scholarly journals Spinal motor neurons are regenerated after mechanical lesion and genetic ablation in larval zebrafish

Development ◽  
2016 ◽  
Vol 143 (9) ◽  
pp. 1464-1474 ◽  
Author(s):  
Jochen Ohnmacht ◽  
Yujie Yang ◽  
Gianna W. Maurer ◽  
Antón Barreiro-Iglesias ◽  
Themistoklis M. Tsarouchas ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Genetic Ablation ◽  
Spinal Motor Neurons ◽  
Larval Zebrafish ◽  
Spinal Motor

scholarly journals Central and peripheral innervation patterns of defined axial motor units in larval zebrafish

2019 ◽  
Author(s):  
Saul Bello-Rojas ◽  
Ana E. Istrate ◽  
Sandeep Kishore ◽  
David L. McLean
Keyword(s):  
Motor Neurons ◽  
Muscle Fibers ◽  
Motor Units ◽  
Spinal Motor Neurons ◽  
Larval Zebrafish ◽  
Spinal Motor ◽  
Axon Collaterals ◽  
Peripheral Innervation ◽  
Innervation Patterns ◽  
Fast Twitch

AbstractSpinal motor neurons and the peripheral muscle fibers they innervate form discrete motor units that execute movements of varying force and speed. Subsets of spinal motor neurons also exhibit axon collaterals that influence motor output centrally. Here, we have used in vivo imaging to anatomically characterize the central and peripheral innervation patterns of axial motor units in larval zebrafish. Using early born ‘primary’ motor neurons and their division of epaxial and hypaxial muscle into four distinct quadrants as a reference, we define three distinct types of later born ‘secondary’ motor units. The largest are ‘m-type’ units, which innervate deeper fast-twitch muscle fibers via medial nerves. Next in size are ‘ms-type’ secondaries, which innervate superficial fast-twitch and slow fibers via medial and septal nerves, followed by ‘s-type’ units, which exclusively innervate superficial slow muscle fibers via septal nerves. All types of secondaries innervate up to four axial quadrants. Central axon collaterals are found in subsets of primaries based on soma position and predominantly in secondary fast-twitch units (m, ms) with increasing likelihood based on number of quadrants innervated. Collaterals are labeled by synaptophysin-tagged fluorescent proteins, but not PSD95, consistent with their output function. Also, PSD95 dendrite labeling reveals that larger motor units receive more excitatory synaptic input. Collaterals are largely restricted to the neuropil, however perisomatic connections are observed between motor units. These observations suggest that recurrent interactions are dominated by motor neurons recruited during stronger movements and set the stage for functional investigations of recurrent motor circuitry in larval zebrafish.

scholarly journals V3 Interneurons Regulate Locomotor Vigor by Recruitment of Spinal Motor Neurons During Fictive Swimming in Larval Zebrafish

2021 ◽  
Author(s):  
Timothy D. Wiggin ◽  
Jacob E. Montgomery ◽  
Amanda J. Brunick ◽  
Jack H. Peck ◽  
Mark A. Masino
Keyword(s):  
Motor Control ◽  
Motor Neurons ◽  
Neuronal Population ◽  
Fine Motor ◽  
Spinal Interneurons ◽  
Spinal Motor Neurons ◽  
Larval Zebrafish ◽  
Spinal Motor ◽  
Spinal Network

ABSTRACTSurvival for vertebrate animals is dependent on the ability to successfully find food, locate a mate, and avoid predation. Each of these behaviors requires fine motor control, which is set by a combination of kinematic properties. For example, the frequency and amplitude (vigor; strength) of motor output combine to determine features of locomotion such as distance traveled and speed. Although there is a good understanding of how different populations of excitatory spinal interneurons establish locomotor frequency, there is not a mechanistic understanding for how locomotor vigor is established. Recent evidence indicates that locomotor vigor is regulated in part by subsets of identified excitatory spinal interneurons (INs), such as the V2a neuronal population in adult zebrafish. Here we provide evidence that the majority of V3 interneurons (V3-INs), which are a developmentally and genetically defined population of ventromedial glutamatergic spinal neurons, are active during fictive swimming. Further, that targeted ablation of V3-INs reduces the proportion of active MNs during fictive swimming, but ablation does not affect the locomotor frequencies produced. These data are consistent with a role of V3-INs in providing excitatory drive to spinal motor neurons during swimming in larval zebrafish, which suggests that locomotor vigor (but not locomotor frequency) may be regulated, in part, by V3-INs.SIGNIFICANCE STATEMENTCurrently, there is a fundamental lack of knowledge about the cellular and spinal network properties that produce locomotor vigor in vertebrates. Here we show, directly for the first time, that V3 interneurons in zebrafish larvae are active duringin vivofictive locomotion, and that targeted ablation of the spinal V3 interneuron population reduces the probability of motoneuron firing during fictive swimming. In contrast to V2a interneurons, ablation of V3 interneurons does not affect locomotor frequency, the fictive neural correlate of speed, which clarifies their role in motor control rather than rhythm generation. Thus, we propose that the V3 interneuron subpopulation is a source of excitation in the vertebrate locomotor neural circuitry that regulates locomotor vigor independently of speed.

scholarly journals Translatomic analysis of regenerating and degenerating spinal motor neurons in injury and ALS

iScience ◽  
2021 ◽  
pp. 102700
Author(s):  
Jennifer L. Shadrach ◽  
Wesley M. Stansberry ◽  
Allison M. Milen ◽  
Rachel E. Ives ◽  
Elizabeth A. Fogarty ◽  
...  
Keyword(s):  
Motor Neurons ◽  
Spinal Motor Neurons ◽  
Spinal Motor

A new method of isolating spinal motor neurons from fetal mouse

2017 ◽  
Vol 288 ◽  
pp. 57-61 ◽  
Author(s):  
Weifang Wang ◽  
Bao Qi ◽  
Hui Lv ◽  
Fei Wu ◽  
Lulu Liu ◽  
...  
Keyword(s):  
Motor Neurons ◽  
New Method ◽  
Fetal Mouse ◽  
Spinal Motor Neurons ◽  
Spinal Motor
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