Olfactory System

This book provides a comprehensive summary of the recent advances in the understanding of the mammalian and fish olfactory system, providing an understanding of the basic neurobiological mechanisms involved in the functioning of the associated neuronal circuits. Despite the rapid progress in understanding the olfactory system following the identification of the odorant receptor gene family more than two decades ago, it is still unclear how the odor information is processed at the levels beyond the olfactory bulb that includes olfactory cortex, olfactory tubercle, amygdala, and orbitofrontal cortex. The functional logic that translates odor information into behavioral responses includes not only reflex-like simple neuronal connections between odor signals and behavioral outputs (so called Zombie circuits or lower circuits) but also higher neuronal circuits responsible for the learning and memory of olfactory image of objects , the conscious or non-conscious attention to and valuation of olfactory signals of foods and dangers and the action plan to obtain the rewards and avoid the danger . A unique feature of the olfactory system is that the higher neuronal circuits (e.g., orbitofrontal cortex and olfactory tubercle) are only a few synapses away from olfactory sensory neurons. §Future progress in understanding the functional logic of neuronal circuits in the olfactory system is expected to play a central role in understanding the higher functions of the brain in general. Thus this book will also be valuable to the next-generation scientists who are interested in neuroscience, neurobiology, chemical senses, food and nutrition science, medical sciences and/or behavioral science.