scholarly journals The BCM rule allows a spinal cord model to learn rhythmic movements

2021 ◽  
Author(s):  
Matthias Kohler ◽  
Philipp Stratmann ◽  
Florian Roehrbein ◽  
Alois Knoll ◽  
Alin Albu-Schaeffer ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Visual Cortex ◽  
Learning Rule ◽  
Biomechanical Properties ◽  
Pattern Generator ◽  
Alternative Theory ◽  
Rhythmic Movements ◽  
Animal Locomotion ◽  
Network Properties ◽  
Genetically Determined

Animal locomotion is hypothesized to be controlled by a central pattern generator in the spinal cord. Experiments and models show that rhythm generating neurons and genetically determined network properties could sustain oscillatory output activity suitable for locomotion. However, current CPG models do not explain how a spinal cord circuitry, which has the same basic genetic plan across species, can adapt to control the different biomechanical properties and locomotion patterns existing in these species. Here we demonstrate that rhythmic and alternating movements in pendulum models can be learned by a monolayer spinal cord circuitry model using the BCM learning rule, which has been previously proposed to explain learning in the visual cortex. These results provide an alternative theory to CPG models, because rhythm generating neurons and genetically defined connectivity are not required in our model.

scholarly journals Modeling Post-Scratching Locomotion with Two Rhythm Generators and a Shared Pattern Formation

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 663
Author(s):  
Jesus A. Tapia ◽  
Argelia Reid ◽  
John Reid ◽  
Saul M. Dominguez-Nicolas ◽  
Elias Manjarrez
Keyword(s):  
Spinal Cord ◽  
Pattern Formation ◽  
Effective Connectivity ◽  
Pattern Generator ◽  
Rhythmic Movements ◽  
Common Pattern ◽  
The Mean ◽  
Motor Outputs ◽  
Mean Cycle ◽  
Previous Experimental Study

This study aimed to present a model of post-scratching locomotion with two intermixed central pattern generator (CPG) networks, one for scratching and another for locomotion. We hypothesized that the rhythm generator layers for each CPG are different, with the condition that both CPGs share their supraspinal circuits and their motor outputs at the level of their pattern formation networks. We show that the model reproduces the post-scratching locomotion latency of 6.2 ± 3.5 s, and the mean cycle durations for scratching and post-scratching locomotion of 0.3 ± 0.09 s and 1.7 ± 0.6 s, respectively, which were observed in a previous experimental study. Our findings show how the transition of two rhythmic movements could be mediated by information exchanged between their CPG circuits through routes converging in a common pattern formation layer. This integrated organization may provide flexible and effective connectivity despite the rigidity of the anatomical connections in the spinal cord circuitry.

The neuromuscular basis of rhythmic struggling movements in embryos of Xenopus laevis

1982 ◽  
Vol 99 (1) ◽  
pp. 197-205 ◽  
Author(s):  
J. A. Kahn ◽  
A. Roberts
Keyword(s):  
Xenopus Laevis ◽  
Electrical Activity ◽  
Central Pattern Generator ◽  
Large Amplitude ◽  
Motor Nerve ◽  
Sensory Stimulation ◽  
Pattern Generator ◽  
Rhythmic Movements ◽  
Nerve Activity ◽  
Xenopus Embryos

Xenopus embryos struggle when restrained. Struggling involves rhythmic movements of large amplitude, in which waves of bending propagate from the tail to the head. Underlying this, electrical activity in myotomal muscles occurs in rhythmic bursts that alternate on either side of a segment. Bursts in ipsilateral segments occur in a caudo-rostral sequence. Curarized embryos can generate motor nerve activity in a struggling pattern in the absence of rhythmic sensory stimulation; the pattern is therefore produced by a central pattern generator.

Modulation of Fictive Feeding by Dopamine and Serotonin inAplysia

2000 ◽  
Vol 83 (1) ◽  
pp. 374-392 ◽  
Author(s):  
Evgeni A. Kabotyanski ◽  
Douglas A. Baxter ◽  
Susan J. Cushman ◽  
John H. Byrne
Keyword(s):  
Feeding Activity ◽  
Neural Correlates ◽  
Neural Circuitry ◽  
Pattern Generator ◽  
Synaptic Connections ◽  
Rhythmic Movements ◽  
Motor Programs ◽  
Dopaminergic Cells ◽  
Buccal Ganglia ◽  
Bath Application

