scholarly journals Implicit adaptation to mirror-reversal is in the correct coordinate system but the wrong direction

2021 ◽  
Author(s):  
Tianhe Wang ◽  
Jordan Taylor
Keyword(s):  
Coordinate System ◽  
Implicit Learning ◽  
Visuomotor Adaptation ◽  
Separate Experiment ◽  
Reversal Task ◽  
Implicit Processes ◽  
Mirror Reversal ◽  
Wrong Direction ◽  
Polar Coordinate ◽  
Dependent Learning

Learning in visuomotor adaptation tasks is the result of both explicit and implicit processes. Explicit processes, operationalized as re-aiming an intended movement to a new goal, account for the lion's share of learning while implicit processes, operationalized as error-dependent learning that gives rise to aftereffects, appear to be highly constrained. The limitations of implicit learning are highlighted in the mirror-reversal task, where implicit corrections act in opposition to performance. This is surprising given the mirror-reversal task has been viewed as emblematic of implicit learning. One potential confound of these studies is that both explicit and implicit processes were allowed to operate concurrently, which may interact, potentially in opposition. Therefore, we sought to further characterized implicit learning in a mirror-reversal task with a clamp design to isolate implicit learning from explicit strategies. We confirmed that implicit adaptation is in the wrong direction for mirror-reversal and operates as if the perturbation were a rotation, and only showed a moderate attenuation after three days of training. This result raised the question of whether implicit adaptation blindly operates as though perturbations were a rotation. In a separate experiment, which directly compared a mirror-reversal and a rotation, we found that implicit adaptation operates in a proper coordinate system for different perturbations: adaptation to a mirror-reversal and rotational perturbation is more consistent with Cartesian and polar coordinate systems, respectively. It remains an open question why implicit process would be flexible to the coordinate system of a perturbation but continue to be directed inappropriately.

scholarly journals Implicit adaptation to mirror-reversal is in the correct coordinate system but the wrong direction

2021 ◽  
Author(s):  
Tianhe Wang ◽  
Jordan A Taylor
Keyword(s):  
Coordinate System ◽  
Implicit Learning ◽  
Significant Proportion ◽  
Visuomotor Adaptation ◽  
Separate Experiment ◽  
Reversal Task ◽  
Implicit Processes ◽  
Mirror Reversal ◽  
Wrong Direction ◽  
Dependent Learning

Learning in visuomotor adaptation tasks is the result of both explicit and implicit processes. Explicit processes, operationalized as re-aiming an intended movement to a new goal, account for a significant proportion of learning. However, implicit processes, operationalized as error-dependent learning that gives rise to aftereffects, appear to be highly constrained. The limitations of implicit learning are highlighted in the mirror-reversal task, where implicit corrections act in opposition to performance. This is surprising given the mirror-reversal task has been viewed as emblematic of implicit learning. One potential issue not being considered in these studies is that both explicit and implicit processes were allowed to operate concurrently, which may interact, potentially in opposition. Therefore, we sought to further characterized implicit learning in a mirror-reversal task with a clamp design to isolate implicit learning from explicit strategies. We confirmed that implicit adaptation is in the wrong direction for mirror-reversal and operates as if the perturbation were a rotation, and only showed a moderate attenuation after three days of training. This result raised the question of whether implicit adaptation blindly operates as though perturbations were a rotation. In a separate experiment, which directly compared a mirror-reversal and a rotation, we found that implicit adaptation operates in a proper coordinate system for different perturbations: adaptation to a mirror-reversal and rotational perturbation is more consistent with Cartesian and polar coordinate systems, respectively. It remains an open question why implicit process would be flexible to the coordinate system of a perturbation but continue to be directed inappropriately.

scholarly journals Taking aim at the perceptual side of motor learning: Exploring how explicit and implicit learning encode perceptual error information through depth vision

2021 ◽  
Author(s):  
Carlo Campagnoli ◽  
Fulvio Domini ◽  
Jordan A Taylor
Keyword(s):  
Motor Learning ◽  
Implicit Learning ◽  
Visuomotor Adaptation ◽  
Perceptual Task ◽  
Implicit Processes ◽  
Implicit Motor Learning ◽  
Input Side ◽  
Group A ◽  
Delayed Group ◽  
Depth Condition

Motor learning in visuomotor adaptation tasks results from both explicit and implicit processes, each responding differently to an error signal. While the motor output side of these processes is extensively studied, their visual input side is relatively unknown. We investigated if and how depth perception affects the computation of error information by explicit and implicit motor learning. Two groups of participants threw virtual darts at a virtual dartboard while receiving perturbed endpoint feedback. The Delayed group was allowed to re-aim and their feedback was delayed to emphasize explicit learning, while the Clamped group received clamped cursor feedback which they were told to ignore, and continued to aim straight at the target to emphasize implicit adaptation. Both groups played this game in a highly detailed virtual environment (Depth condition) and in an empty environment (No-Depth condition). The Delayed group showed an increase in error sensitivity under Depth relative to No-Depth conditions. In contrast, the Clamped group adapted to the same degree under both conditions. The movement kinematics of the Delayed participants also changed under the Depth condition, consistent with the target appearing more distant, unlike the Clamped group. A comparison of the Delayed behavioral data with a perceptual task from the same individuals showed that the effect of the Depth condition on the re-aiming direction was consistent with an increase in the scaling of the error distance and size. These findings suggest that explicit and implicit learning processes may rely on different sources of perceptual information.

