Figure 5
Grid of spectral Granger causality maps in the frontal-parietal-occipital loop. The colormap is presented in baseline standard deviation units (how many times a GC is greater or lesser than the baseline standard deviation). The lines in figure grid represent the cortical structures were the information was originated, while the columns represent the target structures (GC direction is defined from the structure that originates the information to target structure). The instant t = 0 s (dashed white line) is defined as the instant that the animal reaches the central nose poke, and thus, experience the maximum vibrissae deflection. The vertical black dashed lines divide the figures in the task periods (anticipatory – green 1, discrimination 1 – light blue 2, discrimination 2 – dark blue 3, response – red 4 and reward – yellow 5), and the horizontal lines divide the figure in frequency bands (theta 4–12 Hz, beta 1 [13–21 Hz], beta 2 [22–30 Hz], gamma 1 [31–65 Hz] and gamma 2 [66 to 100 Hz]). Absolute GC variations from the baseline, higher than two times the baseline standard deviation, were considered significant. The figures in the grid diagonal show the significant regions of the spectral GC maps. Each diagonal figure brings information about the three other GC maps at the same line. The colored regions indicate the significant map regions, where red represents the first map that appears in that line grid (left to right), green the second and blue the third. If a region was significant in more than one map, the color of the maps should be overlayed (maps 1 and 2 = yellow; maps 1 and 3 = magenta; maps 2 and 3 = cyan; maps 1, 2 and 3 = white). The maps reveal both top-down and bottom-up directed influence, which was stronger and time-frequency specific during active tactile discrimination task. Spectral GC values were estimated with a 150 ms window running in 10 ms time steps.
