I asked the experts at the UNC a while back about this as some know and technically they are not spasms but contractions.Flux, I still need to ask them about the other question, which I will do soon.A couple things, one is how the bowel actually works, it has to distend like a ballon you feel with air in order to feel anything, because it doesn't release neurotransmitters until that happens.But"Pain and BloatingNormal, Relaxed Bowel Bowel With IrregularContractions The well-functioning bowel has regular, rhythmic contractions, which in IBS, become disrupted. Depending on the strength of bowel contractions and the amount of intestinal gas, painful abdominal cramps may be experienced. Variations in intestinal contractions, which may cause material in one section of the intestine to be passing slowly while material in another section is passing quickly, and when these actions occur simultaneously, painful cramps result as well as the characteristic alternating between constipation and diarrhea. Also, prolonged contractions of the bowel may prevent the normal passage of air through the bowel, triggering bloating, belching, and flatulence. Bloating can become so severe that clothing needs to be adjusted and abdominal swelling becomes visible to others.Pain is varied among individuals with IBS. It may be ongoing or it may resolve very quickly. It can occur occasionally or frequently, and it can move around from one location in the bowel to another. Digestive pain often occurs following a meal and can last for hours."
http://www.badgut.com/index.php?contentFil...+Bowel+Syndrome
You might want to read this alsoVisceral Sensations and Brain-Gut MechanismsBy: Emeran A. Mayer, M.D., Professor of Medicine, Physiology and Psychiatry; Director, Center for Neurovisceral Sciences & Women's Health, David Geffen School of Medicine at UCLAThe most common symptoms of IBS patients are related to altered perception of sensations arising from the GI tract, and frequently from sites outside the GI tract, such as the genitourinary system or the musculoskeletal system. Sensations of bloating, fullness, gas, incomplete rectal evacuation and crampy abdominal pain are the most common symptoms patients experience. Numerous reports have demonstrated that a significant percentage of FBD patients (about 60%) rate experimental distensions of the colon as uncomfortable at lower distension volumes or pressures when compared to healthy control subjects. This finding of an increased perception of visceral signals ("visceral hypersensitivity") has been demonstrated during balloon distension tests of the respective part of the GI tract regardless of where their primary symptoms are â€" the esophagus, the stomach, or the lower abdomen. In contrast to the current emphasis on mechanisms that may result in sensitization of visceral afferent pathways in the gut, it may well be that alterations in the way the nervous system normally suppresses the perception of the great majority of sensory activity arising from our viscera are essential for the typical symptom constellation of IBS and other functional GI disorders to develop.What is unique about perception of visceral events in the GI tract?There are several features which are unique to the perception of sensory stimuli arising from the gastrointestinal tract and which differ from those coming from the rest of the body. These differences may explain many of the symptom characteristics present in FBD patients.Even though the events within the GI tract such as the composition of food, the concentration of acid, or the strength of contractions are continuously monitored by sensory nerve fibers, only a small fraction of this sensory information ever reaches consciousness. The majority of sensory signals play a role in reflex regulation of the digestive process and presumably in the very basic regulation of states like hunger or well being. The only sensory signals which are consciously perceived are those which result in a beneficial behavioral response, such as: the sensation of being "full" following a big meal so that we stop eating, the sensation of rectal fullness and urgency preceding a bowel movement, and the sensation of gas which will result in an attempt to expel the gas from the upper or lower GI tract.
http://www.aboutibs.org/Publications/VisceralSensations.htmlIt has been known now for a while that the "gate" for sensory information arising from the gut to the brain is lost in IBS, so all sensory information gets through.This is also a newer study about it. Study shows link between IBS and pain"Thus, people with IBS have a lower pain threshold because their pain filters appear to malfunction, amplifying rather than dampening the nervous input from the gut to the brain - resulting in a propensity for both abdominal pain, and an increased sensitivity to somatic (skin or surface) pain. "Compared to healthy subjects, IBS patients tend to have a more sensitive bowel. This can be explained by the finding that IBS sufferers have a lower pain threshold for perceiving abdominal pain, when compared to individuals who don't have IBS. "So, IBS patients may feel pain even when the intensity of a stimulation they receive is within a normal range," explained Prof Ho. "
http://www.channelnewsasia.com/stories/hea.../239806/1/.htmlThere have been a lot of studies related to this discussion. Some of them are fmri studies and pet scans studies of the brain and IBS. The brain scans are different then normal controls as well as IBD conditions.There maybe a problem and they are looking into this for quite some time now for the brains anterior cinculate cortex to signal the release of endorphines back down to the gut for pain. However that is just one part of it all.You can get pain from normal gut functioning however in IBS. Not only that but the signal arising from the gut may activate the prefrontal cortex, which is associated with anxiety, as opposed to the ACC which is associated with pain and emotions.