| 1. |
- Andersson, Linus, 1979-, et al.
(författare)
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Effects of Task Demands on Olfactory, Auditory, and Visual Event-Related Potentials Suggest Similar Top-Down Modulation Across Senses
- 2018
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 43:2, s. 129-134
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Tidskriftsartikel (refereegranskat)abstract
- A widely held view is that top-down modulation of sensory information relies on an amodal control network that acts through the thalamus to regulate incoming signals. Olfaction lacks a direct thalamic projection, which suggests that it may differ from other modalities in this regard. We investigated the late positive complex (LPC) amplitudes of event-related potentials (ERP) from 28 participants, elicited by intensity-matched olfactory, auditory and visual stimuli, during a condition of focused attention, a neutral condition, and a condition in which stimuli were to be actively ignored. Amplitudes were largest during the attend condition, lowest during the ignore condition, with the neutral condition in between. A Bayesian analysis resulted in strong evidence for similar effects of task across sensory modalities. We conclude that olfaction, despite its unique neural projections, does not differ from audition and vision in terms of task-dependent neural modulation of the LPC.
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| 2. |
- Andersson, Linus, 1979-, et al.
(författare)
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Highlighting the large variation in perceived properties of odors over time
- 2017
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Ingår i: Chemical Senses. - 0379-864X .- 1464-3553. ; 42:2, s. E26-
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Tidskriftsartikel (refereegranskat)abstract
- Individuals differ considerably when rating the perceived properties of odors, especially over time. A second glance at previously published data-sets from our laboratory revealed that the same invariant exposure often produced both floor and roof effects. An odor that at the end of the exposure ses-sion was regarded as non-existent by one participant, could border the “absoulte maximum” rating category in another. We provide re-analyses from four exposure studies where we illustrate the perceptual variability over time, and outcomes associated with such ratings. We note that high, compared with low ratings of odor intensity over time is associated with ratings of unpleasantness and symptoms, but also with everyday distress, cognitive performance, autonomous nerv-ous system activity and deviating responses in the so-called pain or saliency matrix of the brain. We bring an open ques-tion to ECRO regarding how this considerable variability should be interpreted, and what the consequenced are for research and for setting exposure limits.
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| 3. |
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| 4. |
- Andersson, Martin N, et al.
(författare)
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What Reaches the Antenna? How to Calibrate Odor Flux and Ligand-Receptor Affinities
- 2012
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 1464-3553 .- 0379-864X. ; 37:5, s. 403-420
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Tidskriftsartikel (refereegranskat)abstract
- Physiological studies on olfaction frequently ignore the airborne quantities of stimuli reaching the sensory organ. We used a gas chromatography-calibrated photoionization detector to estimate quantities released from standard Pasteur pipette stimulus cartridges during repeated puffing of 27 compounds and verified how lack of quantification could obscure olfactory sensory neuron (OSN) affinities. Chemical structure of the stimulus, solvent, dose, storage condition, puff interval, and puff number all influenced airborne quantities. A model including boiling point and lipophilicity, but excluding vapor pressure, predicted airborne quantities from stimuli in paraffin oil on filter paper. We recorded OSN responses of Drosophila melanogaster, Ips typographus, and Culex quinquefasciatus, to known quantities of airborne stimuli. These demonstrate that inferred OSN tuning width, ligand affinity, and classification can be confounded and require stimulus quantification. Additionally, proper dose-response analysis shows that Drosophila AB3A OSNs are not promiscuous, but highly specific for ethyl hexanoate, with other earlier proposed ligands 10- to 10 000-fold less potent. Finally, we reanalyzed published Drosophila OSN data (DoOR) and demonstrate substantial shifts in affinities after compensation for quantity and puff number. We conclude that consistent experimental protocols are necessary for correct OSN classification and present some simple rules that make calibration, even retroactively, readily possible.
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| 5. |
- Baker, Thomas C., et al.
(författare)
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Adaptation of male moth antennal neurons in a pheromone plume is associated with cessation of pheromone-mediated flight
- 1989
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 14:3, s. 439-448
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Tidskriftsartikel (refereegranskat)abstract
- Recordings of the firing rates of single antennal neurons when Agrotis segetum antennac were placed 70 cm downwind of a pheromone source revealed that cells sensitive to the most volatile component adapted rapidly in a plume from a high-concentration source known from previous studies to cause in-flight arrestment of progress towards the source. No adaptation was found in response to lower-concentration plumes known to promote high levels of sustained flight to the source with little premature arrestment. Adaptation was not observed in antennal neurons of a second species, Heliothis virescens, when they were placed in plumes of this species' sex pheromone blend, regardless of the concentration. In flight-tunnel tests these same pheromone sources evoked high levels of source location with little arrestment. These results indicate that adaptation or attenuation of antennal neuronal burst frequencies in response to rapidly arriving pheromone filaments in a plume may be important peripheral determinants of whether or not prolonged upwind flight and successful pheromone source location occurs.
