Evolution and Development of a Central Pattern Generator for the Swimming of a Lamprey

1999 ◽  
Vol 5 (3) ◽  
pp. 247-269 ◽  
Author(s):  
Auke Jan Ijspeert ◽  
Jérôme Kodjabachian
Keyword(s):  
Neural Control ◽  
Fitness Function ◽  
Central Pattern Generators ◽  
The Body ◽  
Programming Approach ◽  
Two Dimensional ◽  
Developmental Programs ◽  
Cellular Division ◽  
Input Signals ◽  
Pattern Generators

This article describes the design of neural control architectures for locomotion using an evolutionary approach. Inspired by the central pattern generators found in animals, we develop neural controllers that can produce the patterns of oscillations necessary for the swimming of a simulated lamprey. This work is inspired by Ekeberg's neuronal and mechanical model of a lamprey [11] and follows experiments in which swimming controllers were evolved using a simple encoding scheme [25, 26]. Here, controllers are developed using an evolutionary algorithm based on the SGOCE encoding [31, 32] in which a genetic programming approach is used to evolve developmental programs that encode the growing of a dynamical neural network. The developmental programs determine how neurons located on a two-dimensional substrate produce new cells through cellular division and how they form efferent or afferent interconnections. Swimming controllers are generated when the growing networks eventually create connections to the muscles located on both sides of the rectangular substrate. These muscles are part of a two-dimensional mechanical simulation of the body of the lamprey in interaction with water. The motivation of this article is to develop a method for the design of control mechanisms for animal-like locomotion. Such a locomotion is characterized by a large number of actuators, a rhythmic activity, and the fact that efficient motion is only obtained when the actuators are well coordinated. The task of the control mechanism is therefore to transform commands concerning the speed and direction of motion into the signals sent to the multiple actuators. We define a fitness function, based on several simulations of the controller with different commands settings, that rewards the capacity of modulating the speed and the direction of swimming in response to simple, varying input signals. Central pattern generators are thus evolved capable of producing the relatively complex patterns of oscillations necessary for swimming. The best solutions generate traveling waves of neural activity, and propagate, similarly to the swimming of a real lamprey, undulations of the body from head to tail propelling the lamprey forward through water. By simply varying the amplitude of two input signals, the speed and the direction of swimming can be modulated.

Neural Control of Swimming in Nudipleura Molluscs

2017 ◽  
pp. 438-450
Author(s):  
Paul S. Katz ◽  
Akira Sakurai
Keyword(s):  
Neural Control ◽  
Central Pattern Generators ◽  
Swimming Behavior ◽  
Neural Mechanisms ◽  
The Other ◽  
Neural Basis ◽  
Tritonia Diomedea ◽  
Pleurobranchaea Californica ◽  
Sea Slugs ◽  
Pattern Generators

This article compares the neural basis for swimming in sea slugs belonging to the Nudipleura clade of molluscs. There are two primary forms of swimming. One, dorsal/ventral (DV) body flexions, is typified by Tritonia diomedea and Pleurobranchaea californica. Although Tritonia and Pleurobranchaea evolved DV swimming independently, there are at least two homologous neurons in the central pattern generators (CPGs) underlying DV swimming in these species. Furthermore, both species have serotonergic neuromodulation of synaptic strength intrinsic to their CPGs. The other form of swimming is with alternating left/right (LR) body flexions. Melibe and Dendronotus belong to a clade of species that all swim with LR body flexions. Although the swimming behavior is homologous, their swim CPGs differ in both cellular composition and in the details of the neural mechanisms. Thus, similar behaviors have independently evolved through parallel use of homologous neurons, and homologous behaviors can be produced by different neural mechanisms.

Head Motion Stabilization During Quadruped Robot Locomotion

2011 ◽  
Vol 2 (1) ◽  
pp. 39-62 ◽  
Author(s):  
Miguel Oliveira ◽  
Cristina P. Santos ◽  
Lino Costa ◽  
Ana Rocha ◽  
Manuel Ferreira
Keyword(s):  
Global Optimization ◽  
Head Movement ◽  
Nonlinear Dynamical Systems ◽  
Fitness Function ◽  
Central Pattern Generators ◽  
Quadruped Robot ◽  
Biologically Inspired ◽  
Nonlinear Dynamical ◽  
Pattern Generators ◽  
The One

In this work, the authors propose a combined approach based on a controller architecture that is able to generate locomotion for a quadruped robot and a global optimization algorithm to generate head movement stabilization. The movement controllers are biologically inspired in the concept of Central Pattern Generators (CPGs) that are modelled based on nonlinear dynamical systems, coupled Hopf oscillators. This approach allows for explicitly specified parameters such as amplitude, offset and frequency of movement and to smoothly modulate the generated oscillations according to changes in these parameters. The overall idea is to generate head movement opposed to the one induced by locomotion, such that the head remains stabilized. Thus, in order to achieve this desired head movement, it is necessary to appropriately tune the CPG parameters. Three different global optimization algorithms search for this best set of parameters. In order to evaluate the resulting head movement, a fitness function based on the Euclidean norm is investigated. Moreover, a constraint-handling technique based on tournament selection was implemented.

