Precise and Fuzzy Coding by Olfactory Sensory Neurons

Hoare, Derek J.; McCrohan, Catherine R.; Cobb, Matthew

doi:10.1523/jneurosci.1955-08.2008

Cited by 23 publications

(43 citation statements)

References 33 publications

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“…Typical electrophysiological recordings for three OSN classes and four odors are shown in Figure 1A; the traces for each OSN class were from a single larva and also included spontaneous activity in other, non-functional OSNs. There was no evidence that the activity of a responding OSN altered the spontaneous activity of the non-functional Orco −/− OSNs, confirming our previous report [4]. There were no significant correlations between the maximum absolute activity observed for each OSN class during odor stimulation and the maximum level of spontaneous activity ( r 15 = −.052, p = 0.847) (Table 1), between maximum absolute activity during odor stimulation and mean spontaneous activity ( r 15 = 0.024, p = 0.929), or between maximum activity during a response and mean spontaneous activity ( r 15 = 0.006, p = 0.983), indicating that response intensity in a given OSN was independent of its level of spontaneous activity.…”

Section: Resultssupporting

confidence: 90%

“…We extend our previous finding that many odor-OSN combinations yield highly variable responses; based on an objective probabilistic criterion, many ‘responses’ are not statistically different from spontaneous changes in background firing activity in the same neuron [4]. Response uncertainty in the peripheral olfactory system has been reported for other organisms.…”

Section: Discussionsupporting

confidence: 80%

“…OSNs of a given class responded reliably to some odors, but not to others. This variability was consistent for specific odor-OSN pairs and was not dependent on odor type or concentration, stimulus duration, genotype or inter-individual differences [4]. Decisively, in larvae expressing only two functional OSNs, one OSN class showed 100% responses to repeated, identical presentations of a given odor, whilst the other OSN class showed variable (<100%) responses to the same presentations of the same odor [4].…”

Section: Introductionmentioning

confidence: 68%

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Modeling Peripheral Olfactory Coding in Drosophila Larvae

et al. 2011

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The Drosophila larva possesses just 21 unique and identifiable pairs of olfactory sensory neurons (OSNs), enabling investigation of the contribution of individual OSN classes to the peripheral olfactory code. We combined electrophysiological and computational modeling to explore the nature of the peripheral olfactory code in situ. We recorded firing responses of 19/21 OSNs to a panel of 19 odors. This was achieved by creating larvae expressing just one functioning class of odorant receptor, and hence OSN. Odor response profiles of each OSN class were highly specific and unique. However many OSN-odor pairs yielded variable responses, some of which were statistically indistinguishable from background activity. We used these electrophysiological data, incorporating both responses and spontaneous firing activity, to develop a Bayesian decoding model of olfactory processing. The model was able to accurately predict odor identity from raw OSN responses; prediction accuracy ranged from 12%–77% (mean for all odors 45.2%) but was always significantly above chance (5.6%). However, there was no correlation between prediction accuracy for a given odor and the strength of responses of wild-type larvae to the same odor in a behavioral assay. We also used the model to predict the ability of the code to discriminate between pairs of odors. Some of these predictions were supported in a behavioral discrimination (masking) assay but others were not. We conclude that our model of the peripheral code represents basic features of odor detection and discrimination, yielding insights into the information available to higher processing structures in the brain.

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Section: Resultssupporting

confidence: 90%

Section: Discussionsupporting

confidence: 80%

Section: Introductionmentioning

confidence: 68%

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Modeling Peripheral Olfactory Coding in Drosophila Larvae

et al. 2011

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“…In the Orco null background, spontaneous activity of OSNs is drastically reduced but not abolished (Hoare et al, 2008). Furthermore, non-OSNs contribute to the activity monitored from the DO ganglion.…”

Section: Methodsmentioning

confidence: 99%

Dynamical feature extraction at the sensory periphery guides chemotaxis

Schulze

Gomez‐Marin

Rajendran

et al. 2015

eLife

110

187

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Behavioral strategies employed for chemotaxis have been described across phyla, but the sensorimotor basis of this phenomenon has seldom been studied in naturalistic contexts. Here, we examine how signals experienced during free olfactory behaviors are processed by first-order olfactory sensory neurons (OSNs) of the Drosophila larva. We find that OSNs can act as differentiators that transiently normalize stimulus intensity—a property potentially derived from a combination of integral feedback and feed-forward regulation of olfactory transduction. In olfactory virtual reality experiments, we report that high activity levels of the OSN suppress turning, whereas low activity levels facilitate turning. Using a generalized linear model, we explain how peripheral encoding of olfactory stimuli modulates the probability of switching from a run to a turn. Our work clarifies the link between computations carried out at the sensory periphery and action selection underlying navigation in odor gradients.DOI: http://dx.doi.org/10.7554/eLife.06694.001

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“…For this to happen, the olfactory system must be versatile enough to entertain new odor exposures and relate them with past smell experiences. Olfactory receptors may thus be adaptable to new and unpredictable chemical combinations and new odorant molecules perceived as if fuzzy-encoded rather than set in a precise key-and-lock mode (Hoare et al 2008).…”

Section: Biosemiotic Analysismentioning

confidence: 99%

Are Olfactory Receptors Really Olfactive?

2011

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Any living organism interacts with and responds specifically to environmental molecules by expressing specific olfactory receptors. In this paper, this specificity will be first examined in causal terms with particular emphasis on the mechanisms controlling olfactory gene expression, cell-to-cell interactions and odordecoding processes. However, this type of explanation does not entirely justify the role olfactory receptors have played during evolution, since they are also expressed ectopically in different organs and/or tissues. Homologous olfactory genes have in fact been found in such diverse cells and/or organs as spermatozoa, testis and kidney where they are assumed to act as chemotactic sensors or renin modulators. To justify their functional diversity, homologous olfactory receptors are assumed to share the same basic role: that of conferring a self-identity to cells or tissues under varying environmental conditions. By adopting this standpoint, the functional attribution as olfactory or chemotactic sensors to these receptors should not be seen either as a cause conditioning receptor gene expression, or as a final effect resulting from genetically predetermined programs, but as a direct consequence of the environmental conditions olfactory receptor genes have explored during evolution. The association of odorant patterns with specific environmental or contextual situations makes their relationship semiotically triadic, due to the emergence of an interpretant capable of perceiving odorants as meaningful signs out of a noisy background. This perspective highlights the importance of odorant-receptor relationships as respect to the properties of the interacting partners. It is our contention that only when taken together can these different explanatory strategies provide a realistic account of how olfactory receptor genes have been structurally and functionally modified during evolution.

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Precise and Fuzzy Coding by Olfactory Sensory Neurons

Cited by 23 publications

References 33 publications

Modeling Peripheral Olfactory Coding in Drosophila Larvae

Modeling Peripheral Olfactory Coding in Drosophila Larvae

Dynamical feature extraction at the sensory periphery guides chemotaxis

Are Olfactory Receptors Really Olfactive?

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