Developmental changes in spinal motoneuron dendrites in neonatal mice

Li, Yan; Brewer, Diana; Burke, Robert E.; Ascoli, Giorgio A.

doi:10.1002/cne.20438

Cited by 51 publications

(60 citation statements)

References 68 publications

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“…Osmoloarity was adjusted with D-manitol Motoneuron model. Using the anatomical data reported by Li et al (2005) for neonatal mouse motoneurons, we built a simplified model of a motoneuron to explore the possible distribution of Ca V 1.3 channels on motoneurons capable of reproducing the voltage and current recordings described in this study. The geometry of the motoneuron consisted of a somatic compartment with seven dendrites attached.…”

Section: Methodsmentioning

confidence: 99%

Staircase Currents in Motoneurons: Insight into the Spatial Arrangement of Calcium Channels in the Dendritic Tree

Carlin¹,

Bui²,

Dai³

et al. 2009

J. Neurosci.

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In spinal motoneurons, activation of dendritically located depolarizing conductances can lead to amplification of synaptic inputs and the production of plateau potentials. Immunohistochemical and computational studies have implicated dendritic Ca V 1.3 channels in this amplification and suggest that Ca V 1.3 channels in spinal motoneurons may be organized in clusters in the dendritic tree. Our goal was to provide physiological evidence for the presence of multiple discrete clusters of voltage-gated calcium channels in spinal motoneurons and to explore the spatial arrangement of these clusters in the dendritic tree. We recorded voltage-gated calcium currents from spinal motoneurons in slices of mature mouse spinal cords. We demonstrate that single somatic voltage-clamp steps can elicit multiple inward currents with varying delays to onset, resulting in a current with a "staircase"-like appearance. Recordings from cultured dorsal root ganglion cells at different stages of neurite development provide evidence that these currents arise from the unclamped portions of the dendritic tree. Finally, both voltage-and current-clamp data were used to constrain computer models of a motoneuron. The resultant simulations impose two conditions on the spatial distribution of Ca V channels in motoneuron dendrites: one of asymmetry relative to the soma and another of spatial separation between clusters of Ca V channels. We propose that this compartmentalization would provide motoneurons with the ability to process multiple sources of input in parallel and integrate this processed information to produce appropriate trains of action potentials for the intended motor behavior.

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Section: Methodsmentioning

confidence: 99%

Staircase Currents in Motoneurons: Insight into the Spatial Arrangement of Calcium Channels in the Dendritic Tree

Carlin¹,

Bui²,

Dai³

et al. 2009

J. Neurosci.

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“…In particular, the five files corresponded to rat hippocampal dentate gyrus granule cell 418882 from the Claiborne set (Rihn and Claiborne 1990), spinal mouse motoneuron ok_m88mod from the Ascoli set (Li et al 2005), and tiger salamander retinal ganglion cells MART, LAR2, and mp_tv_01193_gc from the Miller set (Toris et al 1995). In each of these models we implemented the same Hodgkin-Huxley (HH)-type spike-generating mechanism.…”

Section: E T H O D Smentioning

confidence: 99%

“…4A1, 5A1, and 6A1): a rat hippocampal granule cell (Rihn and Claiborne 1990), a mouse spinal motoneuron (Li et al 2005), and a tiger salamander retinal ganglion (RG) cell (Toris et al 1995). These simulations were all run with a 5-Hz spiking activity and under two levels of dendritic excitability: passive (0% HH) and partially active (50% HH).…”

Section: Synaptic Efficacy In Model Neurons With Real Morphologiesmentioning

confidence: 99%

Dendritic Excitability and Neuronal Morphology as Determinants of Synaptic Efficacy

