NCMIC Group, Inc.

The investigators are performing a study to determine whether changes in blood flow occur in the neck and back of the brain following a series of head positions and a manipulation of the upper neck. Each participant will be asked to undergo a series of MRI's to evaluate whether there are any changes in blood flow resulting from any of the head positions or manipulation. The study will be conducted over a period of 1 day and each participant can anticipate the testing to take approximately 120 minutes.