Principles of rhythmic motor pattern generation

1996 ◽  
Vol 76 (3) ◽  
pp. 687-717 ◽  
Author(s):  
E. Marder ◽  
R. L. Calabrese
Keyword(s):  
Motor Pattern ◽  
Pattern Generation ◽  
Rhythmic Movements ◽  
Motor Patterns ◽  
Nervous Systems ◽  
Cellular Processes ◽  
Rhythmic Motor ◽  
Computational Analyses ◽  
Motor Pattern Generation ◽  
Rhythmic Motor Pattern

Rhythmic movements are produced by central pattern-generating networks whose output is shaped by sensory and neuromodulatory inputs to allow the animal to adapt its movements to changing needs. This review discusses cellular, circuit, and computational analyses of the mechanisms underlying the generation of rhythmic movements in both invertebrate and vertebrate nervous systems. Attention is paid to exploring the mechanisms by which synaptic and cellular processes interact to play specific roles in shaping motor patterns and, consequently, movement.

Two interconnected kernels of reciprocally inhibitory interneurons underlie alternating left-right swim motor pattern generation in the mollusk Melibe leonina

2014 ◽  
Vol 112 (6) ◽  
pp. 1317-1328 ◽  
Author(s):  
Akira Sakurai ◽  
Charuni A. Gunaratne ◽  
Paul S. Katz
Keyword(s):  
Motor Pattern ◽  
Pattern Generator ◽  
Swimming Behavior ◽  
Pattern Generation ◽  
Inhibitory Neurons ◽  
Inhibitory Interneurons ◽  
Pedal Ganglion ◽  
Rhythmic Motor ◽  
Fixed Phase ◽  
Motor Pattern Generation

The central pattern generator (CPG) underlying the rhythmic swimming behavior of the nudibranch Melibe leonina (Mollusca, Gastropoda, Heterobranchia) has been described as a simple half-center oscillator consisting of two reciprocally inhibitory pairs of interneurons called swim interneuron 1 (Si1) and swim interneuron 2 (Si2). In this study, we identified two additional pairs of interneurons that are part of the swim CPG: swim interneuron 3 (Si3) and swim interneuron 4 (Si4). The somata of Si3 and Si4 were both located in the pedal ganglion, near that of Si2, and both had axons that projected through the pedal commissure to the contralateral pedal ganglion. These neurons fulfilled the criteria for inclusion as members of the swim CPG: 1) they fired at a fixed phase in relation to Si1 and Si2, 2) brief changes in their activity reset the motor pattern, 3) prolonged changes in their activity altered the periodicity of the motor pattern, 4) they had monosynaptic connections with each other and with Si1 and Si2, and 5) their synaptic actions helped explain the phasing of the motor pattern. The results of this study show that the motor pattern has more complex internal dynamics than a simple left/right alternation of firing; the CPG circuit appears to be composed of two kernels of reciprocally inhibitory neurons, one consisting of Si1, Si2, and the contralateral Si4 and the other consisting of Si3. These two kernels interact with each other to produce a stable rhythmic motor pattern.

scholarly journals Contribution of motoneuron intrinsic properties to fictive motor pattern generation

2011 ◽  
Vol 106 (2) ◽  
pp. 538-553 ◽  
Author(s):  
Terrence M. Wright ◽  
Ronald L. Calabrese
Keyword(s):  
Canonical Ensemble ◽  
Motor Pattern ◽  
Electrical Coupling ◽  
Living System ◽  
Input Pattern ◽  
Pattern Generation ◽  
Intrinsic Properties ◽  
Minimal Set ◽  
Motor Patterns ◽  
Motor Pattern Generation

Previously, we reported a canonical ensemble model of the heart motoneurons that underlie heartbeat in the medicinal leech. The model motoneurons contained a minimal set of electrical intrinsic properties and received a synaptic input pattern based on measurements performed in the living system. Although the model captured the synchronous and peristaltic motor patterns observed in the living system, it did not match quantitatively the motor output observed. Because the model motoneurons had minimal intrinsic electrical properties, the mismatch between model and living system suggests a role for additional intrinsic properties in generating the motor pattern. We used the dynamic clamp to test this hypothesis. We introduced the same segmental input pattern used in the model to motoneurons isolated pharmacologically from their endogenous input in the living system. We show that, although the segmental input pattern determines the segmental phasing differences observed in motoneurons, the intrinsic properties of the motoneurons play an important role in determining their phasing, particularly when receiving the synchronous input pattern. We then used trapezoidal input waveforms to show that the intrinsic properties present in the living system promote phase advances compared with our model motoneurons. Electrical coupling between heart motoneurons also plays a role in shaping motoneuron output by synchronizing the activity of the motoneurons within a segment. These experiments provide a direct assessment of how motoneuron intrinsic properties interact with their premotor pattern of synaptic drive to produce rhythmic output.

