Neural Networks B, SS06
UA Dr. Robert Legenstein, WiMAus Prashant Joshi, M.S.
Institute for Theoretical Computer Science
Technische Universität Graz
A-8010 Graz, Austria
NOTE: You can download this exercise in pdf or postscript(ps) format here.
This exercise is based on the neuron tutorial availaible here2. This exercise uses
part A and B of the tutorial only.
- First follow the instructions of part A. At the end you must be able to
get a plot of the membrane potential of the soma. Submit this plot. If it
is not clear as to how to print your plots, then please read the section
``The Print and File Window Manager'' from tutorial part B.
- Now please read pages 9-14 of ``NEURON: a Tool for Neuroscientists'' which can be found
here3 (section ``Choosing the spatial grid''). As you
can see choosing the correct spatial resolution (i.e. the no. of compartments)
is very important for accuracy of simulations.
Now go ahead to section ``Cables'' in Part B of the tutorial. Compute the values
for dendrite, dendrite and the soma.
- In part B, section ``Making the neurons subthalamic'' check that your code is running
correctly. At the end of this section it says ``This is a good time to run the model and
explore ...''. Now try moving the current injection to and down the length
of dendrites4. Plot the voltage at the center of soma, and at these 4
injection locations on a single plot(so you will have 4 plots with 5 traces on each plot). Set
the stimulus as (
). Write a small note about
- Now experiment with different fractions of
for compartment lengths. Write your
script such that nsegs is set automatically to make compartment lengths a fraction of
You can start with , but make this a sensibly named variable. located somewhere on the top
of your script file.
- (For 5 BONUS points!) Rerun the simulation making the segments
For each fraction of
run the simulation with different input currents, e.g.
and . You may need to make the duration for current injection longer to make it fire
for small current amplitudes. Also try it with the current injection in the soma, and and
of the way down the longer dendrite. Submit a few of these plots which illustrate the difference that you see
Write a small paragraph discussing your observations.
- Different fractions of
for compartment lengths.
- Different levels of current injections.
- Different locations of current injections.
- Submit a printout of the script that you used for your simulations.
Neural Networks B, SS06
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- ... SS061
- Class Website: http://www.igi.tugraz.at/lehre/NNB/SS06/
- ... here2
- ... here3
- ... dendrites4
- i.e. 4 different IClamp locations, dendrite(0.3), dendrite(0.7),
dendrite(0.3) and dendrite(0.7)