(A) Polar orientation maps recorded in a ferret using chronic optical imaging at the postnatal ages shown (in days; reprinted from ). (B) GCAL model polar orientation maps. Spontaneous activity patterns drive the map development until 6000 image presentation iterations, after which natural images are presented to the model retina. (C) Patterns of connectivity from the LGN to 7 arbitrarily selected V1 neurons, showing how orientation selectivity emerges over time. Both the ferret and model map have a ring shaped FFT (inset in the final map plot of A and B).