Fig. 5.

Decline in immunostaining for NMDAR1 in layer 4 with progressive development compared in cat (top) and ferret (bottom) visual cortex. Intensely immunoreactive cells are visible both in layers 4 and 2/3 in P52 cat (A) and in P49 ferret (C). At these ages, cells in layers 5 and 6 are much less intensely immunoreactive than cells in layers 2/3. By the end of the cat critical period (B) (P76) and in adult ferrets (D), this intense immunoreactivity persists in layers 2/3 but is gone from layer 4; cells in layer 4 exhibit staining similar to that found in the lower layers. Scale bar, 300 μm.