Patterns of Implicit Learning Below the Level of Conscious Knowledge

2010 ◽  
Vol 24 (2) ◽  
pp. 91-101 ◽  
Author(s):  
Juliana Yordanova ◽  
Rolf Verleger ◽  
Ullrich Wagner ◽  
Vasil Kolev
Keyword(s):  
Implicit Learning ◽  
Explicit Knowledge ◽  
Implicit Knowledge ◽  
Knowledge Generation ◽  
Sleep Stages ◽  
Implicit Processing ◽  
Implicit Processes ◽  
Late Night ◽  
On Line ◽  
On Line Learning

The objective of the present study was to evaluate patterns of implicit processing in a task where the acquisition of explicit and implicit knowledge occurs simultaneously. The number reduction task (NRT) was used as having two levels of organization, overt and covert, where the covert level of processing is associated with implicit associative and implicit procedural learning. One aim was to compare these two types of implicit processes in the NRT when sleep was or was not introduced between initial formation of task representations and subsequent NRT processing. To assess the effects of different sleep stages, two sleep groups (early- and late-night groups) were used where initial training of the task was separated from subsequent retest by 3 h full of predominantly slow wave sleep (SWS) or rapid eye movement (REM) sleep. In two no-sleep groups, no interval was introduced between initial and subsequent NRT performance. A second aim was to evaluate the interaction between procedural and associative implicit learning in the NRT. Implicit associative learning was measured by the difference between the speed of responses that could or could not be predicted by the covert abstract regularity of the task. Implicit procedural on-line learning was measured by the practice-based increased speed of performance with time on task. Major results indicated that late-night sleep produced a substantial facilitation of implicit associations without modifying individual ability for explicit knowledge generation or for procedural on-line learning. This was evidenced by the higher rate of subjects who gained implicit knowledge of abstract task structure in the late-night group relative to the early-night and no-sleep groups. Independently of sleep, gain of implicit associative knowledge was accompanied by a relative slowing of responses to unpredictable items suggesting reciprocal interactions between associative and motor procedural processes within the implicit system. These observations provide evidence for the separability and interactions of different patterns of processing within implicit memory.

scholarly journals Implicit motor learning within three trials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jennifer E. Ruttle ◽  
Bernard Marius ’t Hart ◽  
Denise Y. P. Henriques
Keyword(s):  
Motor Learning ◽  
Implicit Learning ◽  
Time Course ◽  
Skills Training ◽  
Implicit Processes ◽  
Training Performance ◽  
Slow Development ◽  
Implicit Motor Learning ◽  
Implicit Motor ◽  
And Shifts

AbstractIn motor learning, the slow development of implicit learning is traditionally taken for granted. While much is known about training performance during adaptation to a perturbation in reaches, saccades and locomotion, little is known about the time course of the underlying implicit processes during normal motor adaptation. Implicit learning is characterized by both changes in internal models and state estimates of limb position. Here, we measure both as reach aftereffects and shifts in hand localization in our participants, after every training trial. The observed implicit changes were near asymptote after only one to three perturbed training trials and were not predicted by a two-rate model’s slow process that is supposed to capture implicit learning. Hence, we show that implicit learning is much faster than conventionally believed, which has implications for rehabilitation and skills training.

Natural Frequencies and Mode Shapes of Elliptic Plates With Boundary Characteristic Orthogonal Polynomials As Assumed Shape Functions

1991 ◽  
Author(s):  
C. Rajalingham ◽  
R. B. Bhat ◽  
G. D. Xistris
Keyword(s):  
Coordinate System ◽  
Orthogonal Polynomials ◽  
Natural Frequencies ◽  
Ritz Method ◽  
Mode Shapes ◽  
Polar Coordinate System ◽  
Free Boundaries ◽  
Natural Modes ◽  
Polar Coordinate ◽  
Boundary Characteristic

Abstract The natural frequencies and natural modes of vibration of uniform elliptic plates with clamped, simply supported and free boundaries are investigated using Rayleigh-Ritz method. A modified polar coordinate system is used to investigate the problem. Energy expressions in Cartesian coordinate system are transformed into the modified polar coordinate system. Boundary characteristic orthogonal polynomials in the radial direction, and trigonometric functions in the angular direction are used to express the deflection of the plate. These deflection shapes are classified into four basic categories, depending on its symmetrical or antisymmetrical property about the major and minor axes of the ellipse. The first six natural modes in each of the above categories are presented in the form of contour plots.

scholarly journals Aerosol Plume Detection Algorithm Based on Image Segmentation of Scanning Atmospheric Lidar Data

2016 ◽  
Vol 33 (4) ◽  
pp. 697-712 ◽  
Author(s):  
R. Andrew Weekley ◽  
R. Kent Goodrich ◽  
Larry B. Cornman
Keyword(s):  
Coordinate System ◽  
Original Data ◽  
Detection Algorithm ◽  
Polar Coordinate System ◽  
Lidar Data ◽  
Image Processing Algorithm ◽  
Polar Coordinate ◽  
Scanning Lidar ◽  
Performance Statistics ◽  
Background Fields

AbstractAn image-processing algorithm has been developed to identify aerosol plumes in scanning lidar backscatter data. The images in this case consist of lidar data in a polar coordinate system. Each full lidar scan is taken as a fixed image in time, and sequences of such scans are considered functions of time. The data are analyzed in both the original backscatter polar coordinate system and a lagged coordinate system. The lagged coordinate system is a scatterplot of two datasets, such as subregions taken from the same lidar scan (spatial delay), or two sequential scans in time (time delay). The lagged coordinate system processing allows for finding and classifying clusters of data. The classification step is important in determining which clusters are valid aerosol plumes and which are from artifacts such as noise, hard targets, or background fields. These cluster classification techniques have skill since both local and global properties are used. Furthermore, more information is available since both the original data and the lag data are used. Performance statistics are presented for a limited set of data processed by the algorithm, where results from the algorithm were compared to subjective truth data identified by a human.

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