Figure 2.

The amount of apoptosis visualized depends on phagocytosis efficiency. The net apoptotic cell number observed (net apoptosis) at a given time point depends on the rate of live neurons undergoing apoptosis (input) and the rate of clearance of the apoptotic cells by microglia (output). (A) In a perfect scenario, the rate of phagocytosis would be comparable to the rate of apoptosis induction, and no apoptotic cells should be observed. (B) In most cases, apoptosis induction is faster than engulfment and degradation, and only some apoptotic cells would be observed, whereas others are already cleared by microglia. (C) In a dysfunctional scenario with deficient phagocytosis, all cells undergoing apoptosis would be visible.