Abstract
The data emerging from the clinical and brain studies described above suggest that, in the case of OCD, there are two pertinent brain mechanisms that are distinguishable both in terms of neuro dynamics and in terms of the conscious experiences that accompany them. These mechanisms can be characterized, on anatomical and perhaps evolutionary grounds, as a lower level and a higher level mechanism. The clinical treatment has, when successful, an activating effect on the higher level mechanism, and a suppressive effect on the lower level one