scholarly journals Use of explicit processes during a visually guided locomotor learning task predicts 24-hour retention after stroke

Author(s):  
Margaret A French ◽  
Susanne M. Morton ◽  
Darcy S. Reisman

Implicit and explicit processes can occur within a single locomotor learning task. The combination of these learning processes may impact how individuals acquire/retain the task. Because these learning processes rely on distinct neural pathways, neurologic conditions may selectively impact the processes that occur, thus, impacting learning and retention. Thus, our purpose was to examine the contribution of implicit and explicit processes during a visually guided walking task and characterize the relationship between explicit processes and performance/retention in stroke survivors and age-matched healthy adults. Twenty chronic stroke survivors and twenty healthy adults participated in a 2-day treadmill study. Day 1 included Baseline, Acquisition1, Catch, Acquisition2, and Immediate Retention phases and Day 2 included 24-hour Retention. During acquisition phases, subjects learned to take a longer step with one leg through distorted visual feedback. During Catch and retention phases, visual feedback was removed and subjects were instructed to walk normally (Catch) or how they walked during the acquisition phases (retention). Change in step length from Baseline to Catch represented implicit processes. Change in step length from Catch to the end of Acquisition2 represented explicit processes. A mixed ANOVA found no difference in the type of learning between groups (p=0.74). There was a significant relationship between explicit processes and 24-hour retention in stroke survivors (r=0.47, p=0.04), but not in healthy adults (r=0.34, p=0.15). These results suggest that stroke may not affect the underlying learning mechanisms used during locomotor learning, but that these mechanisms impact how well stroke survivors retain the new walking pattern.

2016 ◽  
Author(s):  
Li-Ann Leow ◽  
Welber Marinovic ◽  
Stephan Riek ◽  
Timothy J Carroll

AbstractThe cerebellum is known to be critically involved in sensorimotor adaptation. Changes in cerebellar function alter behaviour when compensating for sensorimotor perturbations, as shown by non-invasive stimulation of the cerebellum and studies involving patients with cerebellar degeneration. It is known, 24 however, that behavioural responses to sensorimotor perturbations reflect both explicit processes (such as volitional aiming to one side of a target to counteract a rotation of visual feedback) and implicit, error-driven updating of sensorimotor maps. The contribution of the cerebellum to these explicit and implicit processes remains unclear. Here, we examined the role of the cerebellum in sensorimotor adaptation to a 30° rotation of visual feedback of hand position during target-reaching, when the capacity to use explicit processes was manipulated by controlling movement preparation times. Explicit re-aiming was suppressed in one condition by requiring subjects to initiate their movements within 300ms of target presentation, and permitted in another condition by requiring subjects to wait approximately 1050ms after target presentation before movement initiation. Similar to previous work, applying anodal transcranial direct current stimulation (tDCS; 1.5mA) to the right cerebellum during adaptation resulted in faster compensation for errors imposed by the rotation. After exposure to the rotation, we evaluated implicit remapping in no-feedback trials after providing participants with explicit knowledge that the rotation had been removed. Crucially, movements were more adapted in these no-feedback trials following cerebellar anodal tDCS than after sham stimulation in both long and short preparation groups. This suggests that cerebellar anodal tDCS increased implicit remapping during sensorimotor adaptation irrespective of preparation time constraints. This work shows that the cerebellum is critical in the formation of new visuomotor maps that correct perturbations in sensory feedback, both when explicit processes are suppressed and when allowed during sensorimotor adaptation.


AILA Review ◽  
2010 ◽  
Vol 23 ◽  
pp. 7-29 ◽  
Author(s):  
Karen Roehr

SLA researchers agree that explicit knowledge and learning play an important role in adult L2 development. In the field of cognitive linguistics, it has been proposed that implicit and explicit knowledge differ in terms of their internal category structure and the processing mechanisms that operate on their representation in the human mind. It has been hypothesized that linguistic constructions which are captured easily by metalinguistic descriptions can be learned successfully through explicit processes, resulting in accurate use. However, increased accuracy of use arising from greater reliance on explicit processing may lead to decreased fluency. Taking these hypotheses as a starting point, I present a case study of an adult L2 learner whose development of oral proficiency was tracked over 17 months. Findings indicate that explicit knowledge and learning have benefits as well as limitations. Use of metalinguistic tools was associated with increased accuracy; moreover, there was no obvious trade-off between accuracy and fluency. At the same time, resource-intensive explicit processing may impose too great a cognitive load in certain circumstances, apparently resulting in implicit processes taking over. I conclude that explicit and implicit knowledge and learning should be considered together in order to gain a full understanding of L2 development.


