Fig 3. Dendrogram-based groups of similar LFPs using Euclidian distance among trials.

Twelve similar clusters were formed out of the 100 trials both without (a) and with (b) circular phase shifting to account for network phase resetting due to light stimulus. The distance threshold that generates, for example, six clusters was about 62 arbitrary units without phase correction (a) and decreased to about 42 arbitrary units (b) after phase correction (see the horizontal dashed lines in a1 and b1). Panels a2 and b2 show two representative examples of LFP recordings belonging to two different clusters in the dendrogram. The recordings in panel a2 belong to the largest cluster whereas in b2 they belong to the second largest cluster in the dendrogram shown in panel b1. The LFP pattern classifier correctly separated dissimilar recordings in different clusters and also correctly placed in the same cluster similarly-looking LFPs.