Central Resetting of Neuromuscular Steady States May Underlie Rhythmical Arm Movements

2006 ◽  
Vol 96 (3) ◽  
pp. 1124-1134 ◽  
Author(s):  
Ksenia I. Ustinova ◽  
Anatol G. Feldman ◽  
Mindy F. Levin
Keyword(s):  
Steady State ◽  
Muscle Activation ◽  
Central Pattern Generators ◽  
Steady States ◽  
The Body ◽  
Proprioceptive Reflexes ◽  
Natural Tendency ◽  
Equilibrium Configurations ◽  
Pattern Generators ◽  
State Configuration

Changing the steady-state configuration of the body or its segments may be an important function of central pattern generators for locomotion and other rhythmical movements. Thereby, muscle activation, forces, and movement may emerge following a natural tendency of the neuromuscular system to achieve the current steady-state configuration. To verify that transitions between different steady states occur during rhythmical movements, we asked standing subjects to swing one or both arms synchronously or reciprocally at ∼0.8 Hz from the shoulder joints. In randomly selected cycles, one arm was transiently arrested by an electromagnetic device. Swinging resumed after some delay and phase resetting. During bilateral swinging, the nonperturbed arm often stopped before resuming swinging at a position that was close to either the extreme forward or the extreme backward arm position observed before the perturbation. Oscillations usually resumed when both arms arrived at similar extreme positions when a synchronous bilateral pattern was initially produced or at the opposite positions if the initial pattern was reciprocal. Results suggest that a central generator controls both arms as a coherent unit by producing transitions between its steady state (equilibrium) positions. By controlling these positions, the system may define the spatial boundaries of movement. At these positions, the system may halt the oscillations, resume them at a new phase (as observed in the present study), or initiate a new motor action. Our findings are relevant to locomotion and suggest that walking may also be generated by transitions between several equilibrium configurations of the body, possibly accomplished by modulation and gating of proprioceptive reflexes.

scholarly journals An autonomous tail-beating cycle period expressed by a region-specific swimming pattern generator in the Ciona larva

2021 ◽  
Author(s):  
Takashi Hara ◽  
Shuya Hasegawa ◽  
Yasushi Iwatani ◽  
Atsuo S. Nishino
Keyword(s):  
Central Pattern Generators ◽  
Sister Group ◽  
Pattern Generator ◽  
The Body ◽  
Periodic Pattern ◽  
Cycle Period ◽  
Swimming Pattern ◽  
Aquatic Vertebrates ◽  
Pattern Generators ◽  
Region 10

Swimming locomotion in aquatic vertebrates, such as fish and tadpoles, is expressed through orchestrated operations of central pattern generators. These parallel neuronal circuits are ubiquitously distributed and mutually coupled along the spinal cord to express undulation patterns accommodated to efferent and afferent inputs. While such sets of schemes have been shown in vertebrates, the evolutionary origin of those mechanisms along the chordate phylogeny remains unclear. Ascidians, representing a sister group of vertebrates, give rise to tadpole larvae that freely swim in seawater. In this study, we tried to locate the swimming pattern generator in larvae of the ascidian Ciona by examining locomotor ability of segmented body fragments. Our experiments demonstrated necessary and sufficient pattern generator activity in a short region (~10% of the body length as the longest estimation) including the trunk-tail junction but excluding most of the trunk and tail with major sensory apparatuses therein. Moreover, we found that these "mid-piece" body fragments express periodic tail beating bursts with ~20-s intervals without any exogenous stimuli. Comparisons among temporal patterns of tail beating bursts expressed by the mid-piece fragments and by whole larvae placed under different sensory conditions suggested that the presence of parts other than the critical mid-piece had effects to shorten swimming burst intervals, especially in the dark, and also to expand the variance in burst durations. We propose that Ciona larvae perform swimming as modified representations of autonomous and periodic pattern generator drives, which operate locally in the region of the trunk-tail junction.

scholarly journals Towards an Understanding of Control of Complex Rhythmical “Wavelike” Coordination in Humans

2020 ◽  
Vol 10 (4) ◽  
pp. 215
Author(s):  
Ross Howard Sanders ◽  
Daniel J. Levitin
Keyword(s):  
Neural Control ◽  
Central Pattern Generators ◽  
Future Research ◽  
Front Crawl ◽  
Screening Criteria ◽  
Pattern Generators ◽  
Complex Relationships ◽  
Cns Control

