A.I. research can't really advance until we have a thorough understanding of natural intelligence first. You could say that the A.I. research thread is waiting for the results from the neurology research thread to finish. The first A.I. will probably be just a dumb software emulation of neurological and biological properties and behaviors, just running on whatever super-fast processors we have at the time. Maybe quantum computers (which may be necessary to emulate certain biology.)