El Manira Laboratory
The goal of our research is to decipher the organizational logic together with the intricate coding and processing that allow the spinal network to produce locomotor movements with varying speed and force.
The goal of our research is to decipher the organizational logic together with the intricate coding and processing that allow the spinal network to produce locomotor movements with varying speed and force. To achieve this, our laboratory has pioneered the use of the adult zebrafish, which lends itself to a detailed experimental analysis using a variety of state-of-the-art tools.
Thus far, our studies have revealed the organization and pattern of recruitment of motoneurons and excitatory interneurons during swimming. Our recent results show that motoneurons are divided into four distinct pools with a somatotopic organization in the motor column depending on the type of muscle they innervate. These motoneuron pools represent discrete modules that are deployed incrementally with increasing swimming speed.
In addition, we have identified a class of excitatory interneurons as the substrate for the excitatory drive that endows the spinal network with the capacity to generate swimming.
Finally, we have uncovered a novel principle of organization of the spinal locomotor network consisting of ensembles of microcircuits that act as an intrinsic gearshift. Each microcircuit encompasses a subset of motoneurons and excitatory interneurons that are incrementally recruited to increase the swimming speed.
Thus, novel insights into the principles governing locomotor microcircuits organization and function are beginning to emerge from our studies that may have general implications beyond the study of circuits for motor behavior.
Principles governing recruitment of neurons during locomotion. At slow swimming speeds only slow microcircuits activating slow muscles are recruited. Fast microcircuits are deployed with increased speed and activate fast muscles.
Motor neurons control locomotor circuit function retrogradely via gap junctions.
Song J, Ampatzis K, Björnfors ER, El Manira A
Nature 2016 Jan;529(7586):399-402
Separate microcircuit modules of distinct v2a interneurons and motoneurons control the speed of locomotion.
Ampatzis K, Song J, Ausborn J, El Manira A
Neuron 2014 Aug;83(4):934-43
Optogenetic activation of excitatory premotor interneurons is sufficient to generate coordinated locomotor activity in larval zebrafish.
Ljunggren EE, Haupt S, Ausborn J, Ampatzis K, El Manira A
J. Neurosci. 2014 Jan;34(1):134-9
Decoding the rules of recruitment of excitatory interneurons in the adult zebrafish locomotor network.
Ausborn J, Mahmood R, El Manira A
Proc. Natl. Acad. Sci. U.S.A. 2012 Dec;109(52):E3631-9
Origin of excitation underlying locomotion in the spinal circuit of zebrafish.
Eklöf-Ljunggren E, Haupt S, Ausborn J, Dehnisch I, Uhlén P, Higashijima S, et al
Proc. Natl. Acad. Sci. U.S.A. 2012 Apr;109(14):5511-6