Fig. 2
From: Modeling brain connectivity dynamics in functional magnetic resonance imaging via particle filtering
The plot on top shows the causal dependency of area MT from area V1 for one of the 4 subjects in the visual task as an example of PF estimates of conditional dependency coefficients between time-series. Plot in the center shows the actual stimulation pattern as a square wave, where the presence and the absence of stimulation are represented by 1 and 0 respectively. The bottom plot shows a time shifted stimulation pattern, which has a half-period offset from the actual stimulation pattern. The t-test was run comparing connectivity values in correspondence of ones (stimulation ON) and zeros (stimulation OFF) in both cases. The second test allowed to exclude spurious changes in connectivity values not due to the stimulation