Komendantov

Ascoli²

2009

Journal of Neurophysiology

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Komendantov AO, Ascoli GA. Dendritic excitability and neuronal morphology as determinants of synaptic efficacy. J Neurophysiol 101: 1847-1866, 2009. First published January 28, 2009 doi:10.1152/jn.01235.2007. The ability to trigger neuronal spiking activity is one of the most important functional characteristics of synaptic inputs and can be quantified as a measure of synaptic efficacy (SE). Using model neurons with both highly simplified and real morphological structures (from a single cylindrical dendrite to a hippocampal granule cell, CA1 pyramidal cell, spinal motoneuron, and retinal ganglion neurons) we found that SE of excitatory inputs decreases with the distance from the soma and active nonlinear properties of the dendrites can counterbalance this global effect of attenuation. This phenomenon is frequency dependent, with a more prominent gain in SE observed at lower levels of background inputoutput neuronal activity. In contrast, there are no significant differences in SE between passive and active dendrites under higher frequencies of background activity. The influence of the nonuniform distribution of active properties on SE is also more prominent at lower background frequencies. In models with real morphologies, the effect of active dendritic conductances becomes more dramatic and inverts the SE relationship between distal and proximal locations. In active dendrites, distal synapses have higher efficacy than that of proximal ones because of arising dendritic spiking in thin branches with high-input resistance. Lower levels of dendritic excitability can make SE independent of the distance from the soma. Although increasing dendritic excitability may boost SE of distal synapses in real neurons, it may actually reduce overall SE. The results are robust with respect to morphological variation and biophysical properties of the model neurons. The model of CA1 pyramidal cell with realistic distributions of dendritic conductances demonstrated important roles of hyperpolarization-activated (h-) current and A-type K ϩ current in controlling the efficacy of single synaptic inputs and overall SE differently in basal and apical dendrites. I N T R O D U C T I O NDendrites play a central role in neuronal information processing. Electrical signals from other neurons are transmitted onto dendrites via synaptic inputs, which are located throughout the dendritic tree. The most important functional characteristic of synaptic inputs is their ability to influence neuronal spiking activity. At a strong excitatory synapse, a single action potential (AP) in the presynaptic cell might trigger an AP in the postsynaptic neuron, whereas at a weak excitatory synapse only a subthreshold excitatory postsynaptic potential (EPSP) would be initiated under the same stimulating conditions. In real neuronal networks an individual neuron receives many synaptic inputs from numerous other neurons. Under the appropriate circumstance of background activity, even an individual weak synaptic input can be the determining factor for AP initiation...

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“…To determine whether RSV infects neuronal cells and the importance of G protein or the G protein CX3C motif for infection, primary cortical neuronal cultures were prepared from 16-day-old embryos of Swiss-Webster mice (Harlan Sprague-Dawley, Indianapolis, IN) as described previously (1,10,11). Briefly, mice were euthanized, the neocortexes were collected and digested with trypsin, and the neuronal cells were plated onto culture wells treated with poly-D-lysine (50 g/ml).…”

mentioning

confidence: 99%

Respiratory Syncytial Virus (RSV) Infects Neuronal Cells and Processes That Innervate the Lung by a Process Involving RSV G Protein

Li¹,

Alvarez

et al. 2006

J Virol

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Respiratory syncytial virus (RSV) is a primary cause of morbidity and life-threatening lower respiratory tract disease in infants and young children. Children with acute RSV bronchiolitis often develop respiratory sequelae, but the disease mechanisms are poorly understood. Mounting evidence suggests that RSV may mediate persistent infection. Using immunohistochemistry to identify RSV and RSV-infected cell types, we show that RSV infects primary neurons and neuronal processes that innervate the lungs through a process that involves RSV G protein and the G protein CX3C motif. These findings suggest a mechanism for disease chronicity and have important implications for RSV disease intervention strategies.

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Developmental changes in spinal motoneuron dendrites in neonatal mice

Cited by 51 publications

References 68 publications

Staircase Currents in Motoneurons: Insight into the Spatial Arrangement of Calcium Channels in the Dendritic Tree

Staircase Currents in Motoneurons: Insight into the Spatial Arrangement of Calcium Channels in the Dendritic Tree

Dendritic Excitability and Neuronal Morphology as Determinants of Synaptic Efficacy

Respiratory Syncytial Virus (RSV) Infects Neuronal Cells and Processes That Innervate the Lung by a Process Involving RSV G Protein

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