Functional Recovery of a Locomotor Network after Injury: Plasticity beyond the Central Nervous System
| Autor: | Anthony W. Bigelow, Karen A. Mesce, Joshua G. Puhl, Mara C. P. Rue |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
animal structures
Dopamine Central nervous system Biology Hirudo medicinalis homeostatic plasticity Lesion 03 medical and health sciences Bursting 0302 clinical medicine Homeostatic plasticity medicine Animals 030304 developmental biology Motor Neurons 0303 health sciences Neuronal Plasticity urogenital system General Neuroscience fungi Central pattern generator General Medicine Recovery of Function New Research Proprioception spinal cord injury Ganglion Ganglia Invertebrate locomotion medicine.anatomical_structure Peripheral nervous system CPG crawling 8.1 Central Pattern Generators Sensory and Motor Systems Neuron medicine.symptom Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | eNeuro |
| ISSN: | 2373-2822 |
| Popis: | Many animals depend on descending information from the brain for the initiation and proper execution of locomotion. Interestingly, after injury and the loss of such inputs, locomotor function can sometimes be regained without the regrowth of central connections. In the medicinal leech,Hirudo verbana, we have shown that crawling reemerges after removal of descending inputs. Here, we studied the mechanisms underlying this return of locomotion by asking if central pattern generators (CPGs) in crawl-recovered leeches are sufficient to produce crawl-specific intersegmental coordination. From recovered animals, we treated isolated chains of ganglia with dopamine to activate the crawl CPGs (one crawl CPG per ganglion) and observed fictive crawl-like bursting in the dorsal-longitudinal-excitor motoneuron (DE-3), an established crawl-monitor neuron. However, these preparations did not exhibit crawl-specific coordination across the CPGs. Although the crawl CPGs always generated bidirectional activation of adjacent CPGs, we never observed crawl-appropriate intersegmental phase delays. Because central circuits alone were unable to organize crawl-specific coordination, we tested the coordinating role of the peripheral nervous system. In transected leeches normally destined for recovery, we removed afferent information to the anterior-most (lead) ganglion located below the nerve-cord transection site. In these dually treated animals, overt crawling was greatly delayed or prevented. After filling the peripheral nerves with Neurobiotin tracer distal to the nerve-root lesion, we found a perfect correlation between regrowth of peripheral neuronal fibers and crawl recovery. Our study establishes that during recovery after injury, crawl-specific intersegmental coordination switches to a new dependence on afferent information. |
| Databáze: | OpenAIRE |
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