https://epublications.marquette.edu/cgi/viewcontent.cgi?article=1048&context=phys_therapy_fac

EEG during pedaling: evidence for cortical control of locomotor tasks.

We have previously reported that rehabilitative reaching training initiated 4 days following an incomplete cervical spinal cord injury (SCI) in adult rats promotes plasticity and task-specific recovery. This training, however, also resulted in impairments in an untrained task. Here we examined whether delaying the rehabilitative training following cervical SCI is still effective in promoting task-specific recovery, but circumvents impairments in an untrained task, comparable to what has been reported in stroke models. Therefore, reaching training for a period of 6 weeks was initiated at Day 12 following a cervical dorso-lateral quadrant lesion. Thereupon the rats' ability to reach and to walk on a horizontal ladder (i.e. the untrained task) was assessed, and 8 weeks post-injury cortical map changes were investigated through microstimulation. Further, we examined changes in phospho protein kinase A (pPKA) levels following an immediate and a delayed onset of reaching training in rats with cervical SCI. We found that delayed rehabilitative training was comparably effective as immediate training in promoting task-specific recovery and sprouting of injured axons. Importantly, delayed training did not impair the performance on horizontal ladder walking. Strikingly, only delayed reaching training restored cortical PKA levels that had dropped significantly over 2 weeks post-injury. Additionally, delayed training did not influence cortical map changes following injury, but decreased white matter damage. In conclusion, our results show that a short delay in the onset of training in a forelimb task significantly alters our outcome measures, which should be considered in future rehabilitative approaches.

Advantages of delaying the onset of rehabilitative reaching training in rats with incomplete spinal cord injury.

Background. Reliable outcome measures are essential for preclinical modeling of spinal cord injury (SCI) in primates. Measures need to be sensitive to both increases and decreases in function in order to demonstrate potential positive or negative effects of therapeutics. Objectives. To develop behavioral tests and analyses to assess recovery of function after SCI in the nonhuman primate. Methods. In all, 24 male rhesus macaques were subjected to complete C7 lateral hemisection. The authors scored recovery of function in an open field and during hand tasks in a restraining chair. In addition, EMG analyses were performed in the open field, during hand tasks, and while animals walked on a treadmill. Both control and treated monkeys that received candidate therapeutics were included in this report to determine whether the behavioral assays were capable of detecting changes in function over a wide range of outcomes. Results. The behavioral assays are shown to be sensitive to detecting a wide range of motor fun...

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Methods for functional assessment after C7 spinal cord hemisection in the rhesus monkey.

After an incomplete spinal cord injury (SCI), we know that plastic reorganization occurs in supraspinal structures with residual descending tracts. However, our knowledge about spinal plasticity is rather limited. Our recent studies point to changes within the spinal cord below the lesion. After a lateral left hemisection (T10), cats recovered stepping with both hindlimbs within 3 weeks. After a complete section (T13) in these cats, bilateral stepping was seen on the next day, a skill usually acquired after several weeks of treadmill training. This indicates that durable plastic changes occurred below the lesion. However, because sensory feedback entrains the stepping rhythm, it is difficult to reveal central pattern generator (CPG) adaptation. Here, we investigated whether lumbar segments of cats with a chronic hemisection were able to generate fictive locomotion—that is, without phasic sensory feedback as monitored by five muscle nerves in each hindlimb. With a chronic left hemisection, the number of muscle nerves displaying locomotor bursts was larger on the left than on the right. In addition, transmission of cutaneous reflexes was relatively facilitated on the left. Later during the acute experiment, a complete spinalization (T13) was performed and clonidine was injected to induce rhythmic activities. There were still more muscle nerves displaying locomotor bursts on the left. The results demonstrate that spinal networks were indeed modified after a hemisection with a clear asymmetry between left and right in the capacity to generate locomotion. Plastic changes in CPG and reflex transmission below the lesion are thus involved in the stepping recovery after an incomplete SCI.

https://www.jneurosci.org/content/jneuro/35/25/9446.full.pdf

Plastic Changes in Lumbar Locomotor Networks after a Partial Spinal Cord Injury in Cats

Sprouting of axonal collaterals after spinal cord injury is prevented by delayed axonal degeneration

Green tea extract mediated biogenic synthesis of gold nanoparticles with potent anti-proliferative effect against PC-3 human prostate cancer cells

Analysis of the recovery of gait after spinal cord injury has been widely demonstrated in rat and cat models using different behavioral tests and scoring systems. The present investigation was aimed to quantitatively analyze the degree of functional recovery in bipedal locomotion of bonnet macaques after inflicting spinal cord hemisection lesion. To measure the degree of locomotor recovery, we recorded four gait variables, viz., tip of opposite foot (TOF), print length (PL), toe spread (TS), and intermediary toes (IT) using a footprint analyzing technique. Monkeys were trained preoperatively to perform the monopedal hop or bipedal locomotion on runways. Footprints of trained monkeys were recorded using the nontoxic ink and white paper before and after surgery. Surgical hemisection was induced unilaterally in the right side of spinal cord at T12-L1 level of trained monkeys. In hemiplegic monkeys, initially there was a substantial decrease in TOF and PL variables of the paretic limb, which then gradually increased for longer duration and reached the near presurgical values by the 7th and 5th postoperative month, respectively. In contrast to TOF and PL, the recovery of TS and IT variables was quicker, which dramatically increased at first and then slowly recovered to levels not significantly different from the corresponding preoperative values by the 4th postoperative month. The nonparetic limb has also showed mild alterations in all footprint variables but reached the normal values much faster compared to the paretic limb. The alterations in footprint variables of hemiplegic monkeys were examined for a postoperative period of up to 1 year. The findings of this study suggest that the mechanisms underlying locomotor recovery of lesioned macaques may be correlated to the mature function of spinal pattern generator for locomotion under the impact of residual descending and afferent connections. Further, this study also indicates the functional contribution of progressive strengthening of undamaged nerve fibers through a collateral sprouts/synaptic plasticity formed in partially lesioned cord of macaques. Synapse 62:432–447, 2008. © 2008 Wiley-Liss, Inc.

R. Suresh Babu

Papers

Green tea extract mediated biogenic synthesis of gold nanoparticles with potent anti-proliferative effect against PC-3 human prostate cancer cells

Recovery of bipedal locomotion in bonnet macaques after spinal cord injury: Footprint analysis