Figure 13. Classifying retinal ganglion cells without visible light information.

(a) Multielectrode arrays record a 2D projection of spatio-temporal action potentials, called electrophysiological images (EIs), and schematically illustrated here for a midget (left) and a parasol (right) RGC. Differences in cell morphology lead to differences in the EIs. (b) Examples of handcrafted filters that can extract discriminative features of EIs, such as amount of rotation, number of radial processes, diameter, velocity of propagation of the axonal action potential in the EI. Classifiers can be trained to recognize cell types using these features. Adapted from [126].