45 46 In animals, the recovery of motoneuron excitability in the months following a complete spinal cord 47 injury is mediated, in part, by increases in constitutive serotonin (5HT2) and noradrenaline (α1) 48 receptor activity, which facilitates the reactivation of calcium-mediated persistent inward currents 49 (CaPICs) without the ligands serotonin and noradrenaline below the injury. Here, we ...

Gardiner, P., Y. Dai, and C. J. Heckman. Effects of exercise training on -motoneurons.JApplPhysiol101:1228–1236,2006.doi:10.1152/japplphysiol.00482.2006.— Evidence is presented that one locus of adaptation in the “neural adaptations to training” is at the level of the -motoneurons. With increased voluntary activity, these neurons show evidence of dendrite restructuring, increased protein synthe...

Martin PG, Hudson AL, Gandevia SC, Taylor JL. Reproducible measurement of human motoneuron excitability with magnetic stimulation of the corticospinal tract. J Neurophysiol 102: 606–613, 2009. First published April 29, 2009; doi:10.1152/jn.91348.2008. It is difficult to test responses of human motoneurons in a controlled way or to make longitudinal assessments of adaptive changes at the motoneu...

The neuromuscular adaptations in response to muscle stretch training have not been clearly described. In the present study, changes in muscle (at fascicular and whole muscle levels) and tendon mechanics, muscle activity, and spinal motoneuron excitability were examined during standardized plantar flexor stretches after 3 wk of twice daily stretch training (4 × 30 s). No changes were observed in...

The possible presence of pathological changes in cholinergic synaptic inputs [cholinergic boutons (C-boutons)] is a contentious topic within the ALS field. Conflicting data reported on this issue makes it difficult to assess the roles of these synaptic inputs in ALS. Our objective was to determine whether the reported changes are truly statistically and biologically significant and why replicat...

Selective serotonin reuptake inhibitors (SSRIs) and other antidepressants are often prescribed to amyotrophic lateral sclerosis (ALS) patients; however, the impact of these prescriptions on ALS disease progression has not been systematically tested. To determine whether SSRIs impact disease progression, fluoxetine (Prozac, 5 or 10 mg/kg) was administered to mutant superoxide dismutase 1 (SOD1) ...

Gardiner, P., Y. Dai, and C. J. Heckman. Effects of exercise training on -motoneurons.JApplPhysiol101:1228–1236,2006.doi:10.1152/japplphysiol.00482.2006.— Evidence is presented that one locus of adaptation in the “neural adaptations to training” is at the level of the -motoneurons. With increased voluntary activity, these neurons show evidence of dendrite restructuring, increased protein synthe...

We compared the effect of viral administration of brain-derived neurotrophic factor (BDNF) or neurotrophin 3 (NT-3) on locomotor recovery in adult rats with complete thoracic (T10) spinal cord transection injuries, in order to determine the effect of chronic neurotrophin expression on spinal plasticity. At the time of injury, BDNF, NT-3 or green fluorescent protein (GFP) (control) was delivered...

Combined V-wave and Hoffmann (H) reflex measurements were performed during maximal muscle contraction to examine the neural adaptation mechanisms induced by resistance training. The H-reflex can be used to assess the excitability of spinal alpha-motoneurons, while also reflecting transmission efficiency (i.e., presynaptic inhibition) in Ia afferent synapses. Furthermore, the V-wave reflects the...

An assemblage of individual motoneurons constituting a synthetic motoneuron pool has been studied from the standpoint of relating monosynaptic reflex responses to frequency of afferent stimulation. Intensity of low frequency depression is not a simple function of transmitter potentiality. As frequency of stimulation increases from 3 per minute to 10 per second, low frequency depression increase...