Genetic Determinants of Rhythmic Movements Motor Pattern Generation in Drosophila Melanogaster

2014 ◽  
Vol 44 (9) ◽  
pp. 995-1001
Author(s):  
S. A. Fedotov ◽  
Yu. V. Bragina ◽  
N. G. Besedina ◽  
L. V. Danilenkova ◽  
E. A. Kamysheva ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Motor Pattern ◽  
Pattern Generation ◽  
Genetic Determinants ◽  
Rhythmic Movements ◽  
Motor Pattern Generation

scholarly journals Roles of Ascending Inhibition During Two Rhythmic Motor Patterns in Xenopus Tadpoles

1998 ◽  
Vol 79 (5) ◽  
pp. 2316-2328 ◽  
Author(s):  
C. S. Green ◽  
S. R. Soffe
Keyword(s):  
Spinal Cord ◽  
Motor Pattern ◽  
Burst Duration ◽  
Major Influence ◽  
Cycle Period ◽  
Detailed Knowledge ◽  
Motor Patterns ◽  
Rhythmic Motor ◽  
Vertebrate Model ◽  
Longitudinal Pattern

Green, C. S. and S. R. Soffe. Roles of ascending inhibition during two rhythmic motor patterns in Xenopus tadpoles. J. Neurophysiol. 79: 2316–2328, 1998. We have investigated the effects of ascending inhibitory pathways on two centrally generated rhythmic motor patterns in a simple vertebrate model, the young Xenopus tadpole. Tadpoles swim when touched, but when grasped respond with slower, stronger struggling movements during which the longitudinal pattern of motor activity is reversed. Surgical spinal cord transection to remove all ascending connections originating caudal to the transection (in tadpoles immobilized in α-bungarotoxin) did not affect “fictive” swimming generated more rostrally. In contrast, cycle period and burst duration both significantly increased during fictive struggling. Increases were progressively larger with more rostral transection. Blocking caudal activity with the anesthetic MS222 (pharmacological transection) produced equivalent but reversible effects. Reducing crossed-ascending inhibition selectively, either by midsagittal spinal cord division or rostral cord hemisection (1-sided transection) mimicked the effects of transection. Like transection, both operations increased cycle period and burst duration during struggling but did not affect swimming. The changes during struggling were larger with more rostral hemisection. Reducing crossed-ascending inhibition by spinal hemisection also increased the rostrocaudal longitudinal delay during swimming, and the caudorostral delay during struggling. Weakening inhibition globally with low concentrations of the glycine antagonist strychnine (10–100 nM) did not alter swimming cycle period, burst duration, or longitudinal delay. However, strychnine at 10–60 nM decreased cycle period during struggling. It also increased burst duration in some cases, although burst duration increased as a proportion of cycle period in all cases. Strychnine reduced longitudinal delay during struggling, making rostral and caudal activity more synchronous. At 100 nM, struggling was totally disrupted. By combining our results with a detailed knowledge of tadpole spinal cord anatomy, we conclude that inhibition mediated by the crossed-ascending axons of characterized, glycinergic, commissural interneurons has a major influence on the struggling motor pattern compared with swimming. We suggest that this difference is a consequence of the larger, reversed longitudinal delay and the extended burst duration during struggling compared with swimming.

scholarly journals Multiple Types of Control by Identified Interneurons in a Sensory-Activated Rhythmic Motor Pattern

2001 ◽  
Vol 21 (8) ◽  
pp. 2903-2911 ◽  
Author(s):  
György Kemenes ◽  
Kevin Staras ◽  
Paul R. Benjamin
Keyword(s):  
Motor Pattern ◽  
Rhythmic Motor ◽  
Rhythmic Motor Pattern

scholarly journals Molecular Underpinnings of Motor Pattern Generation: Differential Targeting of Shal and Shaker in the Pyloric Motor System

2000 ◽  
Vol 20 (17) ◽  
pp. 6619-6630 ◽  
Author(s):  
Deborah J. Baro ◽  
Amir Ayali ◽  
Lauren French ◽  
Nathaniel L. Scholz ◽  
Jana Labenia ◽  
...  
Keyword(s):  
Motor System ◽  
Motor Pattern ◽  
Pattern Generation ◽  
Motor Pattern Generation
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