  We present a general stochastic Liouville theory of electrical transport
across a barrier between two conductors that occurs via sequential hopping
through a single defect's spin-0 to spin-1/2 transition. We find
magneto-conductances similar to Hanle features (pseudo-Hanle features) that
originate from Pauli blocking without spin accumulation, and also predict that
evolution of the defect's spin modifies the conventional Hanle response,
producing an inverted Hanle signal from spin center evolution. We propose
studies in oblique magnetic fields that would unambiguously determine if a
magnetoconductance results from spin-center assisted transport.
