I suggest the following recent papers: Elsenbruch S et al, Gastroenterology 2010; 139:1310-9 and Tillisch K, Gastroenterology 2011; 140(2):407-411. Perhaps, they may help to answer your question
Thank you for the suggestions. I check mentioned papers and try to find appropriate explanation for the relationship between anxiety and attention processes in IBS patients.
IBS and other FBD have a phenimenon called vigilance arousal in CNS which cause even minor somatic and visceral afferent sensations to be perceived as danger and hence the anxiety. This is absent in a normal person. It is mainly due to the predisposition of a weak psyche to record all stimuli as noxious and this may be set due to family tension, childhood trauma or infections etc.