Physiology and Psychophysics in Taste and Smell

The ability to recognize chemical stimuli in the external environment is a feature of living organisms ranging from bacteria to man. It has played a crucial role in the search for food, detection of adverse environments, and sexual behaviour. The transduction process of chemoreception in both lower organisms and higher vertebrates consists of binding of chemical stimuli to a receptor membrane, giving rise to a receptor generator potential. This potential either triggers a chemotactic response in lower organisms or is transmitted in the form of neural impulses to signal processing centres in higher animals. In vertebrates, chemical stimuli in external environments are received at gustatory and olfactory receptor cells. These cells detect chemicals, encode information about the intensity, duration and quality and transmit it to higher processing centres. This chapter discusses some aspects of current research in the physiology and psychophysics of taste and smell in vertebrates.