Prior to obtaining the magnetic resonance image (MRI), the TMS motor location and motor threshold was determined. Using the 5-cm rule, a putative prefrontal location was also determined. Subjects wore swim caps, and Vitamin E capsules were taped to the cap over these two locations. MRI scans were then stored at a central site and analyzed for distance (atrophy) and location. Manual method of determining distance (MEDX) The image is oriented using standard AC-PC alignment. In a coronal

view, measurement is made from scalp to closest cortical surface. Multiple measurements Inhibitors,research,lifescience,medical are taken and averaged from the several coronal slices containing the fiducial. The appropriate power needed to stimulate the prefrontal click here cortex (PFC) with the same intensity as the motor cortex (taking distance into account) is given by: PFC power needed = 100*(EXP[(0.036)*(DPFC-DMotor)]) (Figure 1) and (Figure 2) illustrate how the distance Inhibitors,research,lifescience,medical to cortex is measured manually over the motor and prefrontal cortex. Figure 1 Manual

measurement of Inhibitors,research,lifescience,medical distance to cortex. Figure 2 Manually determining whether the PFC is in the appropriate position. PFC, prefrontal cortex. Determining whether the prefrontal cortex Is In the appropriate position In standard AC-PC alignment, if no temporal lobe is seen in a coronal slice, the fiducial is considered to be appropriately over PFC (Figure 2, left panel). Inhibitors,research,lifescience,medical If a small amount of temporal lobe is seen, the image is examined from other views. If it is still uncertain whether the fiducial is over the Inhibitors,research,lifescience,medical PFC, the PFC spot is moved 6 cm forward from the motor spot. If a large amount of temporal lobe is seen in the coronal slice, the PFC is automatically moved forward. This method is limited due to variability

in PFC anatomy and is dependent upon the rater’s skill. Determining whether the prefrontal cortex Is In the appropriate position-automated method (Figure 3) (next page) shows the automated method. too Figure 3 Automated method for determining PFC position. PFC, prefrontal cortex. Results Imaging data are available for the first 20 subjects enrolled. Prefrontal distance (Figure 4) shows the results. Figure 4. Prefrontal distance for the first 20 subjects. PFC, prefrontal cortex Prefrontal location Prefrontal location Using the anatomic landmark method, the “5-cm rule” resulted in 8/20 (40%) subjects with stimulation that would have occurred over the premotor cortex, and that needed to be moved 1 cm forward. We are still testing the automated method.