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.

The goal is to further investigate the cerebrovascular hemodynamic consequences of cervical spine positions, including rotation and manipulation in-vivo under clinically relevant circumstances using two advanced forms of MRI technology on the VA and posterior cerebral vessels. According to the knowledge of the investigators, a study utilizing MRI and functional blood oxygen level dependent (fBOLD) imaging to examine blood flow and perfusion, turbulence and evidence of micro-trauma within these vessels has yet to be conducted.

Inclusion/Exclusion Criteria

1. Enrolled and matriculated as a student in the Canadian Memorial Chiropractic College.
2. Healthy asymptomatic male patients who would otherwise receive cervical manipulation on a regular basis as a part of their normal learning experience and will have had a cervical manipulation in the last 3 months.
3. Sufficient English language ability to complete study questionnaires (see appendix).
4. No history of disabling neck, arm or headache pain within the last 6 months.
5. No current or prior history of neurological symptoms including, facial or extremity weakness, abnormal sensation to the face, body or extremities, uncontrolled movements, abnormal gait, dizziness, unexplained nausea/vomiting, difficulty with speaking or swallowing.
6. Subjects will have had no prior history of head trauma or prior history of surgery to the neck region.
7. No history of claustrophobia, metallic implants or tattoos to ensure compatibility with MRI requirements.