Functional plasticity in the respiratory drive to thoracic motoneurons in the segment above a chronic lateral spinal cord lesion
| Autor: | Natalya P. Anissimova, Peter A. Kirkwood, Tim W. Ford, C. F. Meehan |
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| Rok vydání: | 2016 |
| Předmět: |
Male
0301 basic medicine Physiology medicine.medical_treatment Lesion 03 medical and health sciences 0302 clinical medicine Neural Pathways Neuroplasticity medicine Animals Spinal cord injury Motor Neurons Medulla Oblongata Neuronal Plasticity business.industry Respiration General Neuroscience Laminectomy Neurophysiology medicine.disease Spinal cord 030104 developmental biology medicine.anatomical_structure Spinal Cord nervous system Control of respiration Cats Medulla oblongata Female medicine.symptom Control of Movement business Neuroscience 030217 neurology & neurosurgery Spinal cord injury Thoracic motoneurons Respiratory drive Plasticity |
| Zdroj: | Journal of Neurophysiology. 115:554-567 |
| ISSN: | 1522-1598 0022-3077 |
| DOI: | 10.1152/jn.00614.2015 |
| Popis: | A previous neurophysiological investigation demonstrated an increase in functional projections of expiratory bulbospinal neurons (EBSNs) in the segment above a chronic lateral thoracic spinal cord lesion that severed their axons. We have now investigated how this plasticity might be manifested in thoracic motoneurons by measuring their respiratory drive and the connections to them from individual EBSNs. In anesthetized cats, simultaneous recordings were made intracellularly from motoneurons in the segment above a left-side chronic (16 wk) lesion of the spinal cord in the rostral part of T8, T9, or T10 and extracellularly from EBSNs in the right caudal medulla, antidromically excited from just above the lesion but not from below. Spike-triggered averaging was used to measure the connections between pairs of EBSNs and motoneurons. Connections were found to have a very similar distribution to normal and were, if anything (nonsignificantly), weaker than normal, being present for 42/158 pairs, vs. 55/154 pairs in controls. The expiratory drive in expiratory motoneurons appeared stronger than in controls but again not significantly so. Thus we conclude that new connections made by the EBSNs following these lesions were made to neurons other than α-motoneurons. However, a previously unidentified form of functional plasticity was seen in that there was a significant increase in the excitation of motoneurons during postinspiration, being manifest either in increased incidence of expiratory decrementing respiratory drive potentials or in an increased amplitude of the postinspiratory depolarizing phase in inspiratory motoneurons. We suggest that this component arose from spinal cord interneurons. |
| Databáze: | OpenAIRE |
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