Free will and neuroscience

In honor of Rabbi Shalita
In one of Haim Sompolinsky's lectures, he claims that they conducted an experiment on cancer patients, and by electrical stimulation in certain areas they were able to make them want to move their hand, and in some cases they moved their hand without any feeling of will. Of course, the experiment needs to be tested on its own and there could be many problems with it, but if this is indeed the case, then it seems that the very desire to act stems from brain processes. Isn't this a contradiction to free will, after all, the essence of free will is that man is the creator of desires and every action begins with the will of the soul, and here we have proof that the will itself stems from brain processes?