[1] Mayo Clin, Neuroinformat Lab, Rochester, MN USA
[2] Mayo Clin, Dept Neurol Surg, Rochester, MN USA
[3] Karolinska Inst, Dept Clin Neurosci, Stockholm, Sweden
[4] Mayo Clin, Dept Neurol Surg, Jacksonville, FL USA
[5] Mayo Clin, Dept Radiol, Jacksonville, FL USA
[6] Lowenstromska Hosp, Capio Spine Ctr Stockholm, Box 2074, S-19402 Upplands Vasby, Sweden