Bedside Ocular Motor Examination Appendix B: A Summary of Methods for Measuring Eye Movements Appendix C: Tables of Ocular Motor Findings in Hereditary Ataxias Appendix D: Table of Videos and their Legends
1,333Â citations