How does the human neurophysiological system self-organize to achieve optimal phase relationships among joints and limbs, such as in the composite rhythms of butterfly and front crawl swimming, drumming, or dancing? We conducted a systematic review of literature relating to central nervous system (CNS) control of phase among joint/limbs in continuous rhythmic activities. SCOPUS and Web of Science were searched using keywords “Phase AND Rhythm AND Coordination”. This yielded 1039 matches from which 23 papers were extracted for inclusion based on screening criteria. The empirical evidence arising from in-vivo, fictive, in-vitro, and modelling of neural control in humans, other species, and robots indicates that the control of movement is facilitated and simplified by innervating muscle synergies by way of spinal central pattern generators (CPGs). These typically behave like oscillators enabling stable repetition across cycles of movements. This approach provides a foundation to guide the design of empirical research in human swimming and other limb independent activities. For example, future research could be conducted to explore whether the Saltiel two-layer CPG model to explain locomotion in cats might also explain the complex relationships among the cyclical motions in human swimming.

scholarly journals Evaluating the energetics of entrainment in a human–machine coupled oscillator system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryan T. Schroeder ◽  
James L. Croft ◽  
John E. A. Bertram
Keyword(s):  
Central Pattern Generators ◽  
Metabolic Cost ◽  
The Body ◽  
Vertical Force ◽  
Wide Range ◽  
Metabolic Expenditure ◽  
Pattern Generators ◽  
Positive Work ◽  
Phase Relationships

AbstractDuring locomotion, humans sometimes entrain (i.e. synchronize) their steps to external oscillations: e.g. swaying bridges, tandem walking, bouncy harnesses, vibrating treadmills, exoskeletons. Previous studies have discussed the role of nonlinear oscillators (e.g. central pattern generators) in facilitating entrainment. However, the energetics of such interactions are unknown. Given substantial evidence that humans prioritize economy during locomotion, we tested whether reduced metabolic expenditure is associated with human entrainment to vertical force oscillations, where frequency and amplitude were prescribed via a custom mechatronics system during walking. Although metabolic cost was not significantly reduced during entrainment, individuals expended less energy when the oscillation forces did net positive work on the body and roughly selected phase relationships that maximize positive work. It is possible that individuals use mechanical cues to infer energy cost and inform effective gait strategies. If so, an accurate prediction may rely on the relative stability of interactions with the environment. Our results suggest that entrainment occurs over a wide range of oscillation parameters, though not as a direct priority for minimizing metabolic cost. Instead, entrainment may act to stabilize interactions with the environment, thus increasing predictability for the effective implementation of internal models that guide energy minimization.

scholarly journals Features of hand-foot crawling behavior in human adults

2012 ◽  
Vol 107 (1) ◽  
pp. 114-125 ◽  
Author(s):  
M. J. MacLellan ◽  
Y. P. Ivanenko ◽  
G. Cappellini ◽  
F. Sylos Labini ◽  
F. Lacquaniti
Keyword(s):  
Spinal Cord ◽  
Neural Control ◽  
The Body ◽  
Bipedal Walking ◽  
Emg Activity ◽  
Gradual Transition ◽  
Spatiotemporal Pattern ◽  
Plantar Flexors ◽  
Pattern Generators ◽  
Hands And Feet

Interlimb coordination of crawling kinematics in humans shares features with other primates and nonprimate quadrupeds, and it has been suggested that this is due to a similar organization of the locomotor pattern generators (CPGs). To extend the previous findings and to further explore the neural control of bipedal vs. quadrupedal locomotion, we used a crawling paradigm in which healthy adults crawled on their hands and feet at different speeds and at different surface inclinations (13°, 27°, and 35°). Ground reaction forces, limb kinematics, and electromyographic (EMG) activity from 26 upper and lower limb muscles on the right side of the body were collected. The EMG activity was mapped onto the spinal cord in approximate rostrocaudal locations of the motoneuron pools to characterize the general features of cervical and lumbosacral spinal cord activation. The spatiotemporal pattern of spinal cord activity significantly differed between quadrupedal and bipedal gaits. In addition, participants exhibited a large range of kinematic coordination styles (diagonal vs. lateral patterns), which is in contrast to the stereotypical kinematics of upright bipedal walking, suggesting flexible coupling of cervical and lumbosacral pattern generators. Results showed strikingly dissimilar directional horizontal forces for the arms and legs, considerably retracted average leg orientation, and substantially smaller sacral vs. lumbar motoneuron activity compared with quadrupedal gait in animals. A gradual transition to a more vertical body orientation (increasing the inclination of the treadmill) led to the appearance of more prominent sacral activity (related to activation of ankle plantar flexors), typical of bipedal walking. The findings highlight the reorganization and adaptation of CPG networks involved in the control of quadrupedal human locomotion and a high specialization of the musculoskeletal apparatus to specific gaits.

