Olfactory image

These systems are formed by a number of cooperating individual non-selective sensors, whose outputs are processed to form chemical images or, in the presence of odors, olfactory images. 

I. Lundstrom, R. Erlandsson, U. Frykman, E. Hedborg, A. Spetz, H. Sundgren, S. Welin and F. Winquist, Artificial olfactory images from a chemical sensor using a light-pulse technique, Nature, 352(6330) (1991) 47-50. 

I. Lundstrom, C. Svensson, A. Spetz, H. Sundgren and F. Winquist, From hydrogen sensors to olfactory images—twenty years with catalytic field-effect devices, Sens. Actuators B Chem., 13(1-3) (1993) 16-23. 

So far we have considered memory from the point of view of recognition and identification. There is yet another side to memory that is concerned with recall and mental imagery. Here the perfumer is at a natural disadvantage when compared to the artist or musician. Most of us have more or less well developed senses of visual and auditory recall. The ability to see familiar objects in our mind s eye is one that we put to constant use, and the trained artist can reproduce on paper realistic images from memory. Similarly a musician can be trained to know precisely the sound that will be produced from the notes of a musical score, as might be heard in an actual performance. However, the ability to recall smell is usually much less developed. Can we really recall the smell of a rose in the same way that we can recall a color or a melody We may be able to describe the smell and recapture all the associations that go with it, but can we experience a concrete olfactory image of it in our minds ... 

Figure 10. Odour chromatogram, Virtual sensor array, and olfactory image for Primacord. 

An example of such an olfactory image is shown in Fig. 4. This response map was obtained from a sensing surface with in principle two active catalytic metal bands, thin Pd and Pt, and a temperature of 100-110°C at the cool end and 170-180°C at the warm end. 

I Lundstrom, C Svensson, A Spetz, H Sundgren and F Wmquist, From hydrogen sensors to olfactory images - twenty years with catalytic field effect devices. Sensors and Actuators B, 13-14 (1993)16-23... 

Figure 1 Drawings simplifying the structure of the olfactory process by using a motion picture analogy. A) Raw olfactory image created by the translation of information from odorant receptors to the brain. B) Synthesis of perceptions from mixed stimuli. Q Time-dependent processing of multiple precepts creates a movie scene, processed by other brain functions. D) The movie is edited by the brain functions to produce the final dnematographic experience flavor.

FROM STIMULANT MOLECULE TO MOLECULAR IMAGES IN THE OLFACTORY SYSTEM... 

Different odor substances stimulate different patterns of ORCs in the olfactory epithelium, owing to the different sensitivity spectra of the ORCs (28). The pattern of activity in the epithelium evoked by a particular odor substance constitutes the first molecular image of that stimulus, which represents the determinants of the stimulating molecules (13). Thus, although olfaction is not a spatial sensory modality, in contrast, for example, to vision and somatosensation, the initial representation of an odor stimulus in the olfactory pathway does have spatial structure. 

An important insight from many studies (28) is that the response patterns—the molecular images—at various levels in the central olfactory pathway are set up by the differential responses of the ORCs in the peripheral receptor epithelium. These studies also suggest that functional modules, which may correspond to recognizable structural units such as individual glomeruli with their associated cells, in the olfactory bulb or lobe participate in the analysis of olfactory information conveyed to them... 

The electronic nose and electronic tongue will be described as systems able to give olfactory and chemical images, respectively, in a variety of applications fields, including medicine, environment, food and agriculture. 

Since the early 90s, noninvasive functional brain imaging of humans using NIR methods have been slowly gaining momentum despite existence of more established imaging modailties, such as PET, fMRI, and EEG. Part of the reason as stated previously, is because of its relatively high temporal resolution and its ability to monitor multiple tissue chromophores. The technique has been applied to adult as well as infant studies. NIR method is particularly suited for infant studies as the equipment, at least the CW kind, are minimally restraining, relatively safe, and portable [67]. Most neonatal studies focus on sensory stimulation such as visual, auditory and olfactory stimulations [69] [101] [89] [115] [6] [5], and cerebral disfunction [70, 71]. Our review will focus primarily on adult studies with some emphasis on defense and security applications. 

Olfactory research was done by IMAG (Harreveld (2)). The result of such research is the... 

Atema, J., Holland, K., and Ikehara, W. (1980). Olfactory responses of yellow fln tuna [Thunnus albacares) to prey odors chemical search image. Journal of Chemical Ecology 6, 457-465. 

Rubin, B. D. and Katz, L. C. (1999). Optical imaging of odorant representation in the mammalian olfactory bulb. Neuron 23,499-511. 

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