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Neuroscience
Cluster Scientific Retreat |
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Postdoctoral Fellow, Department of Neurobiology How do spinal interneurons control locomotion? The basic features of locomotor behavior are generated by neural circuits that reside in the spinal cord. These circuits are composed of interneurons that can be divided into broad classes based on their developmental origin. We tested the function of one of these neuron classes, the V2a neurons, by ablating them in transgenic mice. Mice lacking V2a neurons exhibit defective coordination between limbs on the left and right sides of their bodies, resulting in a hopping gait. Using mice in which the axons and processes of V2a neurons are fluorescently labeled, we showed that the ipsilaterally projecting V2a neurons make synaptic contacts onto commissural neurons that inhibit the opposite side of the cord during locomotion, ensuring normal alternation of stepping movements. Interestingly, V2a neurons are only required for an alternating gait at high locomotor speeds. Thus, the speed of movement dictates which neurons are used to generate locomotor behavior. 09/03/2009 |