scholarly journals The temporal stability of visuomotor adaptation generalization

2017 ◽  
Vol 118 (4) ◽  
pp. 2435-2447 ◽  
Author(s):  
Weiwei Zhou ◽  
Justin Fitzgerald ◽  
Katrina Colucci-Chang ◽  
Karthik G. Murthy ◽  
Wilsaan M. Joiner
Keyword(s):  
Visual Feedback ◽  
Temporal Stability ◽  
Motor Adaptation ◽  
Visuomotor Adaptation ◽  
Time Dependent ◽  
Active Movement ◽  
Temporal Decay ◽  
Temporal Properties ◽  
Three Delays ◽  
Dependent Learning

Movement adaptation in response to systematic motor perturbations exhibits distinct spatial and temporal properties. These characteristics are typically studied in isolation, leaving the interaction largely unknown. Here we examined how the temporal decay of visuomotor adaptation influences the spatial generalization of the motor recalibration. First, we quantified the extent to which adaptation decayed over time. Subjects reached to a peripheral target, and a rotation was applied to the visual feedback of the unseen motion. The retention of this adaptation over different delays (0–120 s) 1) decreased by 29.0 ± 6.8% at the longest delay and 2) was represented by a simple exponential, with a time constant of 22.5 ± 5.6 s. On the basis of this relationship we simulated how the spatial generalization of adaptation would change with delay. To test this directly, we trained additional subjects with the same perturbation and assessed transfer to 19 different locations (spaced 15° apart, symmetric around the trained location) and examined three delays (~4, 12, and 25 s). Consistent with the simulation, we found that generalization around the trained direction (±15°) significantly decreased with delay and distance, while locations >60° displayed near-constant spatiotemporal transfer. Intermediate distances (30° and 45°) showed a difference in transfer across space, but this amount was approximately constant across time. Interestingly, the decay at the trained direction was faster than that based purely on time, suggesting that the spatial transfer of adaptation is modified by concurrent passive (time dependent) and active (movement dependent) processes. NEW & NOTEWORTHY Short-term motor adaptation exhibits distinct spatial and temporal characteristics. Here we investigated the interaction of these features, utilizing a simple motor adaptation paradigm (recalibration of reaching arm movements in response to rotated visual feedback). We examined the changes in the spatial generalization of motor adaptation for different temporal manipulations and report that the spatiotemporal generalization of motor adaptation is generally local and is influenced by both passive (time dependent) and active (movement dependent) learning processes.

Visuomotor adaptation to a visual rotation is gravity dependent

2015 ◽  
Vol 113 (6) ◽  
pp. 1885-1895 ◽  
Author(s):  
Simone Toma ◽  
Alessandra Sciutti ◽  
Charalambos Papaxanthis ◽  
Thierry Pozzo
Keyword(s):  
Energy Expenditure ◽  
Visual Feedback ◽  
Prolonged Exposure ◽  
Temporal Structure ◽  
Vertical Motion ◽  
Visuomotor Adaptation ◽  
Velocity Profiles ◽  
Visuomotor Rotation ◽  
Temporal Properties ◽  
Spatial Parameters

Humans perform vertical and horizontal arm motions with different temporal patterns. The specific velocity profiles are chosen by the central nervous system by integrating the gravitational force field to minimize energy expenditure. However, what happens when a visuomotor rotation is applied, so that a motion performed in the horizontal plane is perceived as vertical? We investigated the dynamic of the adaptation of the spatial and temporal properties of a pointing motion during prolonged exposure to a 90° visuomotor rotation, where a horizontal movement was associated with a vertical visual feedback. We found that participants immediately adapted the spatial parameters of motion to the conflicting visual scene in order to keep their arm trajectory straight. In contrast, the initial symmetric velocity profiles specific for a horizontal motion were progressively modified during the conflict exposure, becoming more asymmetric and similar to those appropriate for a vertical motion. Importantly, this visual effect that increased with repetitions was not followed by a consistent aftereffect when the conflicting visual feedback was absent (catch and washout trials). In a control experiment we demonstrated that an intrinsic representation of the temporal structure of perceived vertical motions could provide the error signal allowing for this progressive adaptation of motion timing. These findings suggest that gravity strongly constrains motor learning and the reweighting process between visual and proprioceptive sensory inputs, leading to the selection of a motor plan that is suboptimal in terms of energy expenditure.

scholarly journals Exposure to auditory feedback delay while speaking induces perceptual habituation but does not mitigate the disruptive effect of delay on speech auditory-motor learning

