Fig. 3.

The surplus removal of synaptic terminals in β2m^-/- mice is preferentially directed toward clusters of nerve terminals. Graphs show the distribution of distances between nerve terminals along the cell soma membrane of motoneurons. The distances are calculated in percentage of total soma membrane length of the neuron in the nuclear plane. In unlesioned motoneurons, the intervals between nerve terminals are very similar in mutant and wild-type animals (a and b). In lesioned motoneurons at 1 week after axotomy, there is a distinct difference between the two groups of animals with a much more prominent loss of closely spaced terminals in β2m^-/- mice compared with wild-type mice (c and d). The schematic drawing in e summarizes the main differences in the synaptic removal process between wild-type and β2m^-/- mice.