Neuroscience- the New Philosophy (Week 2)

The matter of neurology and psychiatry is coming more to light, all these different approaches show a different perspectiv such as the evolutionary theory, which has always been there, but only recent scientists approached this matter from the darwinian standpoint. Especially called as evolutionary neuro-psychiatry. I was wondering why this hasn't been approached before, MRI ad PET scan were found a long time ago and  scientists already knew than that the different scans can show the inactive/ active parts of the brain. A classic example used is that people with a classic psychological disturbance,such as Hysteria are seen with a mental illness, that illness is seen strictly medical, as the person developed a paralysis of his arm or leg, when you then test the patient in neurological terms, such as MRI or PET scans there are no deficits, nothing seems to be wrong, however where does these symptoms the patient claims to have, come from? Things like hysteria have been examined many many times, and mainly it is assumed that it comes from previous experienced emotional traumas that are impede him from moving arm or leg. So is that how we are going to explain mental illness these days? One particular word was stuck in my head for the last week, epiphenomenalism, which i didn't understand at first but than, it means that the individuals willingness in the brain is like a shadow that always accompanies you, but is never the cause.