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The wiring diagram of a glomerular olfactory system.

Berck ME, Khandelwal A, Claus L, Hernandez-Nunez L, Si G, Tabone CJ, Li F, Truman JW, Fetter RD, Louis M, Samuel AD, Cardona A - Elife (2016)

Bottom Line: We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn.A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse.This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Harvard University, Cambridge, United States.

ABSTRACT
The sense of smell enables animals to react to long-distance cues according to learned and innate valences. Here, we have mapped with electron microscopy the complete wiring diagram of the Drosophila larval antennal lobe, an olfactory neuropil similar to the vertebrate olfactory bulb. We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn. A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse. LN-LN synaptic connections putatively implement a bistable gain control mechanism that either computes odor saliency through panglomerular inhibition, or allows some glomeruli to respond to faint aversive odors in the presence of strong appetitive odors. This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior.

No MeSH data available.


Related in: MedlinePlus

EM-reconstructed arbor of the descending neuron.Renderings of the left antennal lobe, posterior view. This identified neuron exists in the left and right antennal lobes, presenting similar morphology and connectivity in the right antennal lobe. Broad LNs and uPNs are shown for reference. Scale bar: a cell body measures about 4 micrometers in diameter.DOI:http://dx.doi.org/10.7554/eLife.14859.018
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fig5s1: EM-reconstructed arbor of the descending neuron.Renderings of the left antennal lobe, posterior view. This identified neuron exists in the left and right antennal lobes, presenting similar morphology and connectivity in the right antennal lobe. Broad LNs and uPNs are shown for reference. Scale bar: a cell body measures about 4 micrometers in diameter.DOI:http://dx.doi.org/10.7554/eLife.14859.018

Mentions: In the mammalian olfactory bulb, descending inputs from the brain target granule cells (the multiglomerular inhibitory LNs), shaping the level of inhibition (Balu et al., 2007). In addition to descending neuromodulatory neurons (CSD; Figure 5a), in the larva we found a descending neuron (Figure 5—figure supplement 1) that targets specific mPNs and LNs (Figure 4—figure supplement 2). In addition to other mPNs, this descending neuron targets the two mPNs that we postulate are aversive (mPNs A3 and B3). Together with the axo-axonic inputs it receives from 45a ORN (an aversive ORN, [Bellmann et al., 2010; Hernandez-Nunez et al., 2015]), this descending neuron is associated with the processing of aversive stimuli. Additional descending neurons affecting PNs and LNs might exist but were beyond the scope of this study, where we focused on neurons directly synapsing with ORNs.


The wiring diagram of a glomerular olfactory system.

Berck ME, Khandelwal A, Claus L, Hernandez-Nunez L, Si G, Tabone CJ, Li F, Truman JW, Fetter RD, Louis M, Samuel AD, Cardona A - Elife (2016)

EM-reconstructed arbor of the descending neuron.Renderings of the left antennal lobe, posterior view. This identified neuron exists in the left and right antennal lobes, presenting similar morphology and connectivity in the right antennal lobe. Broad LNs and uPNs are shown for reference. Scale bar: a cell body measures about 4 micrometers in diameter.DOI:http://dx.doi.org/10.7554/eLife.14859.018
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4930330&req=5

fig5s1: EM-reconstructed arbor of the descending neuron.Renderings of the left antennal lobe, posterior view. This identified neuron exists in the left and right antennal lobes, presenting similar morphology and connectivity in the right antennal lobe. Broad LNs and uPNs are shown for reference. Scale bar: a cell body measures about 4 micrometers in diameter.DOI:http://dx.doi.org/10.7554/eLife.14859.018
Mentions: In the mammalian olfactory bulb, descending inputs from the brain target granule cells (the multiglomerular inhibitory LNs), shaping the level of inhibition (Balu et al., 2007). In addition to descending neuromodulatory neurons (CSD; Figure 5a), in the larva we found a descending neuron (Figure 5—figure supplement 1) that targets specific mPNs and LNs (Figure 4—figure supplement 2). In addition to other mPNs, this descending neuron targets the two mPNs that we postulate are aversive (mPNs A3 and B3). Together with the axo-axonic inputs it receives from 45a ORN (an aversive ORN, [Bellmann et al., 2010; Hernandez-Nunez et al., 2015]), this descending neuron is associated with the processing of aversive stimuli. Additional descending neurons affecting PNs and LNs might exist but were beyond the scope of this study, where we focused on neurons directly synapsing with ORNs.

Bottom Line: We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn.A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse.This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Harvard University, Cambridge, United States.

ABSTRACT
The sense of smell enables animals to react to long-distance cues according to learned and innate valences. Here, we have mapped with electron microscopy the complete wiring diagram of the Drosophila larval antennal lobe, an olfactory neuropil similar to the vertebrate olfactory bulb. We found a canonical circuit with uniglomerular projection neurons (uPNs) relaying gain-controlled ORN activity to the mushroom body and the lateral horn. A second, parallel circuit with multiglomerular projection neurons (mPNs) and hierarchically connected local neurons (LNs) selectively integrates multiple ORN signals already at the first synapse. LN-LN synaptic connections putatively implement a bistable gain control mechanism that either computes odor saliency through panglomerular inhibition, or allows some glomeruli to respond to faint aversive odors in the presence of strong appetitive odors. This complete wiring diagram will support experimental and theoretical studies towards bridging the gap between circuits and behavior.

No MeSH data available.


Related in: MedlinePlus