Basis profile curve identification to understand electrical stimulation effects in human brain networks
Fig 3
Technique for identification of basis profile curves (BPCs).
An illustration of the series of steps to extract BPCs from the voltage matrix V and subgroup assignments k ∈ n. A: Within stimulation-pair subgroup self-projections (all trials are projected into one another). B: Between-subgroup cross-projections. C: An illustration of sets of cross- and self-projections for stimulation-pair subgroup 11, S11,m. D: The significance of each set Sn,m is determined initially by t-value vs. zero. Negative t-values are set to zero. The matrix of these values is then scaled to 1, and labeled Ξ. E: Non-negative matrix factorization (NNMF) is performed to identify structure. F: The inner dimension of NNMF is iteratively reduced. G: BPCs are identified from the groups clustered in the rows of H.