Figure 1.

Comparison of structure and function in early vs. senescent astrocytes. The structure of astrocytes during physiology (left) is not severely changed upon aging, except for the moderately increased thickness of the appendages (right), with at least partial maintenance of their contacts to adjacent cells (not shown). The marked differences concern functions listed on the left and right sides. The state of senescent astrocytes depends primarily on changes in their gene expression, specifically on downregulation of genes governing physiology (examples to the left) and upregulation of genes governing new functions or increasing their activity during and upon aging (examples to the right). The present astrocyte images are analogous to those of [23].