Thursday, June 25, 2020

Introduction

In the NEST Meeting on May 25th there was a very interesting discussion of handling of delays in NEST, with focus on STDP models. It became obvious, that this topic requires a more in-depth discussion and it was decided to do a separate VC for this discussion.

Reference Materials

Relevant background reading is the following article

• Phenomenological models of synaptic plasticity based on spike timing, Abigail Morrison, Markus Diesmann & Wulfram Gerstner; Biological Cybernetics volume 98, pages 459–478 (May 2008), doi: 10.1007/s00422-008-0233-1
• Slides t.b.a.?

Agenda

• Brief introduction of key speakers (if necessary)
• Introduction into the topic
• Discussion
• Conclusions

Introduction to the topic

Bruno Golosio presented an overview and current work on a prototype implementation of different handling of delays. The impact on STDP weight updates was investigated and different mechanisms for handling spike event were suggested.

Discussion

• processing of information on pre- and post-synaptic side distributed to different compute nodes
• effect of the timing of weight updates
  • difference of axonal/dendritic delays
  • mechanisms of weight normalization
• implementation proposal of spike-buffers
• effect of spike delivery times on the simulation speed
• numeric precision of implementations, GPU vs CPU

Conclusions

• the discussed ideas will be looked at further
• possibilities to realize the implementation also with MPI will be investigated
• we will schedule another meeting in a couple of weeks