All mammals have pretty much the same set of 1000 genes

All mammals have pretty much the same set of 1000 genes -...

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o All mammals have pretty much the same set of 1000 genes. However, some genes are non-functional pseudogenes Dogs and mice: about 20% are pseudogenes Humans: between 60-70% are pseudogenes Each person has a different number of pseudogenes resulting in individual differences in sensitivity to smells There may be an evolutionary trade-off between vision and olfaction Theory of odor identification o Specificity coding- perhaps each OSN uniquely responds to a particular odorant molecule BUT…we can recognize about 10,000 different cells, but have only about 1000 different receptor types o Distributed coding – perhaps each odor is represented by a pattern of activity across multiple receptor types A given odorant will excite several receptors A given receptor will respond to several odorants Each mitral cells receives input from only one receptor type o Structurally similar odorants produce activity in nearby regions of olfactory bulb, BUT odors represented in similar location don’t necessarily smell similarly
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Unformatted text preview: Odor detection and recognition o Olfactory detection thresholds and recognition ability depends on several factors, including: Chemical compound Sex Expertise Age o Odor detection Psychophysical methods Staircase method method for determining the concentration of stimulus required for detection at a threshold level o Stimulus is presented in increasing concentration until detection is indicated o Then o Odor discrimination Psychophysical method Triangle test participant is given three odors to smell, two of which are the same and one is different o Participants must identify the odd odor o The order of the three odors is varied and tested several times o Sex differences Females tend to outperform males in test of detection(lower thresholds) and discrimination, particularly if they are ovulating Cain (1982) presented males and females with 80 different common odorants and asked them to identify each one...
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This note was uploaded on 11/27/2011 for the course PSYC 225 taught by Professor Staff during the Fall '10 term at UNC.

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All mammals have pretty much the same set of 1000 genes -...

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