Understanding smell—The olfactory stimulus problem

Abstract

Please cite this article as: Auffarth, B., Understanding smell -the olfactory stimulus problem, Neuroscience and Biobehavioral Reviews (2013), http://dx.doi.org/10.1016/j.neubiorev.2013.06.009. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Page 1 of 27 A c c e p t e d M a n u s c r i p t -For the olfactory system, a topographic organization is disputed. -However, work on different species suggests a topography in olfaction.-We compare other modalities such as taste and color vision.-We discuss the utility of a categorization of smell perception. *Highlights (for review)Page 2 of 27 A c c e p t e d M a n u s c r i p t 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Neuroscience and Biobehavioral Reviews The main problem with sensory processing is the difficulty in relating sensory input to physiological responses and perception. This is especially problematic at higher levels of processing, where complex cues elicit highly specific responses. In olfaction, this relationship is particularly obfuscated by the difficulty of characterizing stimulus statistics and perception. The core questions in olfaction are hence the so-called stimulus problem, which refers to the understanding of the stimulus, and the structure-activity and structure-odor relationships, which refer to the molecular basis of smell. It is widely accepted that the recognition of odorants by receptors is governed by the detection of physico-chemical properties and that the physical space is highly complex. Not surprisingly, ideas differ about how odor stimuli should be classified and about the very nature of information that the brain extracts from odors. Even though there are many measures for smell, there is none that accurately describes all aspects of it. Here, we summarize recent developments in the understanding of olfaction. We argue that an approach to olfactory function where information processing is emphasized could contribute to a high degree to our understanding of smell as a perceptual phenomenon emerging from neural computations. Further, we argue that combined analysis of the stimulus, biology, physiology, and behavior and perception can provide new insights into olfactory function. We hope that the reader can use this review as a competent guide and overview of research activities in olfactory physiology, psychophysics, computation, and psychology. We propose avenues for research, particularly in the systematic characteriza...

An ambusher's arsenal: chemical crypsis in the puff adder (Bitis arietans)

“…The bias for vision comes primarily from the fact that this modality is the predominant human sense [53]. Because olfaction is often a largely unconscious process in humans [54], perceptual dimensions of odours are not well understood and olfaction lacks an intrinsic spatial topology in comparison to other modalities [55]. This has resulted in the importance of olfaction being ignored in many systems.…”

On the Colours of Odours

“…Although humans have an outstanding sense of smell (Sela and Sobel 2010), we often find it difficult to understand and investigate olfaction due to the difficulties in communicating about our olfactory experiences by means of language (Auffarth 2013;Kaeppler and Mueller 2013; though see Koulakov et al 2011;Majid and Burenhult 2014). In fact, it has been suggested that olfactory experience (odour identification, discrimination or even just the perception of an odour's intensity and pleasantness) may benefit substantially from the availability of visual cues, specifically colour cues, thus suggesting the importance of the crossmodal effects that may take place between these two sensory modalities (see Spence 2011; Zellner 2013 for reviews).…”

The Smell Network

“…These matrices here will be represented as perceptual matrix (P), where rows represent molecules (m) and columns percepts (p). Further, in the databases were combined into a common representation of matrix of 3001 molecules and 520 perceptual descriptors.. Olfaction has been a very subjective and contentious of our senses owing to large variations in its reporting which is partly due to the fact that people experience it very differently [9,10,11]. The only non-invasive method of its reporting in humans is via language.…”

“…Olfaction has been a very subjective and contentious of our senses owing to large variations in its reporting which is partly due to the fact that people experience it very differently [9,10,11]. The only non-invasive method of its reporting in humans is via language.…”