Abnormal forebrain activity in functional bowel disorder patients with chronic pain
Bibliographic record
Abstract
BACKGROUND: Abnormal cortical pain responses in patients with fibromyalgia and conversion disorder raise the possibility of a neurobiologic basis underlying so-called "functional" chronic pain. OBJECTIVE: To use percept-related fMRI to test the hypothesis that patients with a painful functional bowel disorder do not process visceral input or sensations normally or effectively at the cortical level. METHODS: Eleven healthy subjects and nine patients with irritable bowel syndrome (IBS) underwent fMRI during rectal distensions that elicited either a moderate level of urge to defecate or pain. Subjects continuously rated their rectal stimulus-evoked urge or pain sensations during fMRI acquisition. fMRI data were interrogated for activity related to stimulus presence and to specific sensations. RESULTS: In IBS, abnormal responses associated with rectal-evoked sensations were identified in five brain regions. In primary sensory cortex, there were urge-related responses in the IBS but not control group. In the medial thalamus and hippocampus, there were pain-related responses in the IBS but not control group. However, pronounced urge- and pain-related activations were present in the right anterior insula and the right anterior cingulate cortex in the control group but not the IBS group. CONCLUSIONS: Percept-related fMRI revealed abnormal urge- and pain-related forebrain activity during rectal distension in patients with irritable bowel syndrome (IBS). As visceral stimulation evokes pain and triggers unconscious processes related to homeostasis and reflexes, abnormal brain responses in IBS may reflect the sensory symptoms of rectal pain and hypersensitivity, visceromotor dysfunction, and abnormal interoceptive processing.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".