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Principles of organization and function of locomotor microcircuits in zebrafish| old_uid | 10716 |
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| title | Principles of organization and function of locomotor microcircuits in zebrafish |
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| start_date | 2012/01/20 |
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| schedule | 11h |
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| online | no |
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| details | invité par Philippe Vernier (N&D). |
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| summary | Motor behavior represents the overt expression of the processing in the brain. A salient feature of motor behavior is the orderly recruitment of motor pools and the coordination of their activity to produce movement with precise force, speed and timing. The spinal networks generate the basic locomotor pattern and also act as a processing interface to adjust their output in response to influences from the brain and sensory afferents. The natural variability in the speed of locomotion requires an orderly recruitment of motoneurons from those innervating slow to those innervating fast muscle fibers.
Our research aims at understanding the rule governing the recruitment of essential neuronal elements in the locomotor microcircuits. Thus far, our analysis has focused on the output stage by describing the mechanisms dictating the threshold of recruitment of motoneurons and a class of excitatory interneurons during swimming in adult zebrafish.
Our results show that motoneurons are organized in four pools with specific topographic locations and are incrementally recruited to produce swimming at different frequencies. The recruitment threshold is set by a combination of specific intrinsic properties of motoneurons and the strength of their synaptic currents, but does not rely on their input resistance. In contrast to motoneurons, no topographic organization was apparent for the recruitment of excitatory interneurons at different swimming frequencies.
Our findings indicate that the locomotor networks are composed of ensembles of microcircuits that are recruited sequentially to cover the full range of swimming frequencies.
Recent references:
-Büschges A, Scholz H, El Manira A. (2011) New moves in motor control. Curr Biol. 21: R513-24.
-Kyriakatos A, Mahmood R, Ausborn J, Porres CP, Büschges A, El Manira A. (2011) Initiation of locomotion in adult zebrafish. J Neurosci. 31: 8422-31.
-Gabriel JP, Ausborn J, Ampatzis K, Mahmood R, Eklöf-Ljunggren E, El Manira A. (2011) Principles governing recruitment of motoneurons during swimming in zebrafish. Nat Neurosci. 14: 93-9.
-Gabriel JP, Mahmood R, Kyriakatos A, Söll I, Hauptmann G, Calabrese RL, El Manira A. (2009) Serotonergic modulation of locomotion in zebrafish: endogenous release and synaptic mechanisms. J Neurosci. 29: 10387-95 |
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| responsibles | Secrétariat Inaf, Perignon |
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