Certainly! I'm not arguing for any supernatural quality of consciousness. Instead I'm suggesting that free will may be defined as our (apparent) ability to influence the cycle of stimulus-response. We are (or at least I am) conscious, which seems best explained as a product of this cycle occurring. Consciousness may have a top-down influence that can affect the deterministic chain of events. I suppose the answer lies in whether or not we are responsible (even in part) for physical changes in the brain. Which seems hard to prove...

Edit: impossible to prove if we consider this a self-referential first order logical system