Comparison of cortically and subcortically controlled motor systems: I. Morphology of intracellularly filled rubrospinal neurons in rat and turtle

Lustig, Daniel G.; Herrick, James L.; Keifer, Joyce

doi:10.1002/(sici)1096-9861(19980713)396:4<521::aid-cne8>3.0.co;2-3

“…We identified only ≈10% of the axons of projection neurons. This was consistent with earlier findings in Golgi studies in the macaque (King et al, 1971) and recent observations of rubrospinal cells labeled intracellularly with LY/biocytin in the rat (Lustig et al, 1998). With many neurons, the likely reason was that the axon was lopped near the soma, and its “stump” was not differentiated from a truncated primary dendrite segment.…”

Section: Resultssupporting

confidence: 92%

Geometry of rubrospinal, rubroolivary, and local circuit neurons in the macaque red nucleus

Burman

¹

,

Darian‐Smith

²

,

Darian‐Smith

³

2000

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The primate red nucleus consists of three main neuron subpopulations, namely, rubrospinal neurons in the magnocellular nucleus, rubroolivary cells in the parvocellular nucleus, and local circuit neurons in both subnuclei: Each subpopulation has unique cerebellar and neocortical inputs. The structural framework for the interactions of these rubral subpopulations remains poorly defined and was the focus of this study in six macaques. Somata of rubrospinal neurons, dorsolateral-spinal (DL-spinal) neurons, as defined in the accompanying paper (Burman et al. [2000] J. Comp. Neurol., this issue), and rubroolivary neurons were labeled retrogradely first with Fast Blue injected either into the cervical spinal cord or the inferior olive. The soma/dendrite profiles of selected cells (53 rubrospinal, 19 DL-spinal, and 17 rubroolivary cells) were visualized by the intracellular injection of Lucifer Yellow/biocytin in fixed slices (400 microm thick) of midbrain. The descriptive statistics of the somata and the dendritic arborization of each rubral neuron type were established. Projection neuron subpopulations had similar but differentiable soma/dendrite profiles, with four to six slender, spine-bearing dendritic trees radiating out approximately 400 microm from the soma. Twelve presumed interneurons, all in the parvocellular nucleus, differed from projection neurons in that they had smaller somata and many slender, spine-bearing segments that constituted the multibranching dendrite profile that radiated out approximately 250 microm from the soma. A tentative model of the macaque rubral microcircuitry was developed, and its functional implications were explored. It incorporated 1) the known topography of the nucleus and its connections, 2) our data specifying the soma/dendrite morphology of the three main rubral neuron types, and 3) the ultrastructure reported by other laboratories of intrarubral synaptic connections.

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“…We identified only Ϸ10% of the axons of projection neurons. This was consistent with earlier findings in Golgi studies in the macaque (King et al, 1971) and recent observations of rubrospinal cells labeled intracellularly with LY/biocytin in the rat (Lustig et al, 1998). With many neurons, the likely reason was that the axon was lopped near the soma, and its "stump" was not differentiated from a truncated primary dendrite segment.…”

Section: Assessing Whether a Neuron Injected With Ly/biocytin Is Wellsupporting

confidence: 91%

Geometry of rubrospinal, rubroolivary, and local circuit neurons in the macaque red nucleus

Burman¹,

Darian‐Smith²,

2000

View full text Add to dashboard Cite

The primate red nucleus consists of three main neuron subpopulations, namely, rubrospinal neurons in the magnocellular nucleus, rubroolivary cells in the parvocellular nucleus, and local circuit neurons in both subnuclei: Each subpopulation has unique cerebellar and neocortical inputs. The structural framework for the interactions of these rubral subpopulations remains poorly defined and was the focus of this study in six macaques. Somata of rubrospinal neurons, dorsolateral-spinal (DL-spinal) neurons, as defined in the accompanying paper (Burman et al. [2000] J. Comp. Neurol., this issue), and rubroolivary neurons were labeled retrogradely first with Fast Blue injected either into the cervical spinal cord or the inferior olive. The soma/dendrite profiles of selected cells (53 rubrospinal, 19 DL-spinal, and 17 rubroolivary cells) were visualized by the intracellular injection of Lucifer Yellow/biocytin in fixed slices (400 microm thick) of midbrain. The descriptive statistics of the somata and the dendritic arborization of each rubral neuron type were established. Projection neuron subpopulations had similar but differentiable soma/dendrite profiles, with four to six slender, spine-bearing dendritic trees radiating out approximately 400 microm from the soma. Twelve presumed interneurons, all in the parvocellular nucleus, differed from projection neurons in that they had smaller somata and many slender, spine-bearing segments that constituted the multibranching dendrite profile that radiated out approximately 250 microm from the soma. A tentative model of the macaque rubral microcircuitry was developed, and its functional implications were explored. It incorporated 1) the known topography of the nucleus and its connections, 2) our data specifying the soma/dendrite morphology of the three main rubral neuron types, and 3) the ultrastructure reported by other laboratories of intrarubral synaptic connections.

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“…The dendritic complexity was analyzed by a Scholl analysis (Lustig et al, 1998). Low-magnification pictures were taken of an NB-filled PN, and a set of concentric circles, each 50 m apart, was superimposed on the PN with the cell body in the center of the circles.…”

Section: Methodsmentioning

confidence: 99%

Cytoplasmic Polyadenylation Element Binding Protein 1-Mediated mRNA Translation in Purkinje Neurons Is Required for Cerebellar Long-Term Depression and Motor Coordination

McEvoy¹,

Cao²,

Llopis³

et al. 2007

Journal of Neuroscience

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The ability of neurons to modify synaptic connections is critical for proper brain development and function in the adult. It is now clear that changes in synaptic strength are often accompanied by changes in synaptic morphology. This synaptic plasticity can be maintained for varying lengths of time depending on the type of neuronal activity that first induced the changes. Long-term synaptic plasticity requires the synthesis of new proteins, and one mechanism for the regulation of experience-induced protein synthesis in neurons involves cytoplasmic polyadenylation element binding protein (CPEB1). CPEB1 can bidirectionally regulate mRNA translation, first repressing translation, and then activating translation after the phosphorylation of two critical residues (T 171 and S 177). To determine the full extent of CPEB1-mediated protein synthesis in synaptic function, we engineered a line of mice expressing CPEB1 with these phosphorylation sites mutated to alanines (mCPEB1-AA) exclusively in cerebellar Purkinje neurons (PNs). Thus, mRNAs bound by mCPEB1-AA would be held in a translationally dormant state. We show that mCPEB1-AA localizes to synapses in cerebellum and resulted in a loss of protein synthesis-dependent phase of parallel fiber-PN long-term depression. This was accompanied by a change in spine number and spine length that are likely attributable in part to the dysregulation of IRSp53, a protein known to play a role in synaptic structure. Finally, mCPEB1-AA mice displayed a significant impairment of motor coordination and a motor learning delay.

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Comparison of cortically and subcortically controlled motor systems: I. Morphology of intracellularly filled rubrospinal neurons in rat and turtle

Cited by 5 publications

References 35 publications

Geometry of rubrospinal, rubroolivary, and local circuit neurons in the macaque red nucleus

Geometry of rubrospinal, rubroolivary, and local circuit neurons in the macaque red nucleus

Geometry of rubrospinal, rubroolivary, and local circuit neurons in the macaque red nucleus

Cytoplasmic Polyadenylation Element Binding Protein 1-Mediated mRNA Translation in Purkinje Neurons Is Required for Cerebellar Long-Term Depression and Motor Coordination

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