Activity of rubrospinal neurons during locomotion and scratching in the cat

Arshavsky, Yu. I.; Orlovsky, G. N.; Perret, C.

doi:10.1016/0166-4328(88)90096-4

Cited by 45 publications

(30 citation statements)

References 14 publications

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“…While it is true that somatosensory receptive fields during active movements may be somewhat different from those observed at rest (Chapman et al 1988;Ghez and Pisa 1972), the above group of observations suggest that some factors other than stimulation of somatosensory receptive field drive PTN discharges during locomotion. In fact, in decerebrated cats neurons of both reticulospinal and rubrospinal tracts display locomotion-related modulation of their activity even during fictive locomotion when the subject is motionless and thus no rhythmic afferentation is present (Arshavsky et al 1988;Perret 1976), suggesting that the spinal cord locomotor central pattern generator (CPG) plays a significant role in modulating their discharges. It is quite likely that during simple locomotion the activity of PTNs of the motor cortex also, rather than being driven by stimulation of somatosensory receptive fields, is significantly influenced by signals from the spinal locomotion CPG.…”

Section: Discussionmentioning

confidence: 99%

Pyramidal tract neurons receptive to different forelimb joints act differently during locomotion

Stout

Beloozerova

2012

Journal of Neurophysiology

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During locomotion, motor cortical neurons projecting to the pyramidal tract (PTNs) discharge in close relation to strides. How their discharges vary based on the part of the body they influence is not well understood. We addressed this question with regard to joints of the forelimb in the cat. During simple and ladder locomotion, we compared the activity of four groups of PTNs with somatosensory receptive fields involving different forelimb joints: 1) 45 PTNs receptive to movements of shoulder, 2) 30 PTNs receptive to movements of elbow, 3) 40 PTNs receptive to movements of wrist, and 4) 30 nonresponsive PTNs. In the motor cortex, a relationship exists between the location of the source of afferent input and the target for motor output. On the basis of this relationship, we inferred the forelimb joint that a PTN influences from its somatosensory receptive field. We found that different PTNs tended to discharge differently during locomotion. During simple locomotion shoulder-related PTNs were most active during late stance/early swing, and upon transition from simple to ladder locomotion they often increased activity and stride-related modulation while reducing discharge duration. Elbow-related PTNs were most active during late swing/early stance and typically did not change activity, modulation, or discharge duration on the ladder. Wrist-related PTNs were most active during swing and upon transition to the ladder often decreased activity and increased modulation while reducing discharge duration. These data suggest that during locomotion the motor cortex uses distinct mechanisms to control the shoulder, elbow, and wrist.

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Section: Discussionmentioning

confidence: 99%

Pyramidal tract neurons receptive to different forelimb joints act differently during locomotion

Stout

Beloozerova

2012

Journal of Neurophysiology

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“…33,34 Activation of red nucleus neurons and the rubrospinal tract coincides with maximal hindimb flexor electromyographical (EMG) activity and is associated with the extent of hip flexion during swing phase. [35][36][37] The lateral vestibular nucleus neurons exhibit high resting discharge rate, which establishes tonic muscle tone of paraspinal muscles extending to the lumbar cord, providing static posture and balance control. In addition, descending vestibular drive appears to be polysynaptic, stimulating extensor motor neurons during stance while triggering concurrent dynamic paraspinal responses.…”

Section: Supraspinal Contributionsmentioning

confidence: 99%

Supraspinal Control Predicts Locomotor Function and Forecasts Responsiveness to Training after Spinal Cord Injury

