scholarly journals A novel optic flow pattern speeds split-belt locomotor adaptation

2014 ◽  
Vol 111 (5) ◽  
pp. 969-976 ◽  
Author(s):  
James M. Finley ◽  
Matthew A. Statton ◽  
Amy J. Bastian
Keyword(s):  
Flow Pattern ◽  
Optic Flow ◽  
Learning Rate ◽  
Locomotor Training ◽  
Belt Speed ◽  
Locomotor Adaptation ◽  
Walking Pattern ◽  
Foot Strike ◽  
Pattern Speeds ◽  
Congruent Group

Visual input provides vital information for helping us modify our walking pattern. For example, artificial optic flow can drive changes in step length during locomotion and may also be useful for augmenting locomotor training for individuals with gait asymmetries. Here we asked whether optic flow could modify the acquisition of a symmetric walking pattern during split-belt treadmill adaptation. Participants walked on a split-belt treadmill while watching a virtual scene that produced artificial optic flow. For the Stance Congruent group, the scene moved at the slow belt speed at foot strike on the slow belt and then moved at the fast belt speed at foot strike on the fast belt. This approximates what participants would see if they moved over ground with the same walking pattern. For the Stance Incongruent group, the scene moved fast during slow stance and vice versa. In this case, flow speed does not match what the foot is experiencing, but predicts the belt speed for the next foot strike. Results showed that the Stance Incongruent group learned more quickly than the Stance Congruent group even though each group learned the same amount during adaptation. The increase in learning rate was primarily driven by changes in spatial control of each limb, rather than temporal control. Interestingly, when this alternating optic flow pattern was presented alone, no adaptation occurred. Our results demonstrate that an unnatural pattern of optic flow, one that predicts the belt speed on the next foot strike, can be used to enhance learning rate during split-belt locomotor adaptation.

A Model of Position-Invariant, Optic Flow Pattern-Selective Cells

1997 ◽  
pp. 171-176 ◽  
Author(s):  
Robert I. Pitts ◽  
V. Sundareswaran ◽  
Lucia M. Vaina
Keyword(s):  
Flow Pattern ◽  
Optic Flow

scholarly journals Pain Induced during Both the Acquisition and Retention Phases of Locomotor Adaptation Does Not Interfere with Improvements in Motor Performance

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jason Bouffard ◽  
Laurent J. Bouyer ◽  
Jean-Sébastien Roy ◽  
Catherine Mercier
Keyword(s):  
Motor Performance ◽  
Temporal Distribution ◽  
Control Group ◽  
Electromyographic Activity ◽  
Locomotor Training ◽  
Locomotor Adaptation ◽  
Movement Error ◽  
Motor Strategy ◽  
Motor Strategies ◽  
Healthy Participants

Cutaneous pain experienced during locomotor training was previously reported to interfere with retention assessed in pain-free conditions. To determine whether this interference reflects consolidation deficits or a difficulty to transfer motor skills acquired in the presence of pain to a pain-free context, this study evaluated the effect of pain induced during both the acquisition and retention phases of locomotor learning. Healthy participants performed a locomotor adaptation task (robotized orthosis perturbing ankle movements during swing) on two consecutive days. Capsaicin cream was applied around participants’ ankle on both days for the Pain group, while the Control group was always pain-free. Changes in movement errors caused by the perturbation were measured to assess global motor performance; temporal distribution of errors and electromyographic activity were used to characterize motor strategies. Pain did not interfere with global performance during the acquisition or the retention phases but was associated with a shift in movement error center of gravity to later in the swing phase, suggesting a reduction in anticipatory strategy. Therefore, previously reported retention deficits could be explained by contextual changes between acquisition and retention tests. This difficulty in transferring skills from one context to another could be due to pain-related changes in motor strategy.

scholarly journals Modulating locomotor adaptation with cerebellar stimulation

2012 ◽  
Vol 107 (11) ◽  
pp. 2950-2957 ◽  
Author(s):  
Gowri Jayaram ◽  
Byron Tang ◽  
Rani Pallegadda ◽  
Erin V. L. Vasudevan ◽  
Pablo Celnik ◽  
...  
Keyword(s):  
Neural Circuits ◽  
Critical Role ◽  
Locomotor Training ◽  
Control Mechanisms ◽  
Adaptive Process ◽  
Locomotor Adaptation ◽  
Neurological Patients ◽  
Cerebellar Tdcs ◽  
Stimulation Of ◽  
Cerebellar Stimulation

Human locomotor adaptation is necessary to maintain flexibility of walking. Several lines of research suggest that the cerebellum plays a critical role in motor adaptation. In this study we investigated the effects of noninvasive stimulation of the cerebellum to enhance locomotor adaptation. We found that anodal cerebellar transcranial direct current stimulation (tDCS) applied during adaptation expedited the adaptive process while cathodal cerebellar tDCS slowed it down, without affecting the rate of de-adaptation of the new locomotor pattern. Interestingly, cerebellar tDCS affected the adaptation rate of spatial but not temporal elements of walking. It may be that spatial and temporal control mechanisms are accessible through different neural circuits. Our results suggest that tDCS could be used as a tool to modulate locomotor training in neurological patients with gait impairments.

