Bibliographic record
Abstract
Locomotot training has gained in popuiarity and is more and more integrated in tehabilitative strategies to enhance stepping recovery in spinal cord injured (SOI) individuals.This strategy is ditectly inspired from several decades of work performed in the Iaboratory taking advantage cf a spinal cat model in which reflex and locomotor pathways are exhaustively described.Compietely isclated from supraspinai influences, the spinal cord has the capacity to recover stepping movements when given repetitïve and appropriate sensory feedback related to step-training on a treadmill.However, the underlying mechanisms for recuperating the appropriate motor patterns are stiil poorly understood and are the scope of this study.Project I.It is generally assumed that plasticity in spinal locomotor circuits is responsible for the stepping recovery.However, the repetitive sensory stimulation related to step-training couid also modify transmission in reflex pathways, which are aise known to contribute significantly to the level cf muscle activity during stepping.In this project, transmission in reflex pathways was evaluated by measuring responses evoked by a stimulation cf a cutaneous or muscle nerve cf the hindpaw and recorded intracellularly in motoneurons from extensor and flexor muscles involved in ankle, knee and hip joint movements during an acute experiment in decerebrate cats.Possible modifications in reflex transmission were determined by the statistical comparison 0f responses between 2 groups cf spinal cats (complete transection at T13), but only one was assigned te a step-training regimen.Results showed that the synaptic transmission in both group I muscle reflex pathways from extensors and cutaneous pathways were modified following one month cf step-training.The monosynaptic excitation was decreased atter step-training and a normal pattern of modulation was recovered during locomotion.Moreover, group lb inhibition and polysynaptic group I excitation cf extensors were respectively decreased and increased after step-training and clonidine injection, a noradrenergic agonist useful for central pattern generation.t was further observed that plasticity in cutaneous pathways was highly specific: only certain pathways wete modulated (mostiy depressed).Transmission cf cutaneous input originating from the sole cf the foot was particularly modified.Overall, step-training is suggested te both decrease the hyperexcitability observed in reflex pathways after SCI and te facilitate the recruitment cf antigravity muscles te assist recovery and weight bearing.vi Project II.There is now strong evidence that spinal circuits can be affected by activity dependent biochemical processes that influence its ability to recover, perform and maintain an adequate Iocomotor pattern.Investigations have recentiy been oriented towatd molecules involved in LTP to determine if similar mechanisms are both implicated in hippocampal learning and spinal motor learning.Given the preponderant effect of ERK on synaptic piasticity and function and its role in integrating signais from the ceii surface to transcription factors, ERK appears to be a potentiai candidate for mediating the beneficial effects of step-training and may participate in the synaptic events associated with locomotor recovery aftet SOI.Ptotein expression was compared between 3 groups of cats (intact, SCI, SOI and step-trained) using western biot analysis of homogenates of spinal cord segments.The study focussed on assessing relative levels of ERK and pERK proteins.Resuits showed that ERK activation is up-regulated in a majority of lumbar segments following SCI and is specificaily down-reguiated in L5 by steptraining.These resuits suggest that ERK activation is invoived in long-term plasticity foilowing SOI and that it may be detrimental to iocomotor generation, at Ieast in specific spinal segments.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".