Figure 2. Synapse detection by classification of neurite interfaces.

(a) Definition of interfaces used for synapse classification in SynEM. Raw EM data (left) is first volume segmented (using SegEM, Berning et al., 2015). Neighboring volume segments are identified (right). (b) Definition of perisynaptic subvolumes used for synapse classification in SynEM consisting of a border (red) and subvolumes adjacent to the neurite interface extending to distances of 40, 80 and 160 nm. (c) Example outputs of two texture filters: the difference of Gaussians (DoG) and the intensity/variance filter (int./var.). Note the clear signature of postsynaptic spine heads (right). (d) Distributions of int/var. texture filter output for image voxels at a synaptic (top) and non-synaptic interface (bottom). Medians over subvolumes are indicated (arrows, color scale as in b). (e) SynEM flow chart. Scale bars, 500 nm. Scale bar in a applies to a,b.

DOI: http://dx.doi.org/10.7554/eLife.26414.005