Figure 3.

AIS length maturation during visual cortex development. (A) The first AIS appeared at E14.5 often associated with Cajal-Retzius cells. AIS in presumptive cortical neurons increased in length until a maximum from P10-P15. Subsequently, a significant AIS length shortening occurred from the beginning to the peak of the CP in mice (P19–28). Beginning with the closure of the CP at P35, AIS length stabilized, persisting throughout adulthood (>P180). Similar observations were made for layer II/III and layer V neurons, with layer V AIS showing overall shorter length. (B) Longest AIS expansion in layer II/III neurons at P15 as indicated by ankG (green) and somatic NeuN (red). (B₁) Layer V image from the same cortical section as in (B). (C₁) Significant AIS length shortening in layers II/III in a P28 animal as compared to AIS length shown in (B). Layer V image from the same cortical section as in (C) with shorter AIS. Scale bars (B–C₁) = 25 μm. ^*p ≤ 0.05, standard deviation.