Function and Morphology of the Antennal Lobe: New Developments

The antennal lobe of insects has emerged as an excellent model for olfactory processing in the CNS. In the present review we compile data from areas where substantial progress has been made during recent years: structure-function relationships within the glomerular array, integration and blend specificity, time coding and the effects of neuroactive substances and hormones on antennal lobe processing

Olfactory signal coding in an odor background

AbstractInsects communicating with pheromones are confronted with an olfactory environment featuring a diversity of volatile organic compounds from plant origin. These volatiles constitute a rich and fluctuant background from which the information carried by the pheromone signal must be extracted. Thus, the pheromone receptor neurons must encode into spike trains the quality, intensity and temporal characteristics of the signal that are determinant to the recognition and localization of a conspecific female. We recorded and analyzed the responses of the pheromone olfactory receptor neurons of male moths to sex pheromone in different odor background conditions. We show that in spite of the narrow chemical tuning of the pheromone receptor neurons, the sensory input can be altered by odorant background

Pest Insect Olfaction in an Insecticide-Contaminated Environment: Info-Disruption or Hormesis Effect

Most animals, including pest insects, live in an “odor world” and depend strongly on chemical stimuli to get information on their biotic and abiotic environment. Although integrated pest management strategies including the use of insect growth regulators (IGRs) are increasingly developed, most insect pest treatments rely on neurotoxic chemicals. These molecules are known to disrupt synaptic transmission, affecting therefore sensory systems. The wide-spread use of neurotoxic insecticides and the growing use of IGRs result in residual accumulation of low concentrations in the environment. These insecticide residues could act as an “info-disruptor” by modifying the chemical communication system, and therefore decrease chances of reproduction in target insects. However, residues can also induce a non-expected hormesis effect by enhancing reproduction abilities. Low insecticide doses might thus induce adaptive processes in the olfactory pathway of target insects, favoring the development of resistance. The effect of sublethal doses of insecticides has mainly been studied in beneficial insects such as honeybees. We review here what is known on the effects of sublethal doses of insecticides on the olfactory system of insect pests

Mating-induced transient inhibition of responses to sex pheromone in a male moth is not mediated by octopamine or serotonin

In the male moth, Agrotis ipsilon, mating induces a transient inhibition of behavioural and central nervous responses to sex pheromone. Newly mated males are not attracted to sex pheromone, and the sensitivity of their antennal lobe (AL) neurons is lower than in virgin males. This rapid transient olfactory inhibition prevents them from re-mating unsuccessfully until they have refilled their sex glands. We hypothesized that this olfactory ‘switch off’ might be controlled by neuromodulators such as biogenic amines. To test our hypothesis, we studied the effects of octopamine (OA) and serotonin (5-hydroxytryptamine, 5-HT) on the coding properties of pheromone-sensitive AL neurons in virgin and newly mated males. We show that AL neuron sensitivity increased in newly mated males after injection of OA or 5-HT, but only OA treatment affected certain response characteristics of AL neurons in virgin males. Whereas all measured AL neuron response characteristics were different between virgin and newly mated males, amine treatment in newly mated males restored only the latency and spike frequency, but not the duration of excitatory and inhibitory phases, which were initially found in virgin males. Additionally, we investigated the behavioural effects of OA and 5-HT treatments in virgin and mated males. Although OA and 5-HT enhanced the general flight activity of newly mated males, amine treatments did not restore the behavioural pheromone response of mated moths. Altogether, these results show that, although biogenic amines modulate the olfactory system in moths, OA and 5-HT are probably not involved in the post-mating inhibition of responses to sex pheromone in A. ipsilon males.Fil: Barrozo, Romina. Institut National de la Recherche Agronomique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jarriault, David. Institut National de la Recherche Agronomique; FranciaFil: Simeone, Xenia. Institut National de la Recherche Agronomique; FranciaFil: Gaertner, Cyril. Institut National de la Recherche Agronomique; FranciaFil: Gadenne, Christophe. Institut National de la Recherche Agronomique; FranciaFil: Anton, Sylvia. Institut National de la Recherche Agronomique; Franci

Editorial: Coding Properties in Invertebrate Sensory Systems.

Editorial: Coding properties in invertebrate sensory system

A Novel Gene Family Controls Species-Specific Morphological Traits in Hydra

Understanding the molecular events that underlie the evolution of morphological diversity is a major challenge in biology. Here, to identify genes whose expression correlates with species-specific morphologies, we compared transcriptomes of two closely related Hydra species. We find that species-specific differences in tentacle formation correlate with expression of a taxonomically restricted gene encoding a small secreted protein. We show that gain of function induces changes in morphology that mirror the phenotypic differences observed between species. These results suggest that “novel” genes may be involved in the generation of species-specific morphological traits

A Case Study of Organizational and Curricular Attributes for Interprofessional Education: A Model for Sustainable Curriculum Delivery

Background: In health and social care (HASC) professional education, interprofessional competencies are optimally developed by engaging in interprofessional education (IPE) activities that are delivered sustainably along a continuum. Ultimately, active engagement in IPE is meant to prepare future practitioners for interprofessional collaborative practice (IPCP), which leads to improved patient/client and community-oriented outcomes. Methods and Findings: This qualitative case study explores how four Canadian post-secondary institutions deliver IPE within their HASC professional education programmatic structures. Data were collected from institutional websites, publicly available IPE relevant records and documents, and interviews with coordinators and faculty/facilitators of IPE curriculum. Data were inductively analyzed to generate relevant themes, followed by a deductive analysis guided by the five accreditation standards domains identified in the Accreditation of Interprofessional Health Education (AIPHE) projects. Analyses of the data resulted in five attributes: 1) central administrative unit, 2) longitudinal and integrative program, 3) theoretically informed curriculum design, 4) student-centred pedagogy, and 5) patient/client-oriented approach. Conclusions: Using these attributes and guided by AIPHE’s accreditation standards domains, an organizational-curricular model for sustainable IPE is proposed, through which we assert that IPE reinforced through these organizational and curricular supports reflects successful programming, leading to patient/client-oriented outcomes

Machine learning for automatic prediction of the quality of electrophysiological recordings

The quality of electrophysiological recordings varies a lot due to technical and biological variability and neuroscientists inevitably have to select “good” recordings for further analyses. This procedure is time-consuming and prone to selection biases. Here, we investigate replacing human decisions by a machine learning approach. We define 16 features, such as spike height and width, select the most informative ones using a wrapper method and train a classifier to reproduce the judgement of one of our expert electrophysiologists. Generalisation performance is then assessed on unseen data, classified by the same or by another expert. We observe that the learning machine can be equally, if not more, consistent in its judgements as individual experts amongst each other. Best performance is achieved for a limited number of informative features; the optimal feature set being different from one data set to another. With 80–90% of correct judgements, the performance of the system is very promising within the data sets of each expert but judgments are less reliable when it is used across sets of recordings from different experts. We conclude that the proposed approach is relevant to the selection of electrophysiological recordings, provided parameters are adjusted to different types of experiments and to individual experimenters