The most frequent subsets of the neighbors of the left hippocampus (cut frequency value: 0.995).

413 subjects from the Human Connectome Project public release were examined. In all the subjects, the left hippocampus is connected to the following three ROIs: the Left-Putamen, Left-Thalamus-Proper and the lh.isthmuscingulate_3, and, therefore, to all 7 (= 23 − 1) non-empty subsets of those (the first 7 lines of the table). The lh.superiortemporal_2 ROI is connected to the left hippocampus in all, but one subjects, so its frequency is 412/413 = 0.99758. Note that no subset, containing lh.superiortemporal_2, may have a higher frequency than the frequency of lh.superiortemporal_2 alone, i.e., 0.99758. Indeed, all the 8 (empty and non-empty) subsets of the Left-Putamen, Left-Thalamus-Proper and the lh.isthmuscingulate_3, together with the lh.superiortemporal_2 is present in 412 out of 413 subjects, i.e., with 0.99517 frequency. The ROI lh.insula_2 is connected to the left hippocampus in 411 subjects out of the 413 subjects, therefore its frequency is 411/413 = 0.99517. Similarly, all the 8 subsets of the ROIs Left-Putamen, Left-Thalamus-Proper, and the lh.isthmuscingulate_3, together with lh.insula_2 have the same 411/413 = 0.99517 frequency. Theoretically, lh.insula_2, together with the lh.superiortemporal_2 may have the same frequency as lh.insula_2 alone (if the subject, where the left hippocampus—lh.superiortemporal_2 edge is missing is one of the two subjects where the left hippocampus—lh.insula_2 edge is missing), but this is not the case: the frequency of the neighbor set {lh.superiortemporal_2,lh.insula_2} is below the cut frequency value for Table 2, i.e., 0.995.