Fig. 1.

Dark-rearing prevents the normal downregulation of the Cat-307 protein in primary visual, but not in primary auditory, cortex. Sections through layers IV and V of primary visual (A, B, C) and primary auditory (D, E, F) cortex from a 5-week-old normally reared (A,D), a 15-week-old normally reared (B,E), and a 17-week-old dark-reared (C,F) cat immunoreacted with Cat-307. Immunoreactive botrysomes are present in both the visual (A) and the auditory (D) cortices in the 5-week-old cat but absent from both areas by 15 weeks of age (B,E). Botrysomes are present in the visual cortex (C) after dark-rearing, but are not present in the auditory cortex (F) of dark-reared animals. Immunoreactive botrysomes can be found in all layers of area 17 of dark-reared animals in a pattern that is very similar to that observed in 5-week-old normal animals. Scale bar, 30 μm.