Field-Fote

Yang

Basso

et al. 2017

Journal of Neurotrauma

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Restoration of walking ability is an area of great interest in the rehabilitation of persons with spinal cord injury. Because many cortical, subcortical, and spinal neural centers contribute to locomotor function, it is important that intervention strategies be designed to target neural elements at all levels of the neuraxis that are important for walking ability. While to date most strategies have focused on activation of spinal circuits, more recent studies are investigating the value of engaging supraspinal circuits. Despite the apparent potential of pharmacological, biological, and genetic approaches, as yet none has proved more effective than physical therapeutic rehabilitation strategies. By making optimal use of the potential of the nervous system to respond to training, strategies can be developed that meet the unique needs of each person. To complement the development of optimal training interventions, it is valuable to have the ability to predict future walking function based on early clinical presentation, and to forecast responsiveness to training. A number of clinical prediction rules and association models based on common clinical measures have been developed with the intent, respectively, to predict future walking function based on early clinical presentation, and to delineate characteristics associated with responsiveness to training. Further, a number of variables that are correlated with walking function have been identified. Not surprisingly, most of these prediction rules, association models, and correlated variables incorporate measures of volitional lower extremity strength, illustrating the important influence of supraspinal centers in the production of walking behavior in humans.

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“…CPG feedback to its projection neuron inputs is prevalent in many rhythmic motor systems (Gillette et al, 1978; Arshavsky et al, 1988; Dubuc and Grillner, 1989; Nagy et al, 1994; Frost and Katz, 1996; Norris et al, 1996; Ezure and Tanaka, 1997; Buchanan and Einum, 2008). One shared consequence of this feedback is to impose onto the projection neurons a rhythmic activity pattern that is time-locked to the CPG-driven motor pattern.…”

Section: Discussionmentioning

confidence: 99%

“…However, whether this feedback is subject to modulation and, if so, what function it serves is unknown in most systems. In rhythmic motor systems, the activity of projection neuron inputs to central pattern generator (CPG) circuits is commonly regulated by rhythmic synaptic feedback from the activated CPG (Gillette et al, 1978; Arshavsky et al, 1988; Dubuc and Grillner, 1989; Nagy et al, 1994; Frost and Katz, 1996; Norris et al, 1996; Ezure and Tanaka, 1997; Blitz and Nusbaum, 2008; Buchanan and Einum, 2008). This rhythmic feedback causes the projection neuron activity pattern to be time-locked to the CPG-generated motor pattern.…”

Section: Introductionmentioning

confidence: 99%

Modulation of Circuit Feedback Specifies Motor Circuit Output

Blitz

Nusbaum²

2012

Journal of Neuroscience

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Bidirectional communication (i.e. feedforward and feedback pathways) between functional levels is common in neural systems, but in most systems little is known regarding the function and modifiability of the feedback pathway. We are exploring this issue in the crab (Cancer borealis) stomatogastric nervous system by examining bidirectional communication between projection neurons and their target central pattern generator (CPG) circuit neurons. Specifically, we addressed the question of whether the peptidergic POC neurons trigger a specific gastric mill (chewing) motor pattern in the stomatogastric ganglion solely by activating projection neurons, or by additionally altering the strength of CPG feedback to these projection neurons. The POC-triggered gastric mill rhythm is shaped by feedback inhibition onto projection neurons from a CPG neuron. Here we establish that POC stimulation triggers a long-lasting enhancement of feedback-mediated IPSC/Ps in the projection neurons, which persists for the same duration as POC-gastric mill rhythms. This strengthened CPG feedback appears to result from presynaptic modulation, because it also occurs in other projection neurons whose activity does not change after POC stimulation. To determine the function of this strengthened feedback synapse, we compared the influence of dynamic clamp-injected feedback IPSPs of pre- and post-POC amplitude into a pivotal projection neuron after POC stimulation. Only the post-POC amplitude IPSPs elicited the POC-triggered activity pattern in this projection neuron and enabled full expression of the POC-gastric mill rhythm. Thus, the strength of CPG feedback to projection neurons is modifiable and can be instrumental to motor pattern selection.

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Activity of rubrospinal neurons during locomotion and scratching in the cat

Cited by 45 publications

References 14 publications

Pyramidal tract neurons receptive to different forelimb joints act differently during locomotion

Pyramidal tract neurons receptive to different forelimb joints act differently during locomotion

Supraspinal Control Predicts Locomotor Function and Forecasts Responsiveness to Training after Spinal Cord Injury

Modulation of Circuit Feedback Specifies Motor Circuit Output

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