Phasic modulation of reticulospinal neurones during fictive locomotion and other types of spinal motor activity in lamprey

Kasicki, S; Grillner, Sten; Ohta, Yoshihiro; Dubuc, Réjean; Brodin, Lennart

doi:10.1016/0006-8993(89)90363-6

Cited by 98 publications

(75 citation statements)

References 26 publications

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“…Patterned synaptic feedback from central pattern-generating circuits to their modulatory inputs is well documented in many motor systems (Weeks, 1981;Robertson and Moulins, 1984;Nusbaum and Kristan, 1986;Dubuc and Grillner, 1989;Kasicki et al, 1989;Nagy et al, 1994;Frost and Katz, 1996;Perrins and Weiss, 1996;Deliagina et al, 2000). In the few previous studies that aimed to understand the function of this rhythmic feedback, the focus was generally restricted to potential consequences for the circuit responsible for this feedback (Weeks, 1981;Kasicki et al, 1989;Deliagina et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

“…In the few previous studies that aimed to understand the function of this rhythmic feedback, the focus was generally restricted to potential consequences for the circuit responsible for this feedback (Weeks, 1981;Kasicki et al, 1989;Deliagina et al, 2000). The results of these studies were Figure 6.…”

Section: Discussionmentioning

confidence: 99%

“…Projection neurons that activate rhythmically active neuronal circuits commonly switch from a tonic to rhythmic activity pattern once their target circuit is activated as a result of feedback they receive from that circuit (Weeks, 1981;Dubuc and Grillner, 1989;Kasicki et al, 1989;Frost and Katz, 1996;Perrins and Weiss, 1996;Deliagina et al, 2000). Despite this rhythmic activity pattern, tonic stimulation of these projection neurons is often sufficient to elicit rhythmic activity from the target circuit, suggesting that these inputs provide no timing cues to the activated circuit.…”

Section: Introductionmentioning

confidence: 99%

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Intercircuit Control via Rhythmic Regulation of Projection Neuron Activity

Wood¹,

Manor²,

Nadim³

et al. 2004

J. Neurosci.

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Synaptic feedback from rhythmically active neuronal circuits commonly causes their descending inputs to exhibit the rhythmic activity pattern generated by that circuit. In most cases, however, the function of this rhythmic feedback is unknown. In fact, generally these inputs can still activate the target circuit when driven in a tonic activity pattern. We are using the crab stomatogastric nervous system (STNS) to test the hypothesis that the neuronal circuit-mediated rhythmic activity pattern in projection neurons contributes to intercircuit regulation. The crab STNS contains an identified projection neuron, modulatory commissural neuron 1 (MCN1), whose tonic stimulation activates and modulates the gastric mill (chewing) and pyloric (filtering of chewed food) motor circuits in the stomatogastric ganglion (STG). During tonic stimulation of MCN1, the pyloric circuit regulates both gastric mill cycle frequency and gastropyloric coordination via a direct synapse onto a gastric mill neuron in the STG. However, when MCN1 is spontaneously active, it has a pyloric-timed activity pattern attributable to synaptic input from the pyloric circuit. This pyloric-timed activity in MCN1 provides the pyloric circuit with a second pathway for regulating the gastric mill rhythm. At these times, the direct STG synapse from the pyloric circuit to the gastric mill circuit is not necessary for pyloric regulation of the gastric mill rhythm. However, in the intact system, these two pathways play complementary roles in this intercircuit regulation. Thus, one role for rhythmicity in modulatory projection neurons is to enable them to mediate the interactions between distinct but related neuronal circuits.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Intercircuit Control via Rhythmic Regulation of Projection Neuron Activity

Wood¹,

Manor²,

Nadim³

et al. 2004

J. Neurosci.

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“…RS cells have been shown to be rhythmically active during locomotion in several animal species, including mammals (Orlovsky, 1970a,b;Drew et al, 1986) and lampreys (Kasicki and Grillner, 1986;Dubuc and Grillner, 1989;Kasicki et al, 1989;Vinay and Grillner, 1992). Orlovsky proposed in the early 1970s that the rhythmic modulation in cat RS cells originated from the spinal locomotor networks (Orlovsky, 1970a).…”

