Our understanding of biological systems is progressing much faster, in my opinion, than our ability to artificially replicate complex biological functions (i.e. most brain functions) through computer technology, engineering, and/or robotics. Therefore it is likely that complex AI would very likely be biological in nature (i.e. be composed of living tissue and organ systems) that is attached electrically, optically, or in some other form with robot-like artificial limbs and such. In fact, even these robotic parts may be composed of complex biological elements such as skin and muscle.
Too much use of complex, but you get the idea.