Biology Reference
In-Depth Information
FIGURE 4.6
Basic view of the Agent Based Model. On the left is the initial setup with black and gray
circles representing Netrin and Slit sources and bug-like shapes (
agents
) representing
the four growth cone types a-d, labeled as in Fig.
4.5
and §
4.2.4
. The right hand picture
shows the results of a single run of the code (see text for information).
Exercise 4.26.
Make sure you refer to §
4.2.2
to help answer these questions.
a.
What are the
environmental
features?
b.
Which part of the biology should be identified as the
agent
?
c.
How should the
agent
interact with the
environment
?
These assumptions can now be transferred into an ABM.
4.2.4
Constructing a Model of Axon Development
Figure
4.6
shows output from the model of Worku, taken from her Honors Thesis
“Agent-based Modeling of Commissural Axon Guidance along the Midline" [
31
].
The midline is represented by black and gray circles which indicate where Netrin
and Slit are produced. The four bug shaped
agents
(a-d) represent the four types of
growth cones discussed earlier, see Figure
4.5
. A basic simulation, where a single
axon of each receptor type is modeled, can be seen in Figure
4.6
, and the results can
be summarized as follows:
a
.
growth cones which initially express only DCC receptors are able to cross the
midline, whereupon the Robo 1 receptor is expressed, restricting the growth cone
to the opposite side of the midline and repulsing it away.
b
.
growth cones expressing both UNC5 and Robo 1 receptors are repelled from the
midline and grow away from it.
c
.
growth cones expressing only the UNC 5 receptor move randomly until they are
close to the midline (where the Netrin levels are high) whereupon the guidance
cue gradient repels the growth cone.
Search WWH ::
Custom Search