Figure 5

Microtubule distribution at dendritic branch points.

(a) The number of microtubules is linearly correlated with dendritic cross sectional areas. Black circles indicate spiny dendrites and white circles indicate aspiny dendrites. (b – f) Serial FIB/SEM images of a dendrite (10 nm pitch, 5 nm lateral resolution). The same microtubules can be traced from section to section easily. Scale bar, 0.5 µm. (g – j) Serial FIB/SEM images of a bifurcated dendrite (300 nm pitch, 5 nm lateral resolution). The mother dendrite (g) gradually changes shape (h, i) and bifurcates into two daughter dendrites (arrows, (j)). Scale bar, 1 µm. k, A 3D reconstruction of the bifurcated dendrite shown in (g – j). (l) Traces of the microtubules observed in the bifurcated dendrite shown in (k). Microtubules present in the mother dendrite run into one of the two daughter dendrites