Steady state evoked potential (SSEP) responses in the primary and secondary somatosensory cortices of anesthetized cats: Nonlinearity characterized by harmonic and intermodulation frequencies
Fig 3
Exemplar logSNR at f1 = 23Hz depend on the vibration amplitude of F1 = 23Hz.
16 panels are arranged so that the row and column encodes the input amplitude of F1 = 23Hz (from 0 to 159μm) and F2 = 200Hz (from 0 to 16μm), respectively. (A) logSNR of S1 bipolar channel 131, whose location in the Utah array in (B) is identified with a blue diamond, (Session 2–2). This channel’s responses at f1 = 23Hz showed a significant main effect of F1 = 23Hz amplitude, but neither the main effect of F2 = 200Hz nor their interaction. p-value (F1, F2, interaction) = (<10−5, 0.054, 0.52) with the corrected threshold 0.00019. y-axis of each subplot is the mean logSNR with standard deviation across 15 trials. x-axis is the response frequency f, around f = 23Hz. Note that, as we considered a set of frequencies F’ = {f | f-3<f’<f-1 or f+1<f’<f+3} as the neighboring frequencies for the logSNR computation, logSNR is smoothed and has a lower spectral resolution than the half bandwidth of 0.5Hz. (B) Spatial mapping of logSNR at f1 = 23Hz across all channels in S1 (Session 2–2). Each square represents one of the bipolar re-referenced channels. The center of the square is plotted at the middle point between the original unipolar recordings of the 10x10 array. Squares with gray indicate channels, which were removed from the analysis (see Methods).