elephant.spike_train_correlation.spike_time_tiling_coefficient

elephant.spike_train_correlation.spike_time_tiling_coefficient(spiketrain_i, spiketrain_j, dt=array(0.005) * s)[source]

Calculates the Spike Time Tiling Coefficient (STTC) as described in [1] following their implementation in C. The STTC is a pairwise measure of correlation between spike trains. It has been proposed as a replacement for the correlation index as it presents several advantages (e.g. it’s not confounded by firing rate, appropriately distinguishes lack of correlation from anti-correlation, periods of silence don’t add to the correlation and it’s sensitive to firing patterns).

The STTC is calculated as follows:

STTC = 1/2((PA - TB)/(1 - PA*TB) + (PB - TA)/(1 - PB*TA))

Where PA is the proportion of spikes from train 1 that lie within [-dt, +dt] of any spike of train 2 divided by the total number of spikes in train 1, PB is the same proportion for the spikes in train 2; TA is the proportion of total recording time within [-dt, +dt] of any spike in train 1, TB is the same proportion for train 2. For TA = PB = 1 the resulting 0/0 is replaced with 1, since every spike from the train with T = 1 is within [-dt, +dt] of a spike of the other train.

This is a Python implementation compatible with the elephant library of the original code by C. Cutts written in C and avaiable at: (https://github.com/CCutts/Detecting_pairwise_correlations_in_spike_trains/ blob/master/spike_time_tiling_coefficient.c)

Parameters:
spiketrain_i, spiketrain_j: neo.SpikeTrain

Spike trains to cross-correlate. They must have the same t_start and t_stop.

dt: pq.Quantity.

The synchronicity window is used for both: the quantification of the proportion of total recording time that lies [-dt, +dt] of each spike in each train and the proportion of spikes in spiketrain_i that lies [-dt, +dt] of any spike in spiketrain_j. Default : 0.005 * pq.s
Returns:
index: float or np.nan

The spike time tiling coefficient (STTC). Returns np.nan if any spike train is empty.

Notes

Alias: sttc

References

[1]Cutts, C. S., & Eglen, S. J. (2014). Detecting Pairwise Correlations in Spike Trains: An Objective Comparison of Methods and Application to the Study of Retinal Waves. Journal of Neuroscience, 34(43), 14288–14303.