According to Professor Henry Markram, a digital model of brain is merely 10 years away. I've read a few books ( The Age of Spiritual Machines and The Singularity is Near ) by Ray Kurzweil, and it looks like he was pretty close when he predicted the date of the first model of the human brain. If I recall correctly, Kurzweil estimated that according to Moore's Law, the computing power required to run a simulation of a human brain would be achieved around the year 2020.
Of course I'm being optimistic in my reception of the news, but I can't help but be excited. I'm receptive to the idea that once we can realistically scan the human brain and create a realistic simulation based on that data, we can start to analyze and replicate human consciousness from a bottom up approach. I realize that there is a lot more to creating a true AI than merely simulating neurons, but it's a decent start on the path to a possible singularity. I realize that from a skeptic's point of view, Moore's Law is broken, but with advances being made in parallel programming, I believe that we can still achieve some phenomenal feats in regards to computing power. As Professor Markram could point out, as long as there are enough processors, a realistic number of neurons can be simulated.
The fact of the matter is that our knowledge of natural mechanisms is still very limited at this time. I'm sure that once we can model and analyze these mental processes, we can develop simpler algorithms to achieve the same behaviors. At that time, I expect us to make great inroads towards using subsets of these processes to accomplish tasks which seem impossible for computers to achieve now. Machine vision, fine motor skills, and many other domains would more than likely be drastically advanced using this technology. Again, the skeptic in me wants to debate the possibility of this actually occurring, but the optimist in me wants to realize the benefits this technology possibly offers. As with all matters this complex, there are many opinions, and only time will prove the correct parties right. Here's hoping to an AI that passes the Turing test within my lifetime!