1994 ◽  
Vol 79 (1) ◽  
pp. 163-184 ◽  
Author(s):  
Jill H. Rathus ◽  
Arthur S. Reber ◽  
Louis Manza ◽  
Michael Kushner

Two experiments using a standard artificial grammar paradigm were conducted to examine the role of affective states, specifically anxiety and depression, on implicit learning. The main purpose was to broaden the range of human functioning explored through the application of the robustness principle in the evolutionary framework recently developed by Reber which predicts that cognitive processes which rely upon unconscious, implicit processes should be less affected by affective states than those which rely upon conscious, explicit processes. In Study 1 ( N = 60), high test anxiety was associated with performance deficits in the explicit components of the task; no differences were found in the implicit phases of the task. In Study 2 ( N = 160), varying levels of subclinical depression were unrelated to both implicit and explicit functioning. The contrasting findings of the two studies are discussed in terms of the differential cognitive effects and adaptive implications of these two affective states.


2020 ◽  
Author(s):  
Santiago Muñoz-Moldes ◽  
Axel Cleeremans

Neurofeedback allows humans to self-regulate neural activity in specific brain regions and is considered a promising tool for psychiatric interventions. Recently, methods have been developed to use neurofeedback implicitly, prompting a theoretical debate on the role of awareness in neurofeedback learning. We offer a critical review of the role of awareness in neurofeedback learning, with a special focus on recently developed neurofeedback paradigms. We detail differences in instructions and propose a fine-grained categorization of tasks based on the degree of involvement of explicit and implicit processes. Finally, we review the methods used to measure awareness in neurofeedback and propose new candidate measures. We conclude that explicit processes cannot be eschewed in most current implicit tasks that have explicit goals, and suggest ways in which awareness could be better measured in the future. Investigating awareness during learning will help understand the learning mechanisms underlying neurofeedback learning and will help shape future tasks.


2021 ◽  
Author(s):  
Gefen Dawidowicz ◽  
Yuval Shaine ◽  
Firas Mawase

Acquisition of multiple motor skills without interference is a remarkable ability in sport and daily life. During adaptation to opposing perturbations, a common paradigm to study this ability, each perturbation can be successfully learned when a dynamical contextual cue, such as a follow-through movement, is associated with the direction of the perturbation. It is still unclear, however, to what extent this context-dependent learning engages the cognitive strategy-based explicit process and the implicit process that occurs without conscious awareness. Here, we designed four reaching experiments to untangle the individual contributions of the explicit and implicit components while participants learned opposing visuomotor perturbations, with a second unperturbed follow-through movement that served as a contextual cue. In Exp. 1 we replicated previous adaptation results and showed that follow-through movements also allow learning for opposing visuomotor rotations. For one group of participants in Exp. 2 we isolated strategic explicit learning by inducing a 2-sec time delay between movement and end-point feedback, while for another group we isolated the implicit component using the task-irrelevant error-clamp paradigm, in which participants were firmly instructed to aim their reaches directly to the target. Our data showed that opposing perturbations could be fully learned by explicit strategies; but when strategy was restricted, distinct implicit processes contributed to learning. In Exp.3, we examined whether the learned motor behaviors are influenced by the disparity between the follow-through contexts. We found that the location of follow-through targets had little effect on total learning, yet it led to more instances in which participants failed to learn the task. In Exp. 4, we explored the generalization capability to untrained novel targets. Participants showed near-flat generalization of the implicit and explicit processes to adjacent targets. Overall, our results indicate that follow-through contextual cues influence activity of both implicit and explicit processes during separation of motor memories. Furthermore, the follow-through context might activate, in part, top-down cognitive factors that influence not only the dynamics of the explicit learning but also the implicit process.


2020 ◽  
Author(s):  
Lot Sternheim ◽  
Miriam Wickham ◽  
Unna Danner ◽  
Todd Maddox ◽  
Vincent Filoteo ◽  
...  

Abstract Backgroundcognitive disturbances such as impairments in learning are thought to play a role in adult Anorexia Nervosa (AN). It is remains unclear to what extend these disturbances result from starvation of the brain, or relate to an abnormal premorbid cognitive profile. This study investigates learning processes in adolescents with AN, hypothesizing that implicit learning is intact, as found previously in explicit learning tasks. Secondly, we hypothesized that anxiety and depression symptoms, inherent to AN, are associated to learning processes in AN, and thirdly we aimed to explore any cultural learning differences in individuals from the Netherlands or the USA. Methods: in total 46 adolescents diagnosed with AN and 44 control participants were administered an implicit category learning task in which they were asked to categorize simple perceptual stimuli (Gabor patches) based on a linear integration (i.e., an implicit task) of orientation and spatial frequency of the stimulus. A subgroup of adolescents also completed a task assessing explicit learning. Resultsmodel-based analyses indicated that adolescents with AN performed significantly more accurately compared to their healthy peers regardless whether they used the optimal strategy or not. Depression and anxiety did not relate to learning performance in the AN group, no cultural differences in learning were found. Conclusionsoverall, our findings of augmented implicit and explicit learning in adolescents with AN corroborate recent studies that suggested higher stimulus-response learning during prediction error paradigms. Learning disturbances in adult AN may then be due to malnourishment, highlighting the importance of early recognition and refeeding in treatments for AN.