scholarly journals Development of radial optic flow pattern sensitivity at different speeds

2015 ◽  
Vol 110 ◽  
pp. 68-75 ◽  
Author(s):  
Mahesh Raj Joshi ◽  
Helle K. Falkenberg
Keyword(s):  
Flow Pattern ◽  
Optic Flow ◽  
Pattern Sensitivity

scholarly journals Blocking trial-by-trial error correction does not interfere with motor learning in human walking

2016 ◽  
Vol 115 (5) ◽  
pp. 2341-2348 ◽  
Author(s):  
Andrew W. Long ◽  
Ryan T. Roemmich ◽  
Amy J. Bastian
Keyword(s):  
Error Correction ◽  
Motor Pattern ◽  
Step Length ◽  
The Other ◽  
Human Walking ◽  
Not Given ◽  
Foot Placement ◽  
Locomotor Adaptation ◽  
Walking Pattern ◽  
Environmental Demands

Movements can be learned implicitly in response to new environmental demands or explicitly through instruction and strategy. The former is often studied in an environment that perturbs movement so that people learn to correct the errors and store a new motor pattern. Here, we demonstrate in human walking that implicit learning of foot placement occurs even when an explicit strategy is used to block changes in foot placement during the learning process. We studied people learning a new walking pattern on a split-belt treadmill with and without an explicit strategy through instruction on where to step. When there is no instruction, subjects implicitly learn to place one foot in front of the other to minimize step-length asymmetry during split-belt walking, and the learned pattern is maintained when the belts are returned to the same speed, i.e., postlearning. When instruction is provided, we block expression of the new foot-placement pattern that would otherwise naturally develop from adaptation. Despite this appearance of no learning in foot placement, subjects show similar postlearning effects as those who were not given any instruction. Thus locomotor adaptation is not dependent on a change in action during learning but instead can be driven entirely by an unexpressed internal recalibration of the desired movement.

scholarly journals Optic flow improves adaptability of spatiotemporal characteristics during split-belt locomotor adaptation with tactile stimulation

2015 ◽  
Vol 234 (2) ◽  
pp. 511-522 ◽  
Author(s):  
Diderik Jan A. Eikema ◽  
Jung Hung Chien ◽  
Nicholas Stergiou ◽  
Sara A. Myers ◽  
Melissa M. Scott-Pandorf ◽  
...  
Keyword(s):  
Optic Flow ◽  
Tactile Stimulation ◽  
Locomotor Adaptation ◽  
Spatiotemporal Characteristics

scholarly journals Optic flow serves as a teaching signal for visual-locomotor adaptation

2010 ◽  
Vol 7 (9) ◽  
pp. 152-152
Author(s):  
W. Warren ◽  
H. Bruggeman ◽  
W. Zosh
Keyword(s):  
Optic Flow ◽  
Locomotor Adaptation ◽  
Teaching Signal

scholarly journals Different Error Size During Locomotor Adaptation Affects Transfer to Overground Walking Poststroke

2018 ◽  
Vol 32 (12) ◽  
pp. 1020-1030 ◽  
Author(s):  
Carolina C. Alcântara ◽  
Charalambos C. Charalambous ◽  
Susanne M. Morton ◽  
Thiago L. Russo ◽  
Darcy S. Reisman
Keyword(s):  
Catch Trial ◽  
Step Length ◽  
Similar Amount ◽  
Adaptation Period ◽  
Overground Walking ◽  
Locomotor Adaptation ◽  
Walking Pattern ◽  
Gradual Group ◽  
Adaptation Response ◽  
Group A

Background. Studies in neurologically intact subjects suggest that the gradual presentation of small perturbations (errors) during learning results in better transfer of a newly learned walking pattern to overground walking. Whether the same result would be true after stroke is not known. Objective. To determine whether introducing gradual perturbations, during locomotor learning using a split-belt treadmill influences learning the novel walking pattern or transfer to overground walking poststroke. Methods. Twenty-six chronic stroke survivors participated and completed the following walking testing paradigm: baseline overground walking; baseline treadmill walking; split-belt treadmill/adaptation period (belts moving at different speeds); catch trial (belts at same speed); post overground walking. Subjects were randomly assigned to the Gradual group (gradual changes in treadmill belts speed during adaptation) or the Abrupt group (a single, large, abrupt change during adaptation). Step length asymmetry adaptation response on the treadmill and transfer of learning to overground walking was assessed. Results. Step length asymmetry during the catch trial was the same between groups ( P = .195) confirming that both groups learned a similar amount. The magnitude of transfer to overground walking was greater in the Gradual than in the Abrupt group ( P = .041). Conclusions. The introduction of gradual perturbations (small errors), compared with abrupt (larger errors), during a locomotor adaptation task seems to improve transfer of the newly learned walking pattern to overground walking poststroke. However, given the limited magnitude of transfer, future studies should examine other factors that could impact locomotor learning and transfer poststroke.

