Olfactory responses of Drosophila are encoded in the organization of projection neurons
The projection neurons (PNs), reconstructed from electron microscope (EM) images of the Drosophila olfactory system, offer a detailed view of neuronal anatomy, providing glimpses into information flow in the brain. About 150 uPNs constituting 58 glomeruli in the antennal lobe (AL) are bundled togeth...
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| Format: | Article |
| Language: | English |
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eLife Sciences Publications Ltd
2022-09-01
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| Series: | eLife |
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| Online Access: | https://elifesciences.org/articles/77748 |
| _version_ | 1811246368881115136 |
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| author | Kiri Choi Won Kyu Kim Changbong Hyeon |
| author_facet | Kiri Choi Won Kyu Kim Changbong Hyeon |
| author_sort | Kiri Choi |
| collection | DOAJ |
| description | The projection neurons (PNs), reconstructed from electron microscope (EM) images of the Drosophila olfactory system, offer a detailed view of neuronal anatomy, providing glimpses into information flow in the brain. About 150 uPNs constituting 58 glomeruli in the antennal lobe (AL) are bundled together in the axonal extension, routing the olfactory signal received at AL to mushroom body (MB) calyx and lateral horn (LH). Here we quantify the neuronal organization in terms of the inter-PN distances and examine its relationship with the odor types sensed by Drosophila. The homotypic uPNs that constitute glomeruli are tightly bundled and stereotyped in position throughout the neuropils, even though the glomerular PN organization in AL is no longer sustained in the higher brain center. Instead, odor-type dependent clusters consisting of multiple homotypes innervate the MB calyx and LH. Pheromone-encoding and hygro/thermo-sensing homotypes are spatially segregated in MB calyx, whereas two distinct clusters of food-related homotypes are found in LH in addition to the segregation of pheromone-encoding and hygro/thermo-sensing homotypes. We find that there are statistically significant associations between the spatial organization among a group of homotypic uPNs and certain stereotyped olfactory responses. Additionally, the signals from some of the tightly bundled homotypes converge to a specific group of lateral horn neurons (LHNs), which indicates that homotype (or odor type) specific integration of signals occurs at the synaptic interface between PNs and LHNs. Our findings suggest that before neural computation in the inner brain, some of the olfactory information are already encoded in the spatial organization of uPNs, illuminating that a certain degree of labeled-line strategy is at work in the Drosophila olfactory system. |
| first_indexed | 2024-04-12T14:52:31Z |
| format | Article |
| id | doaj.art-5c40cea8975b4bac8e834640cbddae37 |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-04-12T14:52:31Z |
| publishDate | 2022-09-01 |
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| series | eLife |
| spelling | doaj.art-5c40cea8975b4bac8e834640cbddae372022-12-22T03:28:22ZengeLife Sciences Publications LtdeLife2050-084X2022-09-011110.7554/eLife.77748Olfactory responses of Drosophila are encoded in the organization of projection neuronsKiri Choi0https://orcid.org/0000-0002-0156-8410Won Kyu Kim1https://orcid.org/0000-0002-6286-0925Changbong Hyeon2https://orcid.org/0000-0002-4844-7237School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Republic of KoreaSchool of Computational Sciences, Korea Institute for Advanced Study, Seoul, Republic of KoreaSchool of Computational Sciences, Korea Institute for Advanced Study, Seoul, Republic of KoreaThe projection neurons (PNs), reconstructed from electron microscope (EM) images of the Drosophila olfactory system, offer a detailed view of neuronal anatomy, providing glimpses into information flow in the brain. About 150 uPNs constituting 58 glomeruli in the antennal lobe (AL) are bundled together in the axonal extension, routing the olfactory signal received at AL to mushroom body (MB) calyx and lateral horn (LH). Here we quantify the neuronal organization in terms of the inter-PN distances and examine its relationship with the odor types sensed by Drosophila. The homotypic uPNs that constitute glomeruli are tightly bundled and stereotyped in position throughout the neuropils, even though the glomerular PN organization in AL is no longer sustained in the higher brain center. Instead, odor-type dependent clusters consisting of multiple homotypes innervate the MB calyx and LH. Pheromone-encoding and hygro/thermo-sensing homotypes are spatially segregated in MB calyx, whereas two distinct clusters of food-related homotypes are found in LH in addition to the segregation of pheromone-encoding and hygro/thermo-sensing homotypes. We find that there are statistically significant associations between the spatial organization among a group of homotypic uPNs and certain stereotyped olfactory responses. Additionally, the signals from some of the tightly bundled homotypes converge to a specific group of lateral horn neurons (LHNs), which indicates that homotype (or odor type) specific integration of signals occurs at the synaptic interface between PNs and LHNs. Our findings suggest that before neural computation in the inner brain, some of the olfactory information are already encoded in the spatial organization of uPNs, illuminating that a certain degree of labeled-line strategy is at work in the Drosophila olfactory system.https://elifesciences.org/articles/77748labeled-line designodor-type dependent arrangementsecond-order neuronsinter-neuronal organizationinformation processingsynaptic connectivity |
| spellingShingle | Kiri Choi Won Kyu Kim Changbong Hyeon Olfactory responses of Drosophila are encoded in the organization of projection neurons eLife labeled-line design odor-type dependent arrangement second-order neurons inter-neuronal organization information processing synaptic connectivity |
| title | Olfactory responses of Drosophila are encoded in the organization of projection neurons |
| title_full | Olfactory responses of Drosophila are encoded in the organization of projection neurons |
| title_fullStr | Olfactory responses of Drosophila are encoded in the organization of projection neurons |
| title_full_unstemmed | Olfactory responses of Drosophila are encoded in the organization of projection neurons |
| title_short | Olfactory responses of Drosophila are encoded in the organization of projection neurons |
| title_sort | olfactory responses of drosophila are encoded in the organization of projection neurons |
| topic | labeled-line design odor-type dependent arrangement second-order neurons inter-neuronal organization information processing synaptic connectivity |
| url | https://elifesciences.org/articles/77748 |
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