In July 1989 a symposium was held at the Physiology Department of the Georg August University, G6ttingen, on the physiological, biophysical, biochemical, and technical principles of the coding of chemical substances both in nervous systems and artificial devices. This book is the collection of the papers presented at that meeting. Biological and artificial systems for odor coding both have in common that the stimulus selectivity of the receptor cells (sensors) is usually very poor, and the mechanisms which determine selectivity and sensitivity are largely unknown. However, a poor selectivity allows the coding of an enormous number of stimuli by combinations of receptor activities. In the field of chemosensory information coding there are thus two major problems: the function of the receptors and the network that processes and evaluates the primary information of the sensors. Accordingly, this volume has three parts: sensors, the network following the sensors, and the coding in this network. The expert secretarial assistance of M. Holtmann in preparing the camera-ready manuscript is gratefully acknowledged. D. Schild G6ttingen, August 1989 CONTENTS l. Response of olfactory receptor cells, isolated and in situ, to low concentrations of odorants 1 Stephan Frings, Bernd Lindemann 2. Excitation and adaptation of frog olfactory receptor neurones upon stimulation with second messengers and natural odorants 9 D. Schild, J. A. DeSimone, S. Hellwig 3. Receptor selectivity and dimensionality of odours at the stage of the olfactory receptor cells 21 GiJJes Sicard 4.

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1. Response of olfactory receptor cells, isolated and in situ, to low concentrations of odorants.- 2. Excitation and adaptation of frog olfactory receptor neurones upon stimulation with second messengers and natural odorants.- 3. Receptor selectivity and dimensionality of odours at the stage of the olfactory receptor cells.- 4. The biochemistry of odorant reception and transduction.- 5. Molecular elements of olfactory signal transduction in insect antennae.- 6. The Xenopus oocyte as an in vitro translation and expression system for chemosensory - specific gene products.- 7. Stimulus properties and binding to receptors.- 8. Principles and properties of some solid state chemical sensors.- 9. Purification of an odorant binding protein from human nasal mucosa.- 10. The design of an artificial olfactory system.- 11. Morphological basis of information processing in the olfactory bulb.- 12. Olfactory bulb plasticity.- 13. Olfactory bulb and antennal lobe.- 14. Processing of pheromone information from receptor cells to antennal lobe neurons in heliothis moths.- 15. Single cell activities and the olfactory code.- 16. Is the olfactory bulb functionally organized in parallel columns ?.- 17. Perceptual performance in peripherally reduced olfactory systems.- 18. Scent trailing by tracking dogs. What is the physiological basis for concentration coding ?.- 19. Extracting information from spike trains of olfactory bulb neurons.- 20. Optical recording of neuronal activity: parallel versus serial methods.- 21. Temporal patterns of membrane potential in the olfactory bulb observed with intracellular recording and voltage-sensitive dye imaging: early hyperpolarization..- 22. Optical mapping of the olfactory system activity using voltage-sensitive dyes.- 23. Animated pseudocolor activity maps (PAM's): scientific visualization of brain electrical activity.- 24. Chemosensors with pattern recognition.- 25. Monte Carlo generation of chemosensory maps in the olfactory bulb: glomerular activity patterns.- 26. Olfactory EEG changes under serial discrimination of odorants by rabbits.