Measurement of the number of boutons at varying distances along the axon from the soma in the slice
Figure 14. Cumulative counts of the number of presynaptic boutons at varying distances from the soma reveal approximately 150 boutons within one length constant, and 260 within 2 length constants. However, the later is probably a gross underestimate because axons are terminated abnormally early in the slice owing to cutting. The numbers in full axonal arbors in vivo are much likely considerably higher (see previous slide).