How detailed is the central pattern generation for locomotion?

Grillner, Sten; Zangger, P.

doi:10.1016/0006-8993(75)90401-1

Cited by 229 publications

(95 citation statements)

References 11 publications

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“…For speech movement timing, the general tendency is for the timing of synergistic muscles active during oral closing to be adjusted in a similar manner. Similar to locomotion (Grillner and Zangger, 1975), muscle onsets were found to be highly related, although there was no consistent sequence of onsets across subjects. Previous EMG studies of jaw and lip muscles during speech have also reported inconsistent ordering of muscle onsets across subjects (Sussman et al, 1973;Folkins, 1981).…”

Section: Discussionmentioning

confidence: 89%

Timing factors in the coordination of speech movements

Gracco

1988

J. Neurosci.

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Speech movement coordination involves substantial timing adjustments among multiple degrees of muscles and movement freedom. The present investigation examined the kinematic and muscle timing adjustments associated with the production of select speech movements. For oral closing movements, the timing of the upper lip, lower lip, and jaw peak velocities were found to be tightly coupled, apparently reflecting a coordinative strategy. In contrast, oral opening movements demonstrated reduced temporal coupling and inconsistent sequencing across subjects. Overall, it appears that the temporal organization of speech movements varies with the specific movement goals. In order to evaluate the coordinative patterns for oral closing in detail, the temporal adjustments of multiple perioral muscles associated with the systematic closing peak velocity relations were examined. The relative timing of muscle onsets and peak EMG amplitudes was found to be predictably related to the peak velocity timing variations, suggesting that the motor commands are temporally scaled to generate changes in speaking conditions. It was also found that the mechanical properties of the speech articulators influence movement coordination and can be exploited to maximize movement efficiency. The systematic change in muscle timing characteristics for all synergistic muscles apparently reduces the degrees of freedom to control, thereby facilitating the coordination process.

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Section: Discussionmentioning

confidence: 89%

Timing factors in the coordination of speech movements

Gracco

1988

J. Neurosci.

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“…Originally it was suggested that proprioceptive afferent input was responsible for converting simple alternating flexor and extensor activity into a more complex pattern (Engberg and Lundberg 1969). The persistence of more complex activity patterns following bilateral deafferentation of the hindlimbs in decerebrate cats, however, led Grillner and Zangger (1975) to conclude that the locomotor CPG "… does not simply generate an alternate activation of flexors and extensors but a more delicate pattern that will sequentially start and terminate the activity in the appropriate muscles at the correct instance". Their ideas were further developed in a proposal for a CPG architecture in which separate "modules" or unit burst generators (UBG) controlled subsets of motoneurons (see Grillner 1981).…”

Section: Nih-pa Author Manuscriptmentioning

confidence: 99%

Organization of mammalian locomotor rhythm and pattern generation

McCrea

Rybak

2008

Brain Research Reviews

620

506

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Central pattern generators (CPGs) located in the spinal cord produce the coordinated activation of flexor and extensor motoneurons during locomotion. Previously proposed architectures for the spinal locomotor CPG have included the classical half-center oscillator and the unit burst generator (UBG) comprised of multiple coupled oscillators. We have recently proposed another organization in which a two-level CPG has a common rhythm generator (RG) that controls the operation of the pattern formation (PF) circuitry responsible for motoneuron activation. These architectures are discussed in relation to recent data obtained during fictive locomotion in the decerebrate cat. The data show that the CPG can maintain the period and phase of locomotor oscillations both during spontaneous deletions of motoneuron activity and during sensory stimulation affecting motoneuron activity throughout the limb. The proposed two-level CPG organization has been investigated with a computational model which incorporates interactions between the CPG, spinal circuits and afferent inputs. The model includes interacting populations of spinal interneurons and motoneurons modeled in the Hodgkin-Huxley style. Our simulations demonstrate that a relatively simple CPG with separate RG and PF networks can realistically reproduce many experimental phenomena including spontaneous deletions of motoneuron activity and a variety of effects of afferent stimulation. The model suggests plausible explanations for a number of features of real CPG operation that would be difficult to explain in the framework of the classical single-level CPG organization. Some modeling predictions and directions for further studies of locomotor CPG organization are discussed. KeywordsCPG; computational models; spinal cord; decerebrate; cat Half-center organization of the central pattern generatorMore than 90 years ago, T. Graham Brown (1911) demonstrated that the cat spinal cord can generate a locomotor rhythm in the absence of input from higher centers and afferent feedback. These and later investigations led to the widely accepted concept of central pattern generators Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public Access Author ManuscriptBrain Res Rev. Author manuscript; available in PMC 2009 January 1. Published in final edited form as:Brain Res Rev. 2008 January ; 57(1): 134-146. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript (CPGs) which reside within the central nervous systems of invertebrates and vertebrates and control various rhythmic movements. Graham Brown (1914) also proposed...

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“…Since then there have been many replications of these early experiments (re cently reviewed by Rossignol (1996) [13]). Some authors used the same approach as Brown and they showed that, after transection of the dorsal roots seemingly normal locomotor outputs could be observed in spinal cats [14]. However, transection of the dorsal roots docs not eliminate all afferent input to the spinal cord be cause afferent information can reach the spinal cord by means of unmyelinated [15] and myelinated [16] sensory fibers in the ventral (motor) roots.…”

Section: Evidence For Cpg In Catmentioning

confidence: 99%

“…In the cat several authors have suggested that the activity of hamstrings at end swing could originate from stretch reflexes [2][3][4]. To shed light on this type of question, transection of the dorsal roots was used and it was shown that a seemingly normal locomotor outputs could remain in acute spinal cats [14,17,40]. Although indeed, a striking similarity exists with the normal pattern it has been argued that the stability of the pattern and some of the details of the activation pattern requires the presence of intact afferents [41].…”

Section: Fictive Locomotionmentioning

confidence: 99%

Neural control of locomotion; Part 1: The central pattern generator from cats to humans

1998

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In the last years it has become possible to regain some locomotor activity in patients suffering from an incomplete spinal cord injury (SCI) through intense training on a treadmill. The ideas behind this approach owe much to insights derived from animal studies. Many studies showed that cats with complete spinal cord transection can recover locomotor function. These observations were at the basis of the concept of the central pattern generator (CPG) located at spinal level. The evidence for such a spinal CPG in cats and primates (including man) is reviewed in part 1, with special emphasis on some very recent developments which support the view that there is a human spinal CPG for locomotion.

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How detailed is the central pattern generation for locomotion?

Cited by 229 publications

References 11 publications

Timing factors in the coordination of speech movements

Timing factors in the coordination of speech movements

Organization of mammalian locomotor rhythm and pattern generation

Neural control of locomotion; Part 1: The central pattern generator from cats to humans

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