Chapter 15
Odor Sensing
The only defect of our senses is, that they give us disproportion’d
images of things.
(Hume, 1739).
15.1 Basic Model of Odor Sensing
In this chapter we develop a model of a “nose” with three receptors. Each of the
three receptors is tuned to a particular type of odor, either 1, 2 or 3. The goal of the
“nose” is for the dominant receptor to suppress the other two odors in order to send
a clear signal to the brain regarding the type of odor being sensed. The odor changes
over time according to the following rule
ODOR ¼ IF TIME 15 THEN NORMAL 1; :4
ð
Þ ELSE NORMAL 3; :4
ð
Þ ð15:1Þ
Our “nose” can select the mean value out of a normally distributed odor. The
mean value of the odor is thought to be an integer and it is assumed that integers
above 3 would merely require additional receptors. In order for our nose to work,
each receptor has to have a way of forgetting its present signal, should that signal
decrease. We assume that the receptor is constantly forgetting or “zeroing out” the
effect of the signal. Thus, when the strength of a signal to a particular receptor
declines, the strength of the signal transmitted by that receptor declines. The three
receptors are set up accordingly as
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_15,
© Springer International Publishing Switzerland 2014
133
Odor Sensing
The only defect of our senses is, that they give us disproportion’d
images of things.
(Hume, 1739).
15.1 Basic Model of Odor Sensing
In this chapter we develop a model of a “nose” with three receptors. Each of the
three receptors is tuned to a particular type of odor, either 1, 2 or 3. The goal of the
“nose” is for the dominant receptor to suppress the other two odors in order to send
a clear signal to the brain regarding the type of odor being sensed. The odor changes
over time according to the following rule
ODOR ¼ IF TIME 15 THEN NORMAL 1; :4
ð
Þ ELSE NORMAL 3; :4
ð
Þ ð15:1Þ
Our “nose” can select the mean value out of a normally distributed odor. The
mean value of the odor is thought to be an integer and it is assumed that integers
above 3 would merely require additional receptors. In order for our nose to work,
each receptor has to have a way of forgetting its present signal, should that signal
decrease. We assume that the receptor is constantly forgetting or “zeroing out” the
effect of the signal. Thus, when the strength of a signal to a particular receptor
declines, the strength of the signal transmitted by that receptor declines. The three
receptors are set up accordingly as
A save-disabled version of STELLA and the computer models of this book are available at
www.iseesystems.com/modelingdynamicbiologicalsystems.
B. Hannon and M. Ruth, Modeling Dynamic Biological Systems,
Modeling Dynamic Systems, DOI 10.1007/978-3-319-05615-9_15,
© Springer International Publishing Switzerland 2014
133