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SUMMARY:The role of degree distributions in shaping the dynamics in networ
 ks of sparsely connected spiking neurons 
DTSTART:20101105T121500
DTSTAMP:20260916T202707Z
UID:213c7afb17cc7148d10cd0f69f78a69297afb5fba9c921a339697f6f
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Alex ROXIN\nMost work on sparsely connected networks of sp
 iking neurons has made use of the assumption that there is a fixed probabi
 lity of connection between any two neurons. This results in narrow in-degr
 ee and out-degree distributions\, i.e. all neurons receive and send out ab
 out the same number of connections. This allows for powerful mean field te
 chniques to be applied making such standard random networks attractive for
  analytical work. However\, recent electrophysiological work indicates tha
 t local cortical circuits exhibit statistical regularities not consistent 
 with a standard random network. I will discuss how changes in the network 
 connectivity\, specifically in the degree distributions\, affect the dynam
 ics in networks of sparsely connected spiking neurons. For the case of the
  incoming connections\, the effect of degree distribution can be accounted
  for in a modified rate equation in which the degree is treated as a conti
 nuous\, pseudo-spatial variable. This allows one to calculate fixed point 
 solutions and their stability using standard techniques.\n\nI will show ho
 w varying the degree distribution shifts stability boundaries of the async
 hronous state to oscillations and compare analytical results to full netwo
 rk simulations.\n\nI will show how broadening the out-degree increases pai
 rwise correlations in subthreshold currents. In the asynchronous regime\, 
 fluctuations in the excitatory and inhibitory currents dynamically balance
  leading to near-zero spike correlations\, independent of out-degree. When
  oscillations are present however\, the out-degree has a significant effec
 t on spiking correlations and can qualitatively alter the dynamical state 
 of the network. 
LOCATION:BC 01 https://plan.epfl.ch/?room==BC%2001
STATUS:CONFIRMED
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