2020 ◽  
Author(s):  
Douglas M. Shiller ◽  
Takashi Mitsuya ◽  
Ludo Max
Keyword(s):  
Motor Learning ◽  
Visual Feedback ◽  
Auditory Feedback ◽  
Detrimental Effect ◽  
Negative Impact ◽  
Motor Adaptation ◽  
List Type ◽  
Disruptive Effect ◽  
Feedback Delay ◽  
Spectral Perturbation

ABSTRACTPerceiving the sensory consequences of our actions with a delay alters the interpretation of these afferent signals and impacts motor learning. For reaching movements, delayed visual feedback of hand position reduces the rate and extent of visuomotor adaptation, but substantial adaptation still occurs. Moreover, the detrimental effect of visual feedback delay on reach motor learning—selectively affecting its implicit component—can be mitigated by prior habituation to the delay. Auditory-motor learning for speech has been reported to be more sensitive to feedback delay, and it remains unknown whether habituation to auditory delay reduces its negative impact on learning. We investigated whether 30 minutes of exposure to auditory delay during speaking (a) affects the subjective perception of delay, and (b) mitigates its disruptive effect on speech auditory-motor learning. During a speech adaptation task with real-time perturbation of vowel spectral properties, participants heard this frequency-shifted feedback with no delay, 75 ms delay, or 115 ms delay. In the delay groups, 50% of participants had been exposed to the delay throughout a preceding 30-minute block of speaking whereas the remaining participants completed this block without delay. Although habituation minimized awareness of the delay, no improvement in adaptation to the spectral perturbation was observed. Thus, short-term habituation to auditory feedback delays is not effective in reducing the negative impact of delay on speech auditory-motor adaptation. Combined with previous findings, the strong negative effect of delay and the absence of an influence of delay awareness suggest the involvement of predominantly implicit learning mechanisms in speech.HIGHLIGHTSSpeech auditory-motor adaptation to a spectral perturbation was reduced by ~50% when feedback was delayed by 75 or 115 ms.Thirty minutes of prior delay exposure without perturbation effectively reduced participants’ awareness of the delay.However, habituation was ineffective in remediating the detrimental effect of delay on speech auditory-motor adaptation.The dissociation of delay awareness and adaptation suggests that speech auditory-motor learning is mostly implicit.

scholarly journals Neural signatures of reward and sensory error feedback processing in motor learning

2019 ◽  
Vol 121 (4) ◽  
pp. 1561-1574 ◽  
Author(s):  
Dimitrios J. Palidis ◽  
Joshua G. A. Cashaback ◽  
Paul L. Gribble
Keyword(s):  
Visual Feedback ◽  
Motor Adaptation ◽  
Learning Task ◽  
Reward Learning ◽  
P300 Amplitude ◽  
Error Feedback ◽  
Learning Mechanisms ◽  
Visuomotor Rotation ◽  
Feedback Processing ◽  
Motor Commands

At least two distinct processes have been identified by which motor commands are adapted according to movement-related feedback: reward-based learning and sensory error-based learning. In sensory error-based learning, mappings between sensory targets and motor commands are recalibrated according to sensory error feedback. In reward-based learning, motor commands are associated with subjective value, such that successful actions are reinforced. We designed two tasks to isolate reward- and sensory error-based motor adaptation, and we used electroencephalography in humans to identify and dissociate the neural correlates of reward and sensory error feedback processing. We designed a visuomotor rotation task to isolate sensory error-based learning that was induced by altered visual feedback of hand position. In a reward learning task, we isolated reward-based learning induced by binary reward feedback that was decoupled from the visual target. A fronto-central event-related potential called the feedback-related negativity (FRN) was elicited specifically by binary reward feedback but not sensory error feedback. A more posterior component called the P300 was evoked by feedback in both tasks. In the visuomotor rotation task, P300 amplitude was increased by sensory error induced by perturbed visual feedback and was correlated with learning rate. In the reward learning task, P300 amplitude was increased by reward relative to nonreward and by surprise regardless of feedback valence. We propose that during motor adaptation the FRN specifically reflects a reward-based learning signal whereas the P300 reflects feedback processing that is related to adaptation more generally. NEW & NOTEWORTHY We studied the event-related potentials evoked by feedback stimuli during motor adaptation tasks that isolate reward- and sensory error-based learning mechanisms. We found that the feedback-related negativity was specifically elicited by binary reward feedback, whereas the P300 was observed in both tasks. These results reveal neural processes associated with different learning mechanisms and elucidate which classes of errors, from a computational standpoint, elicit the feedback-related negativity and P300.

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