Transport properties in patterned isotropic high T c superconducting samples were investigated numerically and experimentally for boundary conditions imposing a nonhomogeneous current flow. Numerical simulations for the voltage distribution were based on a local nonlinear constitutive relation for the current density and the electric field, predicted by the vortex glass model extended to a nonhomogeneous current flow. In experiments the voltage drops at different sample locations were measured as a function of applied current, in a wide temperature range at low magnetic fields, and both the linear and the nonlinear regimes were examined. Our results support a local description, where long-range correlations in the millimeter scale are absent.