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| 6. |
- Bengtsson, Jonas, et al.
(författare)
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Conserved, Highly Specialized Olfactory Receptor Neurons for Food Compounds in 2 Congeneric Scarab Beetles, Pachnoda interrupta and Pachnoda marginata
- 2011
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 36, s. 499-513
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Tidskriftsartikel (refereegranskat)abstract
- Few studies have systematically addressed evolutionary changes in olfactory neuron assemblies, either by genetic drift or as an adaptation to specific odor environments. We have studied the sense of olfaction in 2 congeneric scarab beetles, Pachnoda interrupta Olivier and Pachnoda marginata Drury (Coleoptera: Scarabaeidae: Cetoniinae), which are both opportunistic polyphages, feeding mainly on fruit and flowers. The 2 species occur in dissimilar habitats: P. interrupta is found in dry savannah, and P. marginata in tropical parts of equatorial Africa. To study how these species may have adapted their sense of olfaction to their odor environments, we utilized single-unit electrophysiology on olfactory sensilla with a wide selection of food-related compounds. Despite the differences in habitat, we found that the species shared most of the physiological types of olfactory receptor neurons (ORNs) encountered, although their proportions frequently varied between the species. The high degree of conservation in olfaction between the species implies that a similar sensory strategy is efficient for food search in both habitats. However, shifts in proportions of receptor neuron classes, and slight shifts in response profiles and/or presence of some ORN classes unique to either species, may reflect adaptation to a different set of hosts.
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| 9. |
- Bichao, H., et al.
(författare)
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Five types of olfactory receptor neurons in the strawberry blossom weevil Anthonomus rubi : Selective responses to inducible host-plant volatiles
- 2005
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 30:2, s. 153-170
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Tidskriftsartikel (refereegranskat)abstract
- Plants release hundreds of volatiles that are important in the interaction with herbivorous animals, but which odorants are detected by which species? In this study, single receptor neurons on the antenna of the oligophagous strawberry blossom weevil Anthonomus rubi were screened for sensitivity to naturally produced plant compounds by the use of gas chromatography linked to electrophysiological recordings from single cells. The narrow tuning of the neurons was demonstrated by responses solely to a few structurally related sesquiterpenes, aromatics or monoterpene hydrocarbons out of hundreds of plant constituents tested. We present five olfactory receptor neuron types, identified according to one primary odorant i.e. the compound to which the neurons are most sensitive. These odorants, (-)-germacrene D, (-)-beta-caryophyllene, methyl salicylate, E-beta-ocimene and (3E)-4,8-dimethyl-1,3,7-nonatriene, present in the intact strawberry plant, are induced in higher amounts by weevil feeding. This suggests that these compounds can provide information about the presence of conspecifics. We used protocols especially designed to allow comparison with previously investigated species. Striking similarities, but also differences, are demonstrated between receptor neuron specificity in the strawberry weevil and moths.
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| 10. |
- Binyameen, Muhammad, et al.
(författare)
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Identification of Plant Semiochemicals and Characterization of New Olfactory Sensory Neuron Types in a Polyphagous Pest Moth, Spodoptera littoralis
- 2014
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 39, s. 719-733
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Tidskriftsartikel (refereegranskat)abstract
- Phytophagous insects use blends of volatiles released from plants to select hosts for feeding and oviposition. To behaviorally analyze complex blends, we need efficient and selective methods for elucidating neuron types, their ligands, and specificity. Gas chromatography-combined single sensillum recordings (GC-SSRs) from antennal olfactory sensilla of female moth, Spodoptera littoralis revealed 38 physiologically active peaks in the headspace volatile blends from both larvae-damaged cotton plants and lilac flowers. Using GC-combined mass spectrometry, 9 new physiologically active compounds were identified from damaged cotton and 11 from lilac compared with earlier electrophysiological studies using antennae of female S. littoralis. We characterized 14 novel classes of olfactory sensory neurons (OSNs). Among these, we found the first 2 ligands for a frequent type of short trichoid sensillum, for which no ligands were identified earlier. By using GC-SSR, a substantial increase in functional classes of OSNs and active compounds, 40% and 34% more, respectively, compared with recent studies using GC-electroantennogram or SSR using single compounds was detected. Compared with the estimated number of corresponding antennal olfactory receptors, the OSN classes now correspond to 83% of a likely maximum. The many specialist OSNs observed may facilitate behavioral confirmation of key plant volatiles in blends.
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