FB2026_03 , released September 17, 2026

CV Term Report

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General Information

Term

transmedullary neuron Tm9

ID (Ontology)

FBbt:00003797 (Fly Anatomy)

Definition

Transmedullary narrow field neuron that has most of its dendritic arborization in medulla layers M2 and M3, with some extensions into M1, M4 and M5 (Gao et al., 2008; Ting et al., 2014), and presynapses in M3 (Gao et al., 2008). Its axon follows the posterior edge of its cognate medulla column (Ting et al., 2014), then crosses in the second optic chiasma and terminates in lobula layer 1 (Fischbach and Dittrich, 1989; Ting et al., 2014), where it outputs to T5 neurons (Shinomiya et al., 2014). It is a cholinergic neuron (Gao et al., 2008; Shinomiya et al., 2014). It expresses the transcription factor sim (Ozel et al., 2021). There is usually one of these cells per optic column (Nern et al., 2025).[ FlyBase:FBrf0049410 FlyBase:FBrf0204652 FlyBase:FBrf0206213 FlyBase:FBrf0224196 FlyBase:FBrf0225094 FlyBase:FBrf0247762 FlyBase:FBrf0262545 ]

Also Known As

"Tm9"

Comment

Neurotransmitter was assessed using a cha-GAL4DBD driver (Gao et al., 2008), single-cell transcript profiling and immunohistochemistry (Shinomiya et al., 2014). Connectivity in the lobula was assessed by serial section electron microscopy of a single column (Shinomiya et al., 2014).

Links to External Ontologies

VFB:FBbt_00003797

Annotations

Records annotated with this term OR any of its CHILD TERMS

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Direct annotations: records annotated with this exact term (child terms are NOT included)

Data Class	Field	Direct annotations
Alleles (FBal)	PHENOTYPE_MANIFEST_IN
Insertions (FBti)	EXPRESSION_STAGE_TISSUE_POSITION
Insertions (FBti)	PHENOTYPE_MANIFEST_IN

Full annotation statements including this term (annotations to child terms are NOT included), and relevant FlyBase records

Full annotation statements	Relevant FlyBase reports
Full annotation statements	Alleles	Split System Combinations	Genes		Insertions	Constructs
transmedullary neuron Tm9 (all annotations which use CV term, excluding "NOT" statements)
transmedullary neuron Tm9 \| P-stage		--	--	--		--

Spanning Tree (Parents/Children)

transmedullary neuron
 |__narrow field transmedullary neuron_____
cholinergic neuron                         |
 |__adult cholinergic neuron_______________|
adult neuron                               |
 |__adult cholinergic neuron_______________|
secondary neuron                           |
 |__Notch ON hemilineage secondary neuron__|
Notch ON hemilineage neuron                |
 |__Notch ON hemilineage secondary neuron__|
optic lobe narrow field columnar neuron    |
 |__narrow field transmedullary neuron_____|
                                           transmedullary neuron Tm9  50 rec.
                                            |__transmedullary neuron Tm9a 1 rec.
                                            |__transmedullary neuron Tm9b 1 rec.

Spanning Tree View Settings
Parents/Children View Depth	Show hierarchy levels: for parents, for children
Relationships
Is a	narrow field transmedullary neuron Notch ON hemilineage secondary neuron adult cholinergic neuron
Develops from	immature transmedullary neuron Tm9
Part of
Synonyms & Secondary IDs
Synonyms
	"Tm9" EXACT VFB_SYMBOL[ FlyBase:FBrf0247762 ]
Secondary IDs

External Crossreferences & Linkouts
	FlyBrain_NDB:10163 VFB:FBbt_00003797