FB2026_03 , released September 17, 2026
CV Term Report
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Term peripherally synapsing interneuron ID (Ontology) FBbt:00007408 (Fly Anatomy)
Definition Neuron with its soma located anteriorly and laterally in the rind region of the mesothoracic neuromere (Phelps et al., 2021). It crosses the midline and connects via gap junctions to the giant fiber neuron at the inframedial bridge (Allen et al., 1998). It fasciculates with the posterior dorsal mesothoracic nerve, but terminates within the nerve (King and Wyman, 1980). It synapses onto neighboring motor neurons in this nerve and, unusually, these motor neurons also synapse back onto the PSI (Phelps et al., 2021). There is one of these neurons per hemisphere (Phelps et al., 2021).[ FlyBase:FBrf0035198 FlyBase:FBrf0085744 FlyBase:FBrf0247998 ]
Also Known As"PSI" ; "PSI neuron"
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VFB:FBbt_00007408
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 peripherally synapsing interneuron (all annotations which use CV term, excluding "NOT" statements)
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thoracic neuron
 |__mesothoracic neuron____
adult neuron               |
 |__adult premotor neuron__|
premotor neuron            |
 |__adult premotor neuron__|
efferent neuron            |
 |__adult efferent neuron__|
adult CNS neuron           |
 |__adult efferent neuron__|
 |__adult VNC neuron_______|
                           peripherally synapsing interneuron  6 rec.
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Is a mesothoracic neuron
adult premotor neuron
adult efferent neuron
adult VNC neuron
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VFB:FBbt_00007408