Formation of synfire chains (Jun and Jin 2007)

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"Temporally precise sequences of neuronal spikes that span hundreds of milliseconds are observed in many brain areas, including songbird premotor nucleus, cat visual cortex, and primary motor cortex. Synfire chains—networks in which groups of neurons are connected via excitatory synapses into a unidirectional chain—are thought to underlie the generation of such sequences. It is unknown, however, how synfire chains can form in local neural circuits, especially for long chains. Here, we show through computer simulation that long synfire chains can develop through spike-time dependent synaptic plasticity and axon remodeling—the pruning of prolific weak connections that follows the emergence of a finite number of strong connections. ..."
1 . Jun JK, Jin DZ (2007) Development of neural circuitry for precise temporal sequences through spontaneous activity, axon remodeling, and synaptic plasticity. PLoS One 2:e723 [PubMed]
Model Information (Click on a link to find other models with that property)
Model Type: Realistic Network;
Brain Region(s)/Organism:
Cell Type(s):
Gap Junctions:
Simulation Environment: C or C++ program;
Model Concept(s): Temporal Pattern Generation; Spatio-temporal Activity Patterns; STDP; Vision;
Implementer(s): Miller, Aaron [aaron at];
/* Minimal  random number generator of Park and Miller with Bays-Durham shuffle and added safeguards. Returns a uniform random deviate between 0.0 and 1.0 (exclusive of the endpoint values).
Call with idum a negative integer to initialize; thereafter, do not alter idum between successive deviates in a sequence. RNMX should approximate the largest  oating value that is less than 1.*/

#define IA 16807
#define IM 2147483647
#define AM (1.0/IM)
#define IQ 127773
#define IR 2836
#define NTAB 32
#define NDIV (1+(IM-1)/NTAB)
#define EPS 1.2e-7
#define RNMX (1.0-EPS)

float ran1(long *idum) {
  int j;
  long k;
  static long iy=0;
  static long iv[NTAB];
  float temp;

  if (*idum <= 0 || !iy) {  			// Initialize.
    if (-(*idum) < 1) *idum=1; 			// Be sure to prevent idum = 0.
    else *idum = -(*idum);
    for (j=NTAB+7;j>=0;j--) {  			// Load the shu e table (after 8 warm-ups).
      if (*idum < 0) *idum += IM;
      if (j < NTAB) iv[j] = *idum;
  k=(*idum)/IQ; 				// Start here when not initializing.
  *idum=IA*(*idum-k*IQ)-IR*k; 			// Compute idum=(IA*idum) % IM without overflows by Schrage s method.
  if (*idum < 0) *idum += IM;
  j=iy/NDIV; 					// Will be in the range 0..NTAB-1.
  iy=iv[j]; 					// Output previously stored value and refill the shuflle table.
  iv[j] = *idum;
  if ((temp=AM*iy) > RNMX) return RNMX; 	// Because users don't expect endpoint values.
  else return temp;

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