The buccal ganglia of Aplysia contain a central pattern generator (CPG) that mediates rhythmic movements of the buccal apparatus during feeding. Activity in this CPG is believed to be regulated, in part, by extrinsic serotonergic inputs and by an intrinsic and extrinsic system of putative dopaminergic cells. The present study investigated the roles of dopamine (DA) and serotonin (5-HT) in regulating feeding movements of the buccal apparatus and properties of the underlying neural circuitry. Perfusing a semi-intact head preparation with DA (50 μM) or the metabolic precursor of catecholamines (l-3–4-dihydroxyphenylalanine, DOPA, 250 μM) induced feeding-like movements of the jaws and radula/odontophore. These DA-induced movements were similar to bites in intact animals. Perfusing with 5-HT (5 μM) also induced feeding-like movements, but the 5-HT-induced movements were similar to swallows. In preparations of isolated buccal ganglia, buccal motor programs (BMPs) that represented at least two different aspects of fictive feeding (i.e., ingestion and rejection) could be recorded. Bath application of DA (50 μM) increased the frequency of BMPs, in part, by increasing the number of ingestion-like BMPs. Bath application of 5-HT (5 μM) did not significantly increase the frequency of BMPs nor did it significantly increase the proportion of ingestion-like BMPs being expressed. Many of the cells and synaptic connections within the CPG appeared to be modulated by DA or 5-HT. For example, bath application of DA decreased the excitability of cells B4/5 and B34, which in turn may have contributed to the DA-induced increase in ingestion-like BMPs. In summary, bite-like movements were induced by DA in the semi-intact preparation, and neural correlates of these DA-induced effects were manifest as an increase in ingestion-like BMPs in the isolated ganglia. Swallow-like movements were induced by 5-HT in the semi-intact preparation. Neural correlates of these 5-HT-induced effects were not evident in isolated buccal ganglia, however.

Lumbar lipomyelomeningocele and sacrococcygeal teratoma in siblings: support for an alternative theory of spinal teratoma formation

2010 ◽  
Vol 5 (6) ◽  
pp. 626-629 ◽  
Author(s):  
Seth F. Oliveria ◽  
Eric M. Thompson ◽  
Nathan R. Selden
Keyword(s):  
Spinal Cord ◽  
Partial Resection ◽  
Sacrococcygeal Teratoma ◽  
Alternative Theory ◽  
Type Iii ◽  
First Child ◽  
Teratoma Formation

Sacrococcygeal teratomas may arise in association with regional developmental errors affecting the caudal embryonic segments and may originate within lumbosacral lipomas. It is therefore possible that sacrococcygeal teratomas and lumbosacral lipomas represent related disorders of embryogenesis. Accordingly, the authors report the cases of 2 siblings. The first child (female) was born with a mature Altman Type III sacrococcygeal teratoma that was resected when she was a neonate. Subsequently, a younger brother was found soon after birth to have an L-4–level lipomyelomeningocele and underwent partial resection and spinal cord untethering at 4 months of age. Although familial forms of each of these conditions have been reported, this is, to the authors' knowledge, the first reported occurrence of lipomyelomeningocele and sacrococcygeal teratoma in siblings. They propose that an inherited regional tendency to developmental error affecting the caudal embryonic segments was shared by these siblings and resulted in spinal teratoma formation in one of them.

Experiments on the central pattern generator for swimming in amphibian embryos

1982 ◽  
Vol 296 (1081) ◽  
pp. 229-243 ◽  
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Nervous System ◽  
Pattern Generator ◽  
Pattern Generation ◽  
Motor Output ◽  
Cycle Period ◽  
Sensory Stimuli ◽  
Swimming Pattern ◽  
Left And Right

The central nervous system of paralysed Xenopus laevis embryos can generate a motor output pattern suitable for swimming locomotion. By recording motor root activity in paralysed embryos with transected nervous systems we have shown that: (a) the spinal cord is capable of swimming pattern generation; (b) swimming pattern generator capability in the hindbrain and spinal cord is distributed; (c) caudal hindbrain is necessary for sustained swimming output after discrete stimulation. By recording similarly from embryos whose central nervous system was divided longitudinally into left and right sides, we have shown that: (a) each side can generate rhythmic motor output with cycle periods like those in swimming; (b) during this activity cycle period increases within an episode, and there is the usual rostrocaudal delay found in swimming; (c) this activity is influenced by sensory stimuli in the same way as swimming activity; ( d) normal phase coupling of the left and right sides can be established by the ventral commissure in the spinal cord. We conclude that interactions between the antagonistic (left and right) motor systems are not necessary for swimming rhythm generation and present a model for swimming pattern generation where autonomous rhythm generators on each side of the nervous system drive the motoneurons. Alternation is achieved by reciprocal inhibition, and activity is initiated and maintained by tonic excitation from the hindbrain.

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