As discussed in Sections 3 and 4, olfactory and gustatory cognitions have close links to emotion and memory, from both the psychological and physiological points of view. The chapters in this section will complement the preceding studies and focus on the neural bases supporting the neural code and chemical-sense cognition, while most often taking into account these emotional and memory dimensions. In Chapter 18, Gilles Sicard reviews recent findings on neuroreceptor identification and the patterns that have emerged in the neural representation of odors at the level of neuroreceptors and the olfactory bulb, emphasizing a potentially important role for neural assemblies in odor detection and recognition.

The chapters in this section deal with phenomena observed over different time scales and under different experimental conditions, varying from one study to the next, and the concepts of neural dynamics are not always easy to follow. Several sets of data presented in the following chapters will illustrate this point. For instance, in Chapter 19, Bettina Pause examines the effects of cognitive dimensions such as attention, habituation, and short-term memory on the characteristics of olfactory-related evoked potentials recorded from the scalp in humans. She reports on pronounced modulations of some evoked-potential components occurring within the first second after stimulus onset. In Chapter 20, Robert Zatorre reviews the findings on the contributions of functional imaging studies to our understanding of the processing of olfactory affective information.