Section: Contribution Of Spinal Cord Inputsmentioning

confidence: 99%

The Contribution of Synaptic Inputs to Sustained Depolarizations in Reticulospinal Neurons

2009

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Sensory stimulation elicits sustained depolarizations in lamprey reticulospinal (RS) cells for which intrinsic properties were shown to play a crucial role. The depolarizations last up to minutes, and we tested whether the intrinsic properties required the cooperation of synaptic inputs to maintain RS cells depolarized for such long periods of time. Ascending spinal inputs to RS cells were reversibly blocked by applying xylocaine over the rostral spinal cord segments. The duration of the sustained depolarizations was markedly reduced. The membrane potential oscillations in tune with locomotor activity that were present under control condition were also abolished. The contribution of excitatory glutamatergic inputs was then assessed by applying CNQX and AP-5 over one of two simultaneously recorded homologous RS cells on each side of the brainstem. The level of sensory-evoked depolarization decreased significantly in the cell exposed to the antagonists compared with the other RS cell monitored as a control. In contrast, local application of glycine only produced a transient membrane potential hyperpolarization with a marked reduction in the amplitude of membrane potential oscillations. Locally applied strychnine did not change the duration of the sustained depolarizations, suggesting that mechanisms other than glycinergic inhibition are involved in ending the sustained depolarizations in RS cells. It is concluded that excitatory glutamatergic inputs, including ascending spinal feedback, cooperate with intrinsic properties of RS cells to maintain the cells depolarized for prolonged periods, sustaining long bouts of escape swimming.

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“…One can expect that vestibular reflexes caused by external factors and by undulatory head movements interact. Vestibular reflexes can also be rhythmically modulated by the spinal locomotor CPG by two routes: 1) the RS neurons themselves are modulated by efference copy signals (Kasicki et al 1989) and 2) the efficacy of vestibular input to these neurons is rhythmically gated (Bussiéres and Dubuc 1992;Pflieger and Dubuc 2004). To study this problem, recording of the activity of RS neurons during swimming and correlation of this activity with active and passive head movements should be carried out.…”

Section: Functional Role Of Group 1 Neuronsmentioning

confidence: 99%

Responses of Reticulospinal Neurons in the Lamprey to Lateral Turns

Karayannidou

Zelenin²,

Orlovsky³

et al. 2007

Journal of Neurophysiology

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Karayannidou A, Zelenin PV, Orlovsky GN, Deliagina TG. Responses of reticulospinal neurons in the lamprey to lateral turns. J Neurophysiol 97: 512-521, 2007. First published November 1, 2006; doi:10.1152/jn.00912.2006. When swimming, the lamprey maintains a definite orientation of its body in the vertical planes, in relation to the gravity vector, as the result of postural vestibular reflexes. Do the vestibular-driven mechanisms also play a role in the control of the direction of swimming in the horizontal (yaw) plane, in which the gravity cannot be used as a reference direction? In the present study, we addressed this question by recording responses to lateral turns in reticulospinal (RS) neurons mediating vestibulospinal reflexes. In intact lampreys, the activity of axons of RS neurons was recorded in the spinal cord by implanted electrodes. Vestibular stimulation was performed by periodical turns of the animal in the yaw plane (60°p eak to peak). It was found that the majority of responding RS neurons were activated by the contralateral turn. By removing one labyrinth, we found that yaw responses in RS neurons were driven mainly by input from the contralateral labyrinth. We suggest that these neurons, when activated by the contralateral turn, will elicit the ipsilateral turn and thus will compensate for perturbations of the rectilinear swimming caused by external factors. It is also known that unilateral eye illumination elicits a contralateral turn in the yaw plane (negative phototaxis). We found that a portion of RS neurons were activated by the contralateral eye illumination. By eliciting an ipsilateral turn, these neurons could mediate the negative phototaxis.

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Phasic modulation of reticulospinal neurones during fictive locomotion and other types of spinal motor activity in lamprey

Cited by 98 publications

References 26 publications

Intercircuit Control via Rhythmic Regulation of Projection Neuron Activity

Intercircuit Control via Rhythmic Regulation of Projection Neuron Activity

The Contribution of Synaptic Inputs to Sustained Depolarizations in Reticulospinal Neurons

Responses of Reticulospinal Neurons in the Lamprey to Lateral Turns

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