Olfactory responses to single odors have been well characterized but in reality we are continually presented with complex mixtures of odors. We performed high-throughput analysis of single-cell responses to odor blends using Swept Confocally Aligned Planar Excitation (SCAPE) microscopy of intact mouse olfactory epithelium, imaging ~10,000 olfactory sensory neurons in parallel. In large numbers of responding cells, mixtures of odors did not elicit a simple sum of the responses to individual components of the blend. Instead, many neurons exhibited either antagonism or enhancement of their response in the presence of another odor. All eight odors tested acted as both agonists and antagonists at different receptors. We propose that this peripheral modulation of responses increases the capacity of the olfactory system to distinguish complex odor mixtures.

Associating an odorant's chemical structure with its percept is a long-standing challenge. One hindrance may come from the adoption of the organic chemistry scheme of molecular description and classification. Chemists classify molecules according to characteristics that are useful in synthesis or isolation, but which may be of little importance to a biological sensory system. Accordingly, we look to medicinal chemistry, which emphasizes biological function over chemical form, in an attempt to discern which among the many molecular features are most important for odour discrimination. Here we use medicinal chemistry concepts to assemble a panel of molecules to test how heteroaromatic ring substitution of the benzene ring will change the odour percept of acetophenone. This work allows us to describe an extensive rule in odorant detection by mammalian olfactory receptors. Whereas organic chemistry would have predicted the ring size and composition to be key features, our work reveals that the topological polar surface area is the key feature for the discrimination of these odorants.

Mechanistic approaches provide alternative solutions to in silico analyses of odorant molecules’ odor-structure relationships.

The piriform cortex (PCX) is the largest component of the olfactory cortex and is hypothesized to be the locus of odor object formation. The distributed odorant representation found in PCX contrasts sharply with the topographical representation seen in other primary sensory cortices, making it difficult to test this view. Recent work in PCX has focused on functional characteristics of these distributed afferent and association fiber systems. However, information regarding the efferent projections of PCX and how those may be involved in odor representation and object recognition has been largely ignored. To investigate this aspect of PCX, we have used the efferent pathway from mouse PCX to the orbitofrontal cortex (OFC). Using double fluorescent retrograde tracing, we identified the output neurons (OPNs) of the PCX that project to two subdivisions of the OFC, the agranular insula and the lateral orbitofrontal cortex (AI-OPNs and LO-OPNs, respectively). We found that both AI-OPNs and LO-OPNs showed a distinct spatial topography within the PCX and fewer than 10% projected to both the AI and the LO as judged by double-labeling. These data revealed that the efferent component of the PCX may be topographically organized. Further, these data suggest a model for functional organization of the PCX in which the OPNs are grouped into parallel output circuits that provide olfactory information to different higher centers. The distributed afferent input from the olfactory bulb and the local PCX association circuits would then ensure a complete olfactory representation, pattern recognition capability, and neuroplasticity in each efferent circuit.olfaction | piriform cortex | olfactory perception T he olfactory system creates perceptual odor objects from often complex mixtures of diverse airborne chemicals (1, 2). This formidable job is mainly accomplished by a surprisingly "shallow" three-level pathway, comprising the olfactory epithelium, olfactory bulb, and olfactory cortex (3). The olfactory epithelium accommodates millions of olfactory sensory neurons (OSNs), each of which can be defined by the particular receptor protein selected for expression from the ∼1,000 odor receptor genes in the typical mammalian genome (4, 5). Axons from all OSNs expressing the same odor receptor coalesce into a few glomeruli on the surface of the olfactory bulb (6-8). Each glomerulus is therefore dedicated to a particular receptor. The position of each glomerulus appears to vary only slightly from animal to animal, giving rise to speculation that the glomeruli form a spatial map of odor sensitivities.Within the glomeruli, the incoming OSN axons form synapses with the apical dendrites of second-order neurons and the mitral and tufted cells, providing what would seem to be an anatomical basis for topographical odorant representation (9-11). Each of about a dozen mitral or tufted cells innervating only a single glomerulus send their axons to targets in a number of ventral forebrain areas, collectively termed the olfactory cortex (12).However, this...

While accent effects have been studied in Western advertising contexts, there are contradictory findings on accent effects, and the moderating role of country‐of‐origin (COO), in other contexts. Few studies extended such accent effects to non‐English‐speaking cultural settings, particularly in emerging countries. This article fills this knowledge gap by examining accent and language effects on consumers’ perceived effectiveness of a spokesperson in Chinese advertising contexts. We explore how Chinese consumers evaluate spokespersons with standard and non‐standard accents, whether these accents are associated with belongingness, sophistication, and modernity, and whether COO moderates such accent and language effects on the perceived effectiveness of spokespersons. Across three studies, the findings demonstrate that compared with a spokesperson with a non‐standard accent (i.e., English‐accented Mandarin), spokespersons with standard accents (i.e., standard Mandarin and standard English) are perceived to be more effective. Furthermore, Chinese consumers associate standard Mandarin with belongingness, and standard English with sophistication and modernity, whereas English‐accented Mandarin has the lowest degree of these associations among the three accents. Although the moderating effect of COO is observed in Study 3, standard English is preferred for both advertised domestic and foreign products.