Fig 9. Robustness to small samples.

Frequencies of the maximum PAC value, with four methods: a DAR model with (p, m) = (10, 1), the GLM-based model from Penny et al. [22], and two non-parametric models from Tort et al. [23] and Ozkurt et al. [26]. Each point corresponds to one signal out of 200. Kernel density estimates are represented above and at the right of each scatter plot. From left to right, the simulated signals last T = 2, 4 and 8 seconds. The signals are simulated with a PAC between 3 Hz and 50 Hz. The DAR models correctly estimate this pair of frequency even with a short signal length, as well as the GLM-based metric [22], while the two other metrics [23, 26] are strongly affected by the small length of the signals, and do not estimate the correct pair of frequency.