scholarly journals Treadmill integrated robot-assisted ankle dorsiflexion training for stroke rehabilitation: A randomized controlled trial

2020 ◽  
Author(s):  
Susan Conroy ◽  
Anindo Roy ◽  
Laurence Magder ◽  
Derek Eversley ◽  
Kate Flores ◽  
...  
Keyword(s):  
Randomized Controlled Trial ◽  
Motor Control ◽  
Controlled Trial ◽  
Ankle Dorsiflexion ◽  
Treadmill Training ◽  
Foot Drop ◽  
Gait Velocity ◽  
Locomotor Training ◽  
Randomized Controlled ◽  
Foot Strike

Abstract Background: Stroke-related ankle dysfunction due to hemiparesis has a profound negative impact on gait biomechanics and walking. Task-oriented treadmill training improves gait velocity but does not lead to restitution of ankle function. Advances in robotic technology have led to the development of an adaptive ankle robot that can be integrated into treadmill walking and provide precisely timed graded assistance consistent with motor learning approaches. The aim of this study was to compare the effectiveness of a 6-week treadmill-integrated adaptive ankle robot (TMR) training to 6-weeks of treadmill training (TM) alone on improved paretic ankle motor control and gait performance. Methods: This was a single-blind (evaluator-blinded) randomized controlled trial. 45 participants received either TMR or TM training 3 times per week for 6 weeks. Primary outcomes were improved peak paretic ankle dorsiflexion (DF) angle at swing, improved DF angle at foot strike (weight acceptance), and increased gait velocity during self-selected over-ground walking. The primary analysis was based on intention-to-treat using a longitudinal regression model. An additional sub-set analysis of subjects with biomechanically defined foot drop was performed. Results: There were no significant post-training ankle dorsiflexion or gait velocity differences between groups. Six-week post-training mean peak paretic DF swing angle was (4.84 ± 6.83; 4.2 ± 6.83 p =0.63) and DF angle at foot strike was (-0.70 ± 6.55; -0.46 ± 5.70 p =0.84) respectively for TMR and TM. Gait velocity gains were similar and TMR had a mean increase of 0.54 m/s ± 0.24 and TM increased 0.56 m/s ±0.32. p =0.48 post-training. Conclusion: Integrating adaptive ankle robotics into task-specific locomotor training was not significantly better than treadmill training alone. Both interventions improved gait velocity. Promising results in ankle motor control were seen in a subset of subjects with biomechanically defined foot drop that warrants further investigation. Keywords: Stroke, hemiparetic gait, ankle robot, locomotor training Clinical trials.gov id: NCT02483676. Registered June 29, 2015, https://clinicaltrials.gov/ct2/show/NCT02483676

The Moving Platform Aftereffect: Limited Generalization of a Locomotor Adaptation

2004 ◽  
Vol 91 (1) ◽  
pp. 92-100 ◽  
Author(s):  
R. F. Reynolds ◽  
A. M. Bronstein
Keyword(s):  
Baseline Period ◽  
Adaptation Period ◽  
Locomotor Adaptation ◽  
Walking Pattern ◽  
After Effect ◽  
Walking Velocity ◽  
Full Knowledge ◽  
Flashing Light ◽  
Moving Platform ◽  
Insight Into

We have recently described a postural after-effect of walking onto a stationary platform previously experienced as moving, which occurs despite full knowledge that the platform will no longer move. This experiment involves an initial baseline period when the platform is kept stationary (BEFORE condition), followed by a brief adaptation period when subjects learn to walk onto the platform moving at 1.2 m/s (MOVING condition). Subjects are clearly warned that the platform will no longer move and asked to walk onto it again (AFTER condition). Despite the warning, they walk toward the platform with a velocity greater than that observed during the BEFORE condition, and a large forward sway of the trunk is observed once they have landed on the platform. This aftereffect, which disappears within three trials, represents dissociation of knowledge and action. In the current set of experiments, to gain further insight into this phenomenon, we have manipulated three variables, the context, location, and method of the walking task, between the MOVING and AFTER conditions, to determine how far the adaptation will generalize. It was found that when the gait initiation cue was changed from beeps to a flashing light, or vice versa, there was no difference in the magnitude of the aftereffect, either in terms of walking velocity or forward sway of the trunk. Changing the leg with which gait was initiated, however, reduced sway magnitude by approximately 50%. When subjects changed from forward walking to backward walking, the aftereffect was abolished. Similarly, walking in a location other than the mobile platform did not produce any aftereffect. However, in these latter two experiments, the aftereffect reappeared when subjects reverted to the walking pattern used during the MOVING condition. Hence, these results show that a change in abstract context had no influence, whereas any deviation from the way and location in which the moving platform task was originally performed profoundly reduced the size of the aftereffect. Although the moving platform aftereffect is an example of inappropriate generalization by the motor system across time, these results show that this generalization is highly limited to the method and location in which the original adaptation took place.

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