2017 ◽  
Author(s):  
Natalia Sánchez ◽  
James M. Finley

AbstractChanges in the control of the lower extremities post-stroke lead to persistent biomechanical asymmetries during walking. These asymmetries are associated with an increase in energetic cost, leading to the possibility that reduction of asymmetry can improve economy. However, the influence of asymmetry on economy may depend on the direction and cause of asymmetry. For example, impairments with paretic limb advancement may result in shorter paretic steps while deficits in paretic support or propulsion result in shorter non-paretic steps. Given differences in the underlying impairments responsible for each type of step length asymmetry, the capacity to reduce asymmetry, and the associated changes in energetic cost may not be consistent across this population. Here, we identified factors explaining individual differences in the capacity to voluntarily reduce step length asymmetry and modify energetic cost during walking. Twenty-four individuals post-stroke walked on a treadmill with visual feedback of their step lengths to aid explicit modification of asymmetry. We found that individuals who naturally took longer paretic steps had a greater capacity to reduce asymmetry, and were better able to transfer the effects of training to over-ground walking. In addition, baseline energetic cost was negatively correlated with reductions in cost, such that participants with a more economical gait were more likely to reduce energetic cost by improving symmetry. These results demonstrate that many stroke survivors retain the capacity to voluntarily walk more symmetrically on a treadmill and over-ground. However, whether reductions in asymmetry reduce metabolic cost depends on individual differences in impairments affecting locomotor function.


Author(s):  
Gefen Dawidowicz ◽  
Yuval Shaine ◽  
Firas Mawase

Acquisition of multiple motor skills without interference is a remarkable ability in daily life. During adaptation to opposing perturbations, a common paradigm to study this ability, each perturbation can be successfully learned when a contextual follow-through movement is associated with the direction of the perturbation. It is still unclear, however, to what extent this learning engages the cognitive explicit process and the implicit process. Here, we untangled the individual contributions of the explicit and implicit components while participants learned opposing visuomotor perturbations, with a second unperturbed follow-through movement. In Exp. 1 we replicated previous adaptation results and showed that follow-through movements also allow learning for opposing visuomotor rotations. For one group of participants in Exp. 2 we isolated strategic explicit learning, while for another group we isolated the implicit component. Our data showed that opposing perturbations could be fully learned by explicit strategies; but when strategy was restricted, distinct implicit processes contributed to learning. In Exp.3, we examined whether learning is influenced by the disparity between the follow-through contexts. We found that the location of follow-through targets had little effect on total learning, yet it led to more instances in which participants failed to learn the task. In Exp. 4, we explored the generalization capability to untrained targets. Participants showed near-flat generalization of the implicit and explicit processes. Overall, our results indicate that follow-through contextual cues might activate, in part, top-down cognitive factors that influence not only the dynamics of the explicit learning, but also the implicit process.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Lot C. Sternheim ◽  
Miriam I. Wickham ◽  
Unna N. Danner ◽  
Todd W. Maddox ◽  
Vincent J. Filoteo ◽  
...  

Abstract Background Cognitive disturbances such as impairments in learning are thought to play a role in adult Anorexia Nervosa (AN). It is remains unclear to what extent these disturbances result from starvation of the brain, or relate to an abnormal premorbid cognitive profile. This study investigates learning processes in adolescents with AN, hypothesizing that implicit learning is intact, as found previously in explicit learning tasks. Secondly, we hypothesized that anxiety and depression symptoms, inherent to AN, are associated to learning processes in AN. Methods In total 46 adolescents diagnosed with AN and 44 control participants were administered an implicit category learning task in which they were asked to categorize simple perceptual stimuli (Gabor patches) based on a linear integration (i.e., an implicit task) of orientation and spatial frequency of the stimulus. A subgroup of adolescents (n = 38) also completed a task assessing explicit learning. Results Model-based analyses indicated that adolescents with AN performed significantly more accurately compared to their healthy peers regardless of whether they used the optimal strategy or not. Depression and anxiety did not relate to learning performance in the AN group. Conclusions Overall, our findings of augmented implicit and explicit learning in adolescents with AN corroborate recent studies that suggested higher stimulus-response learning during prediction error paradigms. Learning disturbances in adult AN may then be at least partly due to long-term malnourishment, highlighting the importance of early recognition and refeeding in treatments for AN.


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