Left and middle: single-trial example of the generated signal (in blue) and its constitutive components (in red): instantaneous phase, frequency and amplitude, as well as an additive non-oscillatory and oscillatory response components; the left panel reflects a phase resetting plus frequency entrainment effect, while the middle panel corresponds to an additive oscillatory component. Right: real (filtered) magnetoencephalography data collected during passive viewing; the red curves are the analytically computed phase, frequency and amplitude (via the Hilbert transform).

genephys configuration hyperparameters.

Examples of two configurations based on phase resetting and frequency entrainment (left) and additive oscillatory responses (middle), shown together with results obtained from real data (right). At the top, temporal generalisation matrix (TGM) from standard decoding analysis; on the bottom, average evoked responses (ERP/F) for the sampled signal (blue) and its components (red), for the two stimuli (represented as different tonalities of blue or red).

Having more dimensions (channels) carrying stimulus-specific information, but with a larger degree of stochasticity, produces more realistic decoding patterns than having fewer dimensions with a lower degree of stochasticity. Here stochasticity referred to the channels’ probability of activation.

Oscillatory responses to stimulation occur in a diversity of frequencies and latencies across channels. Top row, single latency of response; bottom row, diverse latencies across channels; left column, single frequency; right column; diverse frequencies across channels.

An additive non-oscillatory response produces an slow expansion of decoding accuracy toward the end of the trial. A: By increasing the strength of the non-oscillatory response, the broadening of accuracy becomes more prominent. B: Changing the nature of the phasic relationship between the slower and the faster (oscillatory component) greatly changes the TGM, from all in-phase (left) towards all anti-phase (right).

Amplitude enhancement of the stimulus-relevant oscillation is not strictly necessary to produce realistic results, but it can enlarge the effects. Two features of the TGM are highlighted: the diagonal, and a vertical cut at the time point of maximum accuracy.

Example of real TGM, where the different characteristic features have been highlighted.

TGMs from six real data example subjects performing a passive viewing paradigm

Phase reset plus frequency entrainment effect. Top row, single latency of response; bottom row, diverse latencies across channels; left column, single frequency; right column; diverse frequencies across channels.