The results of fitting resp1 and resp2 with a stretched and scaled version of respS. Data show that the stretch factor increases with decreasing stimulus separation, confirming that the presence of a preceding stimulus increases the TTP and FWHM of the response. Furthermore, the fitted response amplitude decreases with decreasing stimulus separation, also in agreement with our experimental findings (Tab. 1). A residual fraction of 0.23 (on average for the three stimulus types) was observed if respS was directly subtracted from resp1, without stretching or scaling.