Circuit diagram of the lateral horn

Schematic overview of olfactory and multimodal input to the adult lateral horn (LH) and the major target neuropils of LH output neurons, based on Frechter et al. (2019). Panel A shows the four antennal-lobe tracts (mALT, mlALT, tALT, lALT) by which projection neurons (PNs) reach the LH. Panel B groups PN axonal arbours in the LH by presumptive sensory modality: excitatory uniglomerular olfactory, inhibitory olfactory, multiglomerular olfactory, multiglomerular + gustatory, gustatory, mechanosensory, thermosensory, and neuromodulatory. Panel E shows the major (AVLP, PVLP, SLP, SIP, SMP) and minor (LH, MB calyx, SCL, IB, ICL, SPS, CRE) target neuropils of core LH output neurons (LHONs). Click a labelled element to open the corresponding term in Virtual Fly Brain.
Categories:
<!-- Panel B: PN classes by presumptive sensory modality (4 cols × 2 rows of thumbnails) -->
<area shape="rect" coords="799,49,1174,228" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00007383" title="excitatory uniglomerular olfactory PN">
<area shape="rect" coords="1190,49,1565,228" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00100224" title="inhibitory olfactory PN (lateral antennal lobe tract PN)">
<area shape="rect" coords="1581,49,1956,228" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00007384" title="multiglomerular olfactory PN">
<area shape="rect" coords="1972,49,2347,228" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00007384" title="multiglomerular olfactory + gustatory PN">

<area shape="rect" coords="799,244,1174,424" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00047946" title="gustatory projection neuron">
<area shape="rect" coords="1190,244,1565,424" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00052606" title="mechanosensory projection neuron">
<area shape="rect" coords="1581,244,1956,424" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00047228" title="thermosensory projection neuron">
<area shape="rect" coords="1972,244,2347,424" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00007422" title="neuromodulatory projection neuron (antennal lobe PN)">

<!-- Panel C: LHN reconstructions overview (whole brain renderings) -->
<area shape="rect" coords="65,489,815,913" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00049286" title="adult lateral horn output neuron (LHON) — all reconstructions">
<area shape="rect" coords="831,489,1581,913" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00049286" title="core LHONs">
<area shape="rect" coords="1597,489,2347,913" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00049285" title="adult lateral horn local neuron (LHLN)">

<!-- Panel E: target neuropils. Major (left brain rendering) and minor (right brain rendering). -->
<!-- Major target neuropils -->
<area shape="rect" coords="619,2983,880,3097" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00040043" title="anterior ventrolateral protocerebrum (AVLP)">
<area shape="rect" coords="619,3097,880,3203" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00040042" title="posterior ventrolateral protocerebrum (PVLP)">
<area shape="rect" coords="619,3203,880,3301" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00007054" title="superior lateral protocerebrum (SLP)">
<area shape="rect" coords="619,3301,880,3366" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00045032" title="superior intermediate protocerebrum (SIP)">
<area shape="rect" coords="619,3366,880,3423" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00007055" title="superior medial protocerebrum (SMP)">

<!-- Minor target neuropils -->
<area shape="rect" coords="1467,2983,1760,3048" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00007053" title="lateral horn (LH)">
<area shape="rect" coords="1467,3048,1760,3105" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00003685" title="mushroom body calyx (MB_CA)">
<area shape="rect" coords="1467,3105,1760,3162" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00040048" title="superior clamp (SCL)">
<area shape="rect" coords="1467,3162,1760,3219" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00040050" title="inferior bridge (IB)">
<area shape="rect" coords="1467,3219,1760,3276" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00040049" title="inferior clamp (ICL)">
<area shape="rect" coords="1467,3276,1760,3334" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00045040" title="superior posterior slope (SPS)">
<area shape="rect" coords="1467,3334,1760,3391" target="_blank" href="https://v2.virtualflybrain.org/org.geppetto.frontend/geppetto?i=VFB_00101567&id=FBbt_00045037" title="crepine (CRE)">

https://doi.org/10.7554/eLife.44590

Figure reproduced under CC-BY 4.0 from Frechter S, Bates AS, Tootoonian S, Dolan M-J, Manton J, Jamasb AR, Kohl J, Bock D, Jefferis G (2019). Functional and anatomical specificity in a higher olfactory centre. eLife 8:e44590.


Last modified May 7, 2026: Add lateral horn circuit diagram (Frechter et al. 2019) (3603751)