[1] Univ Calif Los Angeles, Sch Med, CURE Digest Dis Res Ctr, Neuroenter Dis Program,Dept Med, Los Angeles, CA USA
[2] Univ Calif Los Angeles, Sch Med, CURE Digest Dis Res Ctr, Neuroenter Dis Program,Dept Physiol, Los Angeles, CA USA
[3] VA Greater Los Angeles Healthcare Syst, Dept Psychol, Los Angeles, CA USA
[4] Hanyang Univ, Dept Med, Coll Med, Seoul, South Korea
[5] Inst Nacl Ciencias Med & Nutr Salvador Zubiran, Dept Gastroenterol, Mexico City, DF, Mexico