A spiral attractor network drives rhythmic locomotion

• Published in: eLife Vol. 6
• Main Authors: Bruno, Angela M, Frost, William N, Humphries, Mark D
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 07.08.2017; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Action Potentials; Animals; Aplysia - cytology; Aplysia - physiology; Aplysia californica; attractors; Brain - physiology; Circadian rhythms; Dynamical systems; Hypotheses; Locomotion; Models, Neurological; Motor Neurons - physiology; Motor task performance; Nerve Net - physiology; Neural circuitry; Neurons; Neuroscience; Observations; Pedal ganglion; Periodicity; Physiological aspects; Population; population dynamics; Rhythms; United States > US; Illinois; Chicago Illinois; attractors; Aplysia californica; neuroscience; population dynamics; locomotion
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.27342

The joint activity of neural populations is high dimensional and complex. One strategy for reaching a tractable understanding of circuit function is to seek the simplest dynamical system that can account for the population activity. By imaging 's pedal ganglion during fictive locomotion, here we show that its population-wide activity arises from a low-dimensional spiral attractor. Evoking locomotion moved the population into a low-dimensional, periodic, decaying orbit - a spiral - in which it behaved as a true attractor, converging to the same orbit when evoked, and returning to that orbit after transient perturbation. We found the same attractor in every preparation, and could predict motor output directly from its orbit, yet individual neurons' participation changed across consecutive locomotion bouts. From these results, we propose that only the low-dimensional dynamics for movement control, and not the high-dimensional population activity, are consistent within and between nervous systems.