The Quadrupedal Nature of Human Bipedal Locomotion

Zehr, E. Paul; Hundza, Sandra R.; Vasudevan, Erin

doi:10.1097/jes.0b013e31819c2ed6

Cited by 103 publications

(93 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If we extend the current study to bipedal human locomotion, the findings tend to support the hypothesis that upper limb swing during walking is, in some part, neural in origin Zehr et al 2009). As previously stated, it is thought that arm swing during locomotion is governed by CPGs as hypothesized for lower limb motion.…”

Section: :1 Limb Frequency Relationshipmentioning

confidence: 65%

“…The same seems to be true also for unperturbed hand-and-foot crawling in healthy (Sparrow and Newell 1994;Getchell et al 2001;Patrick et al 2009) and pathological (Tan 2010) adults. This coupling presumably reflects both biomechanical and neural linkages between cervical and lumbosacral central patterns generators (CPGs) that control the upper and lower limbs, respectively Ivanenko et al 2005;Zehr et al 2009). These CPGs have been documented more thoroughly in quadrupedal mammals (Orlovsky et al 1999;Falgairolle et al 2006).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Coupling of upper and lower limb pattern generators during human crawling at different arm/leg speed combinations

et al. 2012

View full text Add to dashboard Cite

show abstract

Section: :1 Limb Frequency Relationshipmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Coupling of upper and lower limb pattern generators during human crawling at different arm/leg speed combinations

et al. 2012

View full text Add to dashboard Cite

show abstract

“…There is evidence that rhythmic movements in humans are also produced in part by spinal CPGs (Capaday et al 1999;Zehr and Stein, 1999;Carroll et al 2006;Zehr et al 2009). A great deal of this research comes from indirect measures of corticospinal tract excitability, which is one of the major descending pathways of the central nervous system (CNS) responsible for voluntary control of movement.…”

Section: -2mentioning

confidence: 99%

“…The essential pattern of alternating activation of functional antagonists has been shown to originate in spinally mediated networks of cells known as central pattern generators (CPGs) (Grillner, 1981;Jordan, 1998). Indirect evidence suggests that rhythmic motor outputs in humans, such as walking, running, and swimming, are also driven by spinally mediated CPGs (Capaday et al 1999;Zehr & Stein, 1999;Carroll et al 2006;Zehr et al 2009). However, unlike our quadruped counterparts, supraspinal input is required during CPG-mediated motor outputs (Petersen et al 2001;Sidhu et al 2012;Forman et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Differences in corticospinal excitability to the biceps brachii between arm cycling and tonic contraction are not evident at the immediate onset of movement

et al. 2016

View full text Add to dashboard Cite

With the use of indirect stimulation techniques, it is possible to examine the basic, underlying mechanisms involved with the neuronal control of voluntary motor outputs in humans. By developing a better understanding of how the central nervous system functions during these outputs, we allow for the possibility of improving current rehabilitative and therapeutic strategies for people with neurological injuries and/or diseases. Recently, this type of work has demonstrated that corticospinal excitability is not task-dependent prior to the initiation of a motor output. However, substantial evidence has shown that corticospinal excitability is task-dependent during motor outputs. Considering these two findings, it is highly plausible that a transition occurs in corticospinal excitability from task-independent to task-dependent as movement progresses from rest to steady-state. The timeline of this transition is poorly understood.Therefore, the purpose of this study was examine the possible task-dependent transition in corticospinal excitability from rest to steady-state arm cycling.iii ACKNOWLEDGEMENTS

show abstract

“…The N-methyl-D-aspartate (NMDA) lesions (1) of the thoracic region between the two hemisections may be effective in stopping locomotion by removing spontaneous propriospinal plasticity rather than by blocking newly developed voluntary control of the locomotor system. Forelimb movement observed in these experiments likely contributed substantially to propriospinal signals that help drive locomotor activity in the hindlimbs (13). Videos in (1) suggest that the rats learned to flail their forelimbs as part of the strategy to attain forward progression to the food reward.…”

mentioning

confidence: 99%

Comment on “Restoring Voluntary Control of Locomotion After Paralyzing Spinal Cord Injury”

Sławińska

Rossignol

Bennett

et al. 2012

Science

View full text Add to dashboard Cite

Van den Brand et al. (Reports, 1 June 2012, p. 1182 claim to have restored voluntary control of locomotion after paralyzing spinal cord injury. They have not considered recent findings that their upright posture paradigm contributes to locomotor capability after such injuries. We propose that postural adjustments that activate the locomotor central pattern generator in the upright posture, rather than direct voluntary control of locomotion, account for their results.V an den Brand et al. claimed to have restored voluntary control of hindlimb locomotion after paralyzing spinal cord injury using an electrochemical neuroprosthesis combined with overground locomotor training in adult rats (1). They used epidural electrical stimulation together with systemically applied drugs and bipedal locomotor training in a robotic postural interface to force rats to walk toward a food reward. Given the impact of such claims for paraplegic patients around the world, it is important to critically examine the evidence provided. In a recent publication, Sławińska and others (2) clearly showed that the upright bipedal posture alone provides sensory feedback that promotes coordinated hindlimb locomotion in the absence of training, drug application, or supraspinal influence. We propose that the bipedal training procedure used by van den Brand et al.(1) initiated locomotion due to forward shifts in posture, thus engaging powerful feedback from load receptors of the hindlimbs that potently facilitates locomotor activity (2, 3). The videos [supplementary materials for (1)] show that the rats move their forelimbs, head, and trunk, thus shifting the center of mass forward. The net effect is an increased loading of the hindlimbs that per se could lead to spinal stepping, especially in the upright posture. Injections of potent excitatory drugs combined with lumbosacral electrical stimulation, as used in their paradigm, likely increases the responsiveness of the spinal locomotor central pattern generator (CPG) to load-bearing inputs. As their figure 4 shows, the onset of overground locomotion is accompanied by an increase in the ground reaction force (GRF), thus facilitating locomotor activity without having to engage direct voluntary control of the locomotor CPG. We propose that the training paradigm resulted in a strategy that shifted the center of mass forward so that the afferent feedback associated with the upright posture, together with the resultant hip extension, engaged the spinal CPG for locomotion and propelled the animal toward the food reward. This interpretation does not require that the brain regain "supraspinal control over the electrochemically enabled lumbosacral circuits," as the authors propose [supplementary materials for (1)].If the training is effective in restoring voluntary locomotion, and this is not because the animals are in the upright posture as we propose, then the rats should display marked recovery of overground quadrupedal locomotion, the normal position for progression in rodents. However, a description of t...

show abstract

The Quadrupedal Nature of Human Bipedal Locomotion

Cited by 103 publications

References 32 publications

Coupling of upper and lower limb pattern generators during human crawling at different arm/leg speed combinations

Coupling of upper and lower limb pattern generators during human crawling at different arm/leg speed combinations

Differences in corticospinal excitability to the biceps brachii between arm cycling and tonic contraction are not evident at the immediate onset of movement

Comment on “Restoring Voluntary Control of Locomotion After Paralyzing Spinal Cord Injury”

Contact Info

Product

Resources

About