With a dual-state paradigm, such as those involving power changes on oscillatory activities, one is interested in the change in power from a baseline time period to an active time period. These periods are denoted as vectors of time samples, tbase and tact, respectively. In this case: Pˆbaser=wTrRbasewrPˆactr=wTrRactwr where Rbase is the covariance of the baseline period and Ract is the covariance of the active period. To improve numerical stability, dopt(r) and w(r) are computed using the average covariance of the active and baseline period, i.e., substituting R = (Rbase + Ract) / 2. Note that tbase must be the same length as tact. The contrast between Pˆactr and Pˆbaser can then be expressed as an F-ratio [dB] [49]: FdBr=10log10PˆactrPˆbaser
