Initiation of locomotion in lampreys

Dubuc, Réjean; Brocard, Frédéric; Antri, Myriam; Fénelon, Karine; Gariépy, Jean François; Smetana, Roy; Ménard, Ariane; Ray, Didier Le; Prisco, Gonzalo Viana Di; Pearlstein, Édouard; Sirota, Mikhail G.; Derjean, Dominique; St-Pierre, Melissa; Zielinski, Barbara S.; Auclair, François; Veilleux, Danielle

doi:10.1016/j.brainresrev.2007.07.016

Cited by 149 publications

(171 citation statements)

References 76 publications

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“…The same effect can also be achieved by simulating the effect of applying glutamate on the spinal cord, which is analogous to the reticulospinal activation. Each of the left and right locomotor command regions in mesencephalon (MLR) exert a bilateral symmetric excitatory effect on the reticulospinal neurons (26,42), which in turn, drives the CPG; therefore, each side can induce symmetric locomotion. This provides the rationale for lumping MLR and the reticulospinal level into one (see Fig.…”

Section: Discussionmentioning

confidence: 99%

Simple cellular and network control principles govern complex patterns of motor behavior

Kozlov

Huss²,

Lansner³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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The vertebrate central nervous system is organized in modules that independently execute sophisticated tasks. Such modules are flexibly controlled and operate with a considerable degree of autonomy. One example is locomotion generated by spinal central pattern generator networks (CPGs) that shape the detailed motor output. The level of activity is controlled from brainstem locomotor command centers, which in turn, are under the control of the basal ganglia. By using a biophysically detailed, full-scale computational model of the lamprey CPG (10,000 neurons) and its brainstem/forebrain control, we demonstrate general control principles that can adapt the network to different demands. Forward or backward locomotion and steering can be flexibly controlled by local synaptic effects limited to only the very rostral part of the network. Variability in response properties within each neuronal population is an essential feature and assures a constant phase delay along the cord for different locomotor speeds.basal ganglia ͉ brainstem ͉ computational model ͉ lamprey ͉ spinal CPG V ertebrate behavior depends on different sets of neuronal networks specialized to coordinate different motor tasks like locomotion, breathing, and the expression of emotions (1-5). The activity of these networks is governed by brainstem command centers that are, in turn, under the control of the basal ganglia (1, 2). Although the critical role of these networks is well established, their intrinsic mode of operation has, for the most part, remained enigmatic. The lamprey nervous system provides one of the few examples in which detailed knowledge is available, not only of the different types of the participating neurons, but also their membrane properties and synaptic connectivity, particularly with regard to the spinal network (6, 7). Even with this knowledge at hand, it is very difficult, if not impossible, to establish, without the help of modeling, whether the experimental data available are actually sufficient to account for the dynamic operation of the networkand enable exploration of the particular role of different cellular and synaptic components to make predictions of their functional role. To achieve this, we report here a biophysically realistic model of the locomotor network and its control from the brain. The spinal network is composed of excitatory and inhibitory model neurons that, in considerable detail, behave as their biological counterparts. It proved to be important to introduce within each pool of model neurons the known biological variability in neuronal size and membrane properties. Thanks to recent developments in computer technology, we have been able to make a full-scale model of the network with 100 model neurons per segment, each of the Hodgkin-Huxley type-altogether 10,000 neurons connected via 760,000 synapses in the 100 segments. We represent the brainstem command system, as well as the forebrain control from the basal ganglia with an additional 3,500 neurons. Simulations limited to subsamples of neurons have previou...

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Section: Discussionmentioning

confidence: 99%

Simple cellular and network control principles govern complex patterns of motor behavior

Kozlov

Huss²,

Lansner³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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“…Yet, the commands for initiation and gait selection may originate in different supraspinal structures. The most important neuronal structure that has been implicated in these functions is a region in the midbrain named the mesencephalic locomotor region or MLR 7,8,9 .…”

Section: Introductionmentioning

confidence: 99%

“…Analogues of MLR have been observed in many vertebrates including fish, rodents, primates and humans 8,9,11,12 but with conflicting results as to its anatomical location. In addition to CnF the more ventrally located pedunculopontine nucleus (PPN) has been implicated.…”

Section: Introductionmentioning

confidence: 99%

Midbrain circuits that set locomotor speed and gait selection

Caggiano¹,

Leiras²,

Goñi-Erro³

et al. 2018

Nature

335

511

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Summary Locomotion is a fundamental motor function common to the animal kingdom. It is executed episodically and adapted to behavioural needs including exploration, requiring slow locomotion, and escaping behaviour, necessitating faster speeds. The control of these functions originates in brainstem structures although the neuronal substrate(s) supporting them are debated. Here, we show in mice that speed/gait selection are controlled by glutamatergic excitatory neurons (GlutNs) segregated in two distinct midbrain nuclei: the Cuneiform Nucleus (CnF) and the Pedunculopontine Nucleus (PPN). GlutNs in each of those two regions are sufficient for controlling slower alternating locomotor behavior but only GlutNs in the CnF are necessary for high-speed synchronous locomotion. Additionally, PPN- and CnF-GlutNs activation dynamics and their input and output connectivity matrices support explorative and escape locomotion, respectively. Our results identify dual regions in the midbrain that act in common to select context dependent locomotor behaviours.

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“…The mesencephalic locomotor region (MLR) is well conserved throughout vertebrate phyla (Grillner et al, 1998;Dubuc, 2009;Dubuc et al, 2008). It produces muscle synergies underlying different forms of locomotion such as swimming in cyclostomes and fishes, flying in birds, and stepping in tetrapods, including mammals.…”

Section: Introductionmentioning

confidence: 99%