When I first speculated on the soul being the source of human free will, I did feel for many years that I was out on a limb, though I did not actively seek confirmation or denial to any great extent.
I then came across a full chapter on the subject in CS Lewis' book "Miracles" in which he went into much detail to reach a conclusion that a consciously invoked choice was a miraculous event because there could be no feasible material explanation.
Lewis' lack of sufficient information - it's difficult to allege a lack of imagination with the 'Alice' books in his output - isn't evidence FOR anything, it is at best a lack of validation of a proposition.
Now with the use of Google it is an easy matter to search for "souls and free will" to discover that there are many people who have reached the same conclusions as myself.
Have they done so on the same false dichotomy premise? 'I can't imagine material cause, therefore God' is not a valid argument - in the absence of evidence confirming one possibility, the response is 'I still don't know, I'll keep looking'.
And on the relationship with neurological matters, you can google "quantum indeterminacy and free will" to discover arguments for and against the possibility of indeterminate quantum events being the window for conscious freedom to interact within the otherwise physically predetermined material brain.
And unless something's significantly changed in the last few days, they'll all be Deepak Chopra levels of either failure to grasp the concept of quantum mechanics, or vast overreach from the quantum to the macroscopic - if you've a specific example I'm happy to look and face the possibility of being proven wrong.
Having said all this, I must say that the vast majority of people I meet consider their freedom to consciously choose as being a fundamental reality with no need to investigate how it works.
It's an assumption that works on a day to day basis - even thinking, academically, that it's not the case I still operate on a daily basis as though it were because our entire culture (maybe all cultures?) is predicated on the assumption that it is; personal responsibility, freedom of the individual, crime and punishment, high- and low-end supermarkets, multiple brands of... everything.
Like people's assumption, though, that gravity is a force, it's not supported by the evidence, and when it's taken out of the everyday examples it starts to break down, starts to no longer be a useful 'shorthand'.
O.