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- Contribution Type:
- Abstract
- Author(s):
- M. Forano and D.W. Franklin
- Title:
- Modelling the timescales of motor memory formation in dual adaptation
- Abstract:
- Introduction Adaptation to novel dynamics has been well explained by a model dissociating two different timescales: a fast process that learns but also forgets quickly and a slow process that learns slowly but retains more of the learning (Smith et al., 2006). While this model reproduces the main experimental evidences of motor learning, such as savings, spontaneous recovery and interference; it cannot account for dual-adaptation. Indeed, model predictions do not allow simultaneous adaptation, as each context drives the unlearning of the previously learned one. However, experimental studies showed that, given the adequate contextual cue, participants are able to adapt simultaneously to opposing dynamics (Howard et al., 2013). Consequently, this model was expanded, suggesting that dual-adaptation occurs through a single fast process and multiple slow processes (Lee & Schweighofer, 2009), but was only tested against experimental data in a single adaptation phase. In this study, we challenged the model’s structure using computational modelling and by experimentally testing the ability to predict spontaneous recovery in dual adaptation. Methods Participants performed reaching movements to a target and simultaneously adapted to two opposing force fields (adaptation phase), each associated with a contextual cue (workspace visual location). A de-adaptation phase followed where the association between the contextual cues and the force fields were reversed to wash out the previous adaptation. Finally, a sequence of channel trials was used to examine the presence of spontaneous recovery (error clamp phase). Twelve multi-rate models were then fitted to experimental data and compared with a BIC model comparison. Results Participants learned both opposing tasks simultaneously, reducing the motor error by learning the appropriate compensation to the perturbation and displayed spontaneous recovery towards the first learnt dynamics. The analysis of model predictions and the BIC model comparison supported the existence of two fast processes, and extended the model timescales to include a third rate: an ultraslow process. Discussion Our results on experimental data and model comparison showed that dual-adaptation can be best explained by a two-fast-triple-rate model. This new architecture of model can predict the formation of two independent motor memories at three different timescales for our experimental timeframe, but might be extended to more timescales for longer periods of adaptation (Forano and Franklin, 2020). Literature Forano, M., & Franklin, D. W. (2020). Timescales of motor memory formation in dual-adaptation. PLoS Computational Biology, 16(10), e1008373. Howard I.S., Wolpert D.M. & Franklin D.W. (2013). The effect of contextual cues on the encoding of motor memories. Journal of Neurophysiology, 109(10), 2632-2644. Lee J.Y. & Schweighofer, N. (2009). Dual adaptation supports a parallel architecture of motor memory. Journal of Neuroscience, 29(33), 10396-10404. Smith M.A., Ghazizadeh A. & Shadmehr, R. (2006). Interacting adaptive processes with different timescales underlie short-term motor learning. PLoS Biology. 4(6), e179.
- Month:
- Sep
- Year:
- 2022
- URL:
- https://www.sport.kit.edu/dvs-Jahrestagung-Sportmotorik-2022/Wissenschaftliches-Programm.php
- Language:
- en
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