Neural correlates of sparse coding and dimensionality reduction
Fig 7
NMF recovers a sparse and parts-based representation of olfactory perceptual space.
(A) Waterfall plot of the 10 basis functions constituting W (same nomenclature as in Fig 4). (B) Heat map of the hidden coefficient matrix, H, in which each column of H corresponds to a different odor. Columns of H are normalized and sorted. (C) Plot of all 144 odors in the dataset (each point is a column in H) in the space spanned by the first three basis functions, (“fragrant”/“floral”),
(“woody, resinous”/“musty, earthy”), and
(“fruity, other than citrus”/“sweet”). Black, red, and blue points are those with their largest hidden coefficient corresponding to the first, second, and third basis function, respectively. Gray points are all remaining odors. Adapted with permission from [48].