Multichannel Systems NeuroExplorer - Manual (Page 92)

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Algorithm
For each spike train, NeuroExplorer creates a new Interval variable and stores all the burst intervals
in this variable.
MaxInterval method
Find all the bursts using the following algorithm:
Scan the spike train until an interspike interval is found that is less than or equal to Max. Interval
.
While the interspike intervals are less than Max. End Interval, they are included in the burst.
If the interspike interval is more than Max. End Interval, the burst ends.
Merge all the bursts that are less than Min. Interval Between Bursts apart.
Remove the bursts that have duration less than Min. Duration of Burst or have fewer spikes
than Min. Number of Spikes.
Surprise method
1) First the mean firing rate ( Freq ) and mean interspike interval ( MeanISI ) of the neuron are
calculated.
Freq = NumberOfSpikes / (FileEndTime – FileStartTime)
MeanISI = 1 / Freq
2) NeuroExplorer scans the spike train until it finds two sequential ISI's so that each of those ISIs is
less than MeanISI/2. The surprise of the resulting 3-spike sequence is calculated:
If we assume that a random variable P has a Poisson distribution with parameter Freq and we also
assume that the burst has N spikes and the distance from the first to the last spike of the burst is T,
then the surprise of the burst is:
S = - log10 (Probability that P has at least N points in a time interval of length T )
3) NeuroExplorer adds the spikes to the end of the burst until the first ISI that is more than MeanISI
and calculates surprise for each of the bursts (with 3 initial spikes, 4 spikes, 5 spikes, etc.) The burst
with maximum surprise Smax is then selected.
4) NeuroExplorer removes the spikes from the beginning of the burst and calculates the surprise for
each of the reduced bursts. The burst with maximum surprise Smax is then selected.
5) If Smax is more than MinSurprise and the number of spikes in the burst is more than 3,
NeuroExplorer adds the burst to the result.
Reference
Legendy C.R. and Salcman M. (1985): Bursts and recurrences of bursts in the spike trains of
spontaneously active striate cortex neurons. J. Neurophysiology, 53(4):926-39.
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