Joshua Karpf

Abstract The brain-wide burden of MR-visible perivascular spaces (PVS) is age-dependent in rhesus macaques. Automated quantification in 94 male and female animals ranging 5–28 years of age demonstrated a robust association of age with PVS count and volume, and an anatomical distribution paralleling that of humans. Preliminary ex vivo microscopy confirmed that an MRI-detected tubular structure corresponded to a perivascular space.

Figure S1. Representative images of Golgi-Cox-stained mouse PD7 CA1 pyramidal neurons (scale bar 50 μm). Neurolucida tracings of the same neurons are shown in Figure 1A. Figure S2. (A) 100x images of Golgi-Cox-stained secondary apical adult (PD > 365; left image) and neonatal (PD7, right image) dendrites from CA1 pyramidal neurons. The neonatal dendrite exhibits fewer, less developed spines than the adult. Mature (adult) and immature (PD7) spines are indicated with white arrows.

Abstract Major developmental events occurring in the hippocampus during the third trimester of human gestation and neonatally in altricial rodents include rapid and synchronized dendritic arborization and astrocyte proliferation and maturation. We tested the hypothesis that signals sent by developing astrocytes to developing neurons modulate dendritic development in vivo.