Figure 6. Segmentation of single-trials belonging to the structured sequence into voltage configurations (‘momentary states’).

Each of these states is labeled in a gray scale gradation. The trials length (right-padded in black) is marked by a vertical line. For each subject (panel a and panel b), and each day (from left to right, day 1 and day 2 respectively), we show a series of exemplar single trials and the segmentation provided by the HMM algorithm. It should be noted that during day2 the average duration of these states is comparably longer that that during day 1 in both subjects. This observation was confirmed statistically in both subjects. The difference in duration length between day 1 and day 2 was highly significant and only during the structured sequence. This evidence provides new insight about spatio-temporal properties of neural activity underlying sequence-learning.