Those
neural signaling patterns, in Pitkow and Angelaki's description, are then recoded into another
set of patterns; that process sorts out the important variables in the environment from those that don't matter.
John «Jack» Pettigrew, then a young medical student in Canberra, Australia, noted this fact in the mid 1960s, reasoning that the
neural mechanism for stereopsis must entail another
set of binocular neurons, ones that
signal retinal disparity by processing noncorresponding retinal points.