Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds.
As odor concentration increases, primary olfactory network representations expand in spatial distribution, temporal complexity and duration. However, the direct relationship between concentration dependent odor representations and the psychophysical thresholds of detection and discrimination is poor...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2016-01-01
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| Series: | Frontiers in Cellular Neuroscience |
| Subjects: | |
| Online Access: | http://journal.frontiersin.org/Journal/10.3389/fncel.2015.00515/full |
| _version_ | 1818339746518138880 |
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| author | Kevin C Daly Samual P Bradley Philip D Chapman Erich M Staudacher Regina eTiede Regina eTiede Joachim eSchachtner |
| author_facet | Kevin C Daly Samual P Bradley Philip D Chapman Erich M Staudacher Regina eTiede Regina eTiede Joachim eSchachtner |
| author_sort | Kevin C Daly |
| collection | DOAJ |
| description | As odor concentration increases, primary olfactory network representations expand in spatial distribution, temporal complexity and duration. However, the direct relationship between concentration dependent odor representations and the psychophysical thresholds of detection and discrimination is poorly understood. This relationship is absolutely critical as thresholds signify transition points whereby representations become meaningful to the organism. Here, we matched stimulus protocols for psychophysical assays and intracellular recordings of antennal lobe projection neurons in the moth Manduca sexta to directly compare psychophysical thresholds and the output representations they elicit. We first behaviorally identified odor detection and discrimination thresholds across an odor dilution series for a panel of structurally similar odors. We then characterized spatiotemporal spiking patterns across a population of individually filled and identified antennal lobe projection neurons in response to those odors at concentrations below, at, and above identified thresholds. Using spatial and spatiotemporal based analyses we observed that each stimulus produced unique representations, even at sub-threshold concentrations. Mean response latency did not decrease and the percent glomerular activation did not increase with concentration until undiluted odor. Furthermore, correlations between spatial patterns for odor decreased, but only significantly with undiluted odor. Using time-integrated Euclidean distance measures, we determined that added spatiotemporal information was present at the discrimination but not detection threshold. This added information was evidenced by an increase in integrated distance between the sub-detection and discrimination threshold concentrations (of the same odor) that was not present in comparison of the sub-detection and detection threshold. After consideration of delays for information to reach the AL we find that it takes ~120-140 ms for the AL to output identity information. Overall, these results demonstrate that as odor concentration increases, added information about odor identity is embedded in the spatiotemporal representation at the discrimination threshold. |
| first_indexed | 2024-12-13T15:31:54Z |
| format | Article |
| id | doaj.art-8f517ad5b2c24c57a8bda1a572755ce6 |
| institution | Directory Open Access Journal |
| issn | 1662-5102 |
| language | English |
| last_indexed | 2024-12-13T15:31:54Z |
| publishDate | 2016-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Cellular Neuroscience |
| spelling | doaj.art-8f517ad5b2c24c57a8bda1a572755ce62022-12-21T23:40:08ZengFrontiers Media S.A.Frontiers in Cellular Neuroscience1662-51022016-01-01910.3389/fncel.2015.00515164136Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds.Kevin C Daly0Samual P Bradley1Philip D Chapman2Erich M Staudacher3Regina eTiede4Regina eTiede5Joachim eSchachtner6West Virginia UniversityWest Virginia UniversityWest Virginia UniversityWest Virginia UniversityPhilipps-UniversitätUniversity of GöttingenPhilipps-UniversitätAs odor concentration increases, primary olfactory network representations expand in spatial distribution, temporal complexity and duration. However, the direct relationship between concentration dependent odor representations and the psychophysical thresholds of detection and discrimination is poorly understood. This relationship is absolutely critical as thresholds signify transition points whereby representations become meaningful to the organism. Here, we matched stimulus protocols for psychophysical assays and intracellular recordings of antennal lobe projection neurons in the moth Manduca sexta to directly compare psychophysical thresholds and the output representations they elicit. We first behaviorally identified odor detection and discrimination thresholds across an odor dilution series for a panel of structurally similar odors. We then characterized spatiotemporal spiking patterns across a population of individually filled and identified antennal lobe projection neurons in response to those odors at concentrations below, at, and above identified thresholds. Using spatial and spatiotemporal based analyses we observed that each stimulus produced unique representations, even at sub-threshold concentrations. Mean response latency did not decrease and the percent glomerular activation did not increase with concentration until undiluted odor. Furthermore, correlations between spatial patterns for odor decreased, but only significantly with undiluted odor. Using time-integrated Euclidean distance measures, we determined that added spatiotemporal information was present at the discrimination but not detection threshold. This added information was evidenced by an increase in integrated distance between the sub-detection and discrimination threshold concentrations (of the same odor) that was not present in comparison of the sub-detection and detection threshold. After consideration of delays for information to reach the AL we find that it takes ~120-140 ms for the AL to output identity information. Overall, these results demonstrate that as odor concentration increases, added information about odor identity is embedded in the spatiotemporal representation at the discrimination threshold.http://journal.frontiersin.org/Journal/10.3389/fncel.2015.00515/fullPsychophysicsOlfactionodor processingtemporal codespatiotemporal codeSpatial code |
| spellingShingle | Kevin C Daly Samual P Bradley Philip D Chapman Erich M Staudacher Regina eTiede Regina eTiede Joachim eSchachtner Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds. Frontiers in Cellular Neuroscience Psychophysics Olfaction odor processing temporal code spatiotemporal code Spatial code |
| title | Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds. |
| title_full | Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds. |
| title_fullStr | Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds. |
| title_full_unstemmed | Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds. |
| title_short | Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds. |
| title_sort | space takes time concentration dependent output codes from primary olfactory networks rapidly provide additional information at defined discrimination thresholds |
| topic | Psychophysics Olfaction odor processing temporal code spatiotemporal code Spatial code |
| url | http://journal.frontiersin.org/Journal/10.3389/fncel.2015.00515/full |
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