Fig. 6.

(A–D) Spatial frequency bandwidth of the BCM, NBCM and ICA receptive fields. The BCM (A) and NBCM (B and C) algorithms produce receptive fields with similar spatial frequency bandwidths, and these are a good match for the bandwidths measured for cat and macaque V1 neurons (De Valois et al., 1982a; Tolhurst and Thompson, 1981), which average 1.5 octaves (marked by dotted line). ICA (D) produces receptive fields with somewhat lower spatial frequency bandwidth. (E–H) The standard BCM algorithm (E) produces receptive fields which are very long and thin, and this is reflected in their low orientation bandwidths. The NBCM and ICA algorithms (G and H) produce less extended receptive fields, and as a result, their orientation bandwidths are a better match for the bandwidths measured for macaque V1 by (De Valois et al., 1982b), which averaged 40° (dotted line).