Olfactory stimulus

Abstract: The orbitofrontal cortex contains the secondary taste cortex, in which the reward value of taste is represented. It also contains the secondary and tertiary olfactory cortical areas, in which information about the identity and also about the reward value of odours is represented. The orbitofrontal cortex also receives information about the sight of objects from the temporal lobe cortical visual areas, and is involved in learning and in reversing stimulus-reinforcement associations. The stimulus might be a visual or olfactory stimulus, and the primary (unlearned) reinforcer a taste or touch. Damage to the orbitofrontal cortex impairs the learning and reversal of stimulus-reinforcement associations, and thus the correction of behavioural responses when these are no longer appropriate because previous reinforcement contingencies change. The information which reaches the orbitofrontal cortex for these functions includes information about faces, and damage to the orbitofrontal cortex can impair face expression identification. This evidence thus shows that the orbitofrontal cortex is involved in decoding some primary reinforcers such as taste; in learning and reversing associations of visual and other stimuli to these primary reinforcers; and plays an executive function in controlling and correcting reward-related and punishment-related behaviour, and thus in emotion.

Abstract: V G Dethier: Chemoreception and behaviour from an evolutionary and comparative perspective BEHAVIOURAL MECHANISMS: J S Kennedy: Some current issues in orientation to odour sources J Murlis: The structure of odour plumes T C Baker: Pheromone-modulated movements of flying moths C T David: Mechanisms of directional flight in wind E Kramer: Turbulent diffusion and pheromone-triggered anemotaxis R Preiss & E Kramer: Pheromone-induced anemotaxis in simulated free flight R J Prokopy: Visual and olfactory stimulus interaction in resource finding by insects J N Perry & C Wall: The effect of habitat on the flight of moths orienting to pheromone sources J H Borden, D W A Hunt, D R Miller, & K N Slessor: Orientation in forest Coleoptera: an uncertain outcome of responses by individual beetles to variable stimuli T L Payne: Olfaction and vision in host finding by a bark beetle C J Sanders: The role of pheromone concentration on male moth flight behaviour J L fqvist: Species specificity in response to pheromone substances in diprionid sawflies J M Pasteels, J L Deneubourg, J-C Verhaeghe, J L Boev 'e, & U Quinet: Orientation along terrestrial trails by ants W J Bell: Responses of arthropods to temporal chemical stimulus changes: simulation of a humidity differential and a pheromone plume R L Jones: Orientation by insect parasitoids P E Howse, J C Lisk, & J W S Bradshaw: The role of pheromones in the control of behavioural sequences in insects J R McLaughlin: Manipulation of orientation to pheromones R J Bartell & E R Rumbo: Correlations between electrophysiological and behavioural responses elicited by pheromone R T Card 'e: Epilogue: behavioural mechanisms PHYSIOLOGICAL MECHANISMS: D Schneider: Physiology of insect olfaction - reflections on the last 30 years K E Kaissling: Temporal characteristics of pheromone receptor cell responses in relation to orientation behaviour of moths R G Vogt & L M Riddiford: Pheromone reception: a kinetic equilibrium C E Linn & W L Roelofs: Neuropharmacological effects on olfactory perception R J O'Connell: Electrophysiological responses to pheromone blends in single olfactory receptor neurones E Priesner: Correlating sensory and behavioural responses in multi-chemical pheromone systems of Lepidoptera J N C Van Der Pers & C L "ofstedt: Signal-response relationship in sex pheromone communication E E Davis: Peripheral chemoreceptors and regulation of insect behaviour J C Dickens: Specificity in perception of pheromones and host odours in Coleoptera H Mustaparta: Allelochemical effects of pheromones: receptor responses F E Hanson, S Kogge, & C Cearley: Computer analysis of chemosensory signals J G Hildebrand & R A Montague: Functional organization of olfactory pathways in the central nervous system of Manduca sexta D M Light: Central integration of sensory signals: an exploration of processing of pheromonal and mult

Abstract: Mammalian urine releases complex mixtures of volatile compounds that are used in reproduction, territoriality and conspecific recognition. To understand how such complex mixtures are represented in the main olfactory bulb, we analysed the electrophysiological responses of individual mitral cells to volatile compounds in mouse urine. In both males and females, urine volatile compounds evoke robust responses in a small subset of mitral cells. Fractionation of the volatile compounds using gas chromatography showed that out of the hundreds of compounds present, mitral cells are activated by single compounds. One cohort of mitral cells responded exclusively to male urine; these neurons were activated by (methylthio)methanethiol, a potent, previously unknown semiochemical present only in male urine. When added to urine, synthetic (methylthio)methanethiol significantly enhances urine attractiveness to female mice. We conclude that mitral cells represent natural odorant stimuli by acting as selective feature detectors, and that their activation is largely independent of the presence of other components in the olfactory stimulus.