Neural Networks B, SS06 1

UA Dr. Robert Legenstein, WiMAus Prashant Joshi, M.S.

Institute for Theoretical Computer Science
Technische Universität Graz
A-8010 Graz, Austria
{legi, joshi}

NACHNAME Vorname Matrikelnmr Teammitglieder

Synchrony of two I&F Neurons

NOTE: You can download this exercise in pdf or postscript(ps) format here.

The questions 1 to 5 are for 10 points in total. Question 6 is a bonus question for 3 points.

The action potentials of two coupled I&F neurons may synchronize. In this exercise, you will examine the circumstances under which two coupled I&F neurons synchronise.

The Matlab program simulates two I&F neuons which are mutually coupled by two synapses. It plots the temporal evolution of the membrane potential, the spikes and the PSCs. You need to unzip the file into the same directory as sync.m to make sync.m work. (it contains csim.dll for Windows and csim.mexglx for Linux).

Do a simulation with the standard parameters. Describe / explain the result. At which rates2 do the neurons fire?

Do a simultaion with I1=I2=18. I1 resp. I2 are external currents $ I_1$, $ I_2$ which are injected into the neurons. Describe the results. Why do the neurons not synchronize?

Do a simultaion with I1=I2=18, w = 30 resp. w=10. Describe the results. Describe the mechanism that leads to synchronization.

Do a simultaion with w=30, Tsim=5.0, I1=18 and I2=18.5 respectively I2=22. Tsim defines the duration of the simulation. Describe / explain the results.

Make some diagrams (think about well suited diagrams) which show quantitatively how the quality and speed of synchrony depends on which parameters. Describe / explain your approach and the results.

Examine how the results change if you add noise to the model (set the parameter Inoise $ > 0$). Describe / explain the results.


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Neural Networks B, SS06 1

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... SS061
Class Website:
... rates2
The vectors st1 and st2 contain all firing times of neuons 1 and 2.
... PSCs3
The PSCs are available in the vectors psc1 and psc2.

Joshi Prashant 2006-05-02