FB2026_03 , released September 17, 2026
CV Term Report
Help Close All Open All
General Information
Term period-positive median segmental interneuron ID (Ontology) FBbt:00111047 (Fly Anatomy)
Definition Glutamatergic, period-expressing, interneuron of the larval ventral nerve cord whose soma is located near the ventral midline of each segment (Kohsaka et al., 2014; Kohsaka et al., 2019). Its axon projects dorsally toward the dorsal midline, turns laterally and extends toward the lateral edge of the neuropil; it then makes a loop around the DL fascicle and projects back medially (Kohsaka et al., 2014; Kohsaka et al., 2019). Its terminals are mainly found in the dorsal neuropil region of the same segment as its soma (Kohsaka et al., 2014). There are around 10 of these interneurons in each hemineuromere (Kohsaka et al., 2014; Kohsaka et al., 2019), which develop from the NB2-1 neuroblast (Kohsaka et al., 2019; Mark et al., 2021).[ FlyBase:FBrf0226895 FlyBase:FBrf0242656 FlyBase:FBrf0249021 ]
Also Known As"looper neuron" ; "PMSI neuron"
CommentKohsaka et al. (2014) and Kohsaka et al. (2019) claim there are only 10 PMSI neurons per hemineuromere (A02a-j). McNamee et al. (2016) - FBrf0232247 and Mark et al. (2021) seem to consider all lineage 2 neurons to be PMSIs (despite some lacking the characteristic dorsal loop).
Links to External Ontologies
VFB:FBbt_00111047
Annotations
Records annotated with this term OR any of its CHILD TERMS

Choose a record type to view annotations for this term and its child terms. Direct annotations and full annotation statements below also provide HitList buttons.

    • Results list data from multiple species. Choose a record type above to open its HitList.
Direct annotations: records annotated with this exact term (child terms are NOT included)
There are no annotations using this term.
show Full annotation statements including this term (annotations to child terms are NOT included), and relevant FlyBase records
 Full annotation statements 
Relevant FlyBase reports
 Constructs
 period-positive median segmental interneuron (all annotations which use CV term, excluding "NOT" statements)
Spanning Tree (Parents/Children)
Only view relationship:
Vocabulary search 
larval neuron
 |__larval premotor neuron_____________
 |__larval glutamatergic neuron________|
larval central nervous system          |
 |__larval ventral nerve cord__________|
 |__larval interneuron_________________|
ventral nerve cord                     |
 |__larval ventral nerve cord__________|
interneuron                            |
 |__larval interneuron_________________|
ganglion                               |
 |__larval ventral nerve cord__________|
ventral ectoderm derivative            |
 |__larval ventral nerve cord__________|
NB2-1 lineage primary neuron           |
 |__lineage NB2-1 primary interneuron__|
premotor neuron                        |
 |__larval premotor neuron_____________|
primary interneuron                    |
 |__lineage NB2-1 primary interneuron__|
larval CNS neuron                      |
 |__larval interneuron_________________|
glutamatergic neuron                   |
 |__larval glutamatergic neuron________|
                                       period-positive median segmental interneuron  7 rec.
                                        |__larval A02a neuron 2 rec.
                                        |   |__larval abdominal 1 A02a neuron
                                        |   |__larval abdominal 3 A02a neuron
                                        |__larval A02b neuron 2 rec.
                                        |   |__larval abdominal 1 A02b neuron
                                        |   |__larval abdominal 2 A02b neuron
                                        |   |__larval abdominal 3 A02b neuron
                                        |__larval A02c neuron
                                        |   |__larval abdominal 1 A02c neuron
                                        |__larval A02d neuron
                                        |   |__larval abdominal 1 A02d neuron
                                        |__larval A02e neuron
                                        |   |__larval abdominal 1 A02e neuron
                                        |__larval A02f neuron
                                        |   |__larval abdominal 1 A02f neuron
                                        |__larval A02g neuron
                                        |   |__larval abdominal 1 A02g neuron
                                        |__larval A02h neuron
                                        |   |__larval abdominal 1 A02h neuron
                                        |__larval A02i neuron
                                        |   |__larval abdominal 1 A02i neuron
                                        |__larval A02j neuron
                                            |__larval abdominal 1 A02j neuron
                                            |__larval abdominal 2 A02j neuron
                                            |__larval abdominal 3 A02j neuron
Spanning Tree View Settings
Parents/Children
View Depth
Show hierarchy levels: for parents, for children
hide Relationships
Is a lineage NB2-1 primary interneuron
larval premotor neuron
larval interneuron
larval glutamatergic neuron
Part of larval ventral nerve cord
hide Synonyms & Secondary IDs
Synonyms
Secondary IDs
hide External Crossreferences & Linkouts
VFB:FBbt_00111047