Changes in Cerebral Blood Flow With Spinal Manipulative Therapy vs. Voluntary Motion

Each subject will then undergo a baseline MRI in a head neutral position (0 degrees rotation). They will then be placed in head rotation (45 degrees) to the non-dominant and undergo a MRI. Maximum rotation to the side with MRI will follow. Finally, each subject will receive an upper cervical rotary manipulation to the non-dominant side with MRI immediately after. A total of 4 test conditions will be evaluated (rest, 45 degree, maximal, post-manipulation). The manipulation will be performed by an experience practitioner on a bed just outside the MRI room in supine position. A controlled impulse load will be applied and the head/neck returned to neutral position. Prior to each maneuver, the subject will be queried on their comfort, condition and willingness to continue