Dear Björn & Frank,

sorry, I was very busy these days.

Regarding 2 and 3)
As you pointed out I could confirm that EPSPs will be 150% the size,  
if the input of the static synapse arrives 5ms compared to 10ms before  
the input of the plastic synapse.
To this end, I set the firing threshold high (0mV) to prevent spiking  
and averaged the difference of the maximum and minimum membrane  
potential.
I checked the configuration of the chip, the configurations are  
identical for both cases. As expected, in the raw configuration data  
the only difference is the time stamp of the first input spike.
This suggests that we see an effect caused by analog electronics.

To get more insights, I would like to recommend the following steps.
As noted above turn off spiking and compare the height of EPSPs for  
different timings of input spikes:
1) is this behavior affected by the interval between the input spikes  
-> plot the relative difference of EPSP sizes over the timing of the  
first spike
2) is this behavior affected by the absolute timing of the input  
spikes -> plot the relative difference of EPSP sizes over the timing  
of the first spike (while keeping the interval to the second spike  
constant)
3) is this behavior affected by the type of synapses -> replace the  
plastic synapse by a static one

Regarding 4)
The larger the value passed to setIcb, the shorter the refractory  
period. If not required for the functionality of your network, please  
use the standard value (but not calling this function).
As Eric pointed out autoSTDPFrequency controls the frequency of weight  
updates. If not configured manually by this function the maximal  
frequency is used.

Kind regards,

Thomas

P.S. consider looping experiments inside slurm jobs to improve the  
performance of your scripts


Zitat von Eric Mueller <[log in to unmask]>:

> Hey Bjoern & Frank,
>
> sorry for the late answer & the expert questions will be
> answered by Tom ;).
>
> Back to the problems:
>
> On Fri, Oct 30, 2015 at 12:14:44PM +0000, Deiseroth, Bjoern wrote:
>> 1)
>> The Script attached seemingly has messed up the environment.  
>> Running an arbitrary python script results in the following error.
> Nope, it's the "copy.py" file that was located in the same directory
> ;)... I renamed it and now it works again.
>
>> 2) + 3)
> => Tom... :/
>
>>
>> 4)
>> I wanted to play a little with hwa.setIcb and hwa.autoSTDPFrequency  
>> as I don't know how exactly they influence the network, but can't  
>> right now..
>> Can you explain setIcb? Will dig again into the paper to understand  
>> the STDP Controller..
> * setIcb controls the neuron refactory period in a non-linear way  
> (=> Andi, can
>   you comment on that?).
> * autoSTDPFrequency controls the frequency of weight updates (the
>   STDP's causality/acausality is stored locally in the synapse but the
>   udpate happens digitally with a certain frequency)
>
>
> ciao
> Eric
> --
> gggqGZZ
>
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