scholarly journals Towards an Understanding of Control of Complex Rhythmical ‘Wavelike’ Coordination in Humans

2020 ◽  
Author(s):  
Ross Howard Sanders ◽  
Daniel J. Levitin
Keyword(s):  
Neural Control ◽  
Central Pattern Generators ◽  
Future Research ◽  
Front Crawl ◽  
Screening Criteria ◽  
Pattern Generators ◽  
Complex Relationships ◽  
Cns Control

How does the human neurophysiological system self-organize to achieve optimal phase relationships among joints and limbs, such as in the composite rhythms of butterfly and front crawl swimming, drumming, or dancing? We conducted a systematic review of literature relating to CNS control of phase among joint/limbs in continuous rhythmic activities. SCOPUS and Web of Science were searched using keywords ‘Phase AND Rhythm AND Coordination’. This yielded 998 matches from which 23 papers were extracted for inclusion based on screening criteria. The empirical evidence arising from in-vivo, fictive, in-vitro, and modelling of neural control in humans, other species, and robots indicates that the control of movement is facilitated and simplified by innervating muscle synergies by way of spinal central pattern generators (CPGs). These typically behave like oscillators enabling stable repetition across cycles of movements. This approach provides a foundation to guide the design of empirical research in human swimming and other limb independent activities. For example, future research could be conducted to explore whether the two-layer CPG model proposed by Saltiel et al [1] to explain locomotion in cats might also explain the complex relationships among the cyclical motions in human swimming.

scholarly journals Speed dependency in α-motoneuron activity and locomotor modules in human locomotion: indirect evidence for phylogenetically conserved spinal circuits

2017 ◽  
Vol 284 (1851) ◽  
pp. 20170290 ◽  
Author(s):  
Hikaru Yokoyama ◽  
Tetsuya Ogawa ◽  
Masahiro Shinya ◽  
Noritaka Kawashima ◽  
Kimitaka Nakazawa
Keyword(s):  
High Speed ◽  
Neural Control ◽  
Activity Patterns ◽  
Central Pattern Generators ◽  
Indirect Evidence ◽  
Speed Control ◽  
Human Locomotion ◽  
Control Mechanisms ◽  
Activation Patterns ◽  
Pattern Generators

Coordinated locomotor muscle activity is generated by the spinal central pattern generators (CPGs). Vertebrate studies have demonstrated the following two characteristics of the speed control mechanisms of the spinal CPGs: (i) rostral segment activation is indispensable for achieving high-speed locomotion; and (ii) specific combinations between spinal interneuronal modules and motoneuron (MN) pools are sequentially activated with increasing speed. Here, to investigate whether similar control mechanisms exist in humans, we examined spinal neural activity during varied-speed locomotion by mapping the distribution of MN activity in the spinal cord and extracting locomotor modules, which generate basic MN activation patterns. The MN activation patterns and the locomotor modules were analysed from multi-muscle electromyographic recordings. The reconstructed MN activity patterns were divided into the following three patterns depending on the speed of locomotion: slow walking, fast walking and running. During these three activation patterns, the proportion of the activity in rostral segments to that in caudal segments increased as locomotion speed increased. Additionally, the different MN activation patterns were generated by distinct combinations of locomotor modules. These results are consistent with the speed control mechanisms observed in vertebrates, suggesting phylogenetically conserved spinal mechanisms of neural control of locomotion.

Head Motion Stabilization During Quadruped Robot Locomotion

2014 ◽  
pp. 41-65
Author(s):  
Miguel Oliveira ◽  
Cristina P. Santos ◽  
Lino Costa ◽  
Ana Maria A. C. Rocha ◽  
Manuel Ferreira
Keyword(s):  
Global Optimization ◽  
Head Movement ◽  
Nonlinear Dynamical Systems ◽  
Fitness Function ◽  
Central Pattern Generators ◽  
Quadruped Robot ◽  
Biologically Inspired ◽  
Nonlinear Dynamical ◽  
Pattern Generators ◽  
The One

In this work, the authors propose a combined approach based on a controller architecture that is able to generate locomotion for a quadruped robot and a global optimization algorithm to generate head movement stabilization. The movement controllers are biologically inspired in the concept of Central Pattern Generators (CPGs) that are modelled based on nonlinear dynamical systems, coupled Hopf oscillators. This approach allows for explicitly specified parameters such as amplitude, offset and frequency of movement and to smoothly modulate the generated oscillations according to changes in these parameters. The overall idea is to generate head movement opposed to the one induced by locomotion, such that the head remains stabilized. Thus, in order to achieve this desired head movement, it is necessary to appropriately tune the CPG parameters. Three different global optimization algorithms search for this best set of parameters. In order to evaluate the resulting head movement, a fitness function based on the Euclidean norm is investigated. Moreover, a constraint-handling technique based on tournament selection was implemented.

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