Local electrical conductivities were measured for plastically deformed n-GaN single crystals by scanning spreading resistance microscopy (SSRM). In the SSRM images, many spots with high conductivity were observed, which can be attributed to introduced edge dislocations whose line direction is along [0 0 0 1] and Burgers vector is b = (a/3)[1 2¯$\bar{2}$ 1 0]. This result is in contrast to the previous studies which showed that grown-in edge dislocations of the same type in GaN films exhibit virtually no conduction. This suggests that the dislocation conduction depends sensitively on the dislocation core structure. Current-voltage spectra indicated a Frenkel-Poole mechanism for the conduction.