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Peripheral multidendritic sensory neurons are necessary for rhythmic locomotion behavior in Drosophila larvae

Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, CA 94143, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 04/2007; 104(12):5199-204. DOI: 10.1073/pnas.0700895104
Source: PubMed

ABSTRACT From breathing to walking, rhythmic movements encompass physiological processes important across the entire animal kingdom. It is thought by many that the generation of rhythmic behavior is operated by a central pattern generator (CPG) and does not require peripheral sensory input. Sensory feedback is, however, required to modify or coordinate the motor activity in response to the circumstances of actual movement. In contrast to this notion, we report here that sensory input is necessary for the generation of Drosophila larval locomotion, a form of rhythmic behavior. Blockage of all peripheral sensory inputs resulted in cessation of larval crawling. By conditionally silencing various subsets of larval peripheral sensory neurons, we identified the multiple dendritic (MD) neurons as the neurons essential for the generation of rhythmic peristaltic locomotion. By recording the locomotive motor activities, we further demonstrate that removal of MD neuron input disrupted rhythmic motor firing pattern in a way that prolonged the stereotyped segmental motor firing duration and prevented the propagation of posterior to anterior segmental motor firing. These findings reveal that MD sensory neuron input is a necessary component in the neural circuitry that generates larval locomotion.

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    • "But does each class of Md neurons respond to different sensory inputs such as touch and temperature? Class I neurons, together with bipolar dendrite neurons, function in a proprioceptive sensory feedback circuit for rhythmic locomotion (Hughes and Thomas, 2007; Song et al., 2007), whereas class IV Md neurons are involved in avoidance behavior from a very bright light (Xiang et al., 2010). Are there also designated nociceptive neurons among the various classes of Md neurons? "
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