TABLE 1.

Summary of results of comparisons between complex cell receptive fields and subunits (A) and comparisons between complex cell subunits and simple cell receptive fields (B)

A. Comparisons of complex cell receptive fields and their subunits
Spatial extentsāœ“Receptive fields are slightly larger (mean area ratio = 1.2)
Spatial shapeāœ“Receptive fields are slightly more circular than subunits
Response maps for bright and dark referencesxResponse strengths can be imbalanced (e.g., Fig. 17, C and D)
Center positions can be different (e.g., Fig. 17D)
B. Comparisons of complex cell subunits and simple cell receptive fields
Spatial extentsāœ“Similar
Number of subregionsxComplex cell subunits have more subregions than simple cells
Spatial shapexEnvelopes of simple cell receptive fields tend to be elongated more horizontally than vertically (e.g., Fig. 14, Cā€“F and J)
  • Subsection A summarizes comparisons between subunits and receptive fields to examine the minimal model for complex cells. Subsection B summarizes comparisons between complex cell subunits and simple cell receptive fields to examine whether they are equivalent to each other. The comparison of spatial extents is based on length, width, and areal size, whereas the comparison of spatial shape is based on aspect ratios, length-to-width ratios, and the orientation of elongation. Brief comments and relevant examples are given in the right column.