Variability in locomotor dynamics reveals the critical role of feedback in task control
- Johns Hopkins University, United States
- Middle East Technical University, Turkey
- New Jersey Institute of Technology, United States
Abstract
Animals vary considerably in size, shape, and physiological features across individuals, but yet achieve remarkably similar behavioral performances. We examined how animals compensate for morphophysiological variation by measuring the system dynamics of individual knifefish (Eigenmannia virescens) in a refuge tracking task. Kinematic measurements of Eigenmannia were used to generate individualized estimates of each fish's locomotor plant and controller, revealing substantial variability between fish. To test the impact of this variability on behavioral performance, these models were used to perform simulated 'brain transplants'-computationally swapping controllers and plants between individuals. We found that simulated closed-loop performance was robust to mismatch between plant and controller. This suggests that animals rely on feedback rather than precisely tuned neural controllers to compensate for morphophysiological variability.
Data availability
An archived version of the dataset and analysis code will be made available through the Johns Hopkins University Data Archive.
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Data associated with Variability in locomotor dynamics reveals the critical role of feedback in task controlJohns Hopkins University Data Archive.
Article and author information
Author details
Funding
National Science Foundation (1557895)
- Noah J Cowan
National Science Foundation (1557858)
- Eric S Fortune
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All experimental procedures used for this study were reviewed and approved by Johns Hopkins (protocol: FI19A178) and Rutgers (protocol: 999900774) Animal Care and Use committees and followed the guidelines given by the National Research Council and the Society for Neuroscience.
Copyright
© 2020, Uyanik et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Variability in locomotor dynamics reveals the critical role of feedback in task control
eLife 9:e51219.
https://doi.org/10.7554/eLife.51219
Further reading
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Moment-to-moment neural variability has been shown to scale positively with the complexity of stimulus input. However, the mechanisms underlying the ability to align variability to input complexity are unknown. Using a combination of behavioral methods, computational modeling, fMRI, MR spectroscopy, and pharmacological intervention, we investigated the role of aging and GABA in neural variability during visual processing. We replicated previous findings that participants expressed higher variability when viewing more complex visual stimuli. Additionally, we found that such variability modulation was associated with higher baseline visual GABA levels and was reduced in older adults. When pharmacologically increasing GABA activity, we found that participants with lower baseline GABA levels showed a drug-related increase in variability modulation while participants with higher baseline GABA showed no change or even a reduction, consistent with an inverted-U account. Finally, higher baseline GABA and variability modulation were jointly associated with better visual-discrimination performance. These results suggest that GABA plays an important role in how humans utilize neural variability to adapt to the complexity of the visual world.
