It was hypothesized that symptoms in functional dyspepsia are originated by an altered mechanism at the brain-gut axis (one or several) in the process of gastric accommodation to a meal. To test the key mechanisms potentially involved in symptomatic gastric accommodation, the sensorial responses (on a 0-10 perception score) and the gastric tone responses (by electronic barostat) to either gastric accommodation (n = 10) or to cold stress (n = 10) were measured in 20 patients with functional dyspepsia and 20 healthy controls. The mechanical accommodation of the stomach to gastric distention (compliance) was similar in patients (52 ± 8 mL/mm Hg) and controls (57 ± 6 mL/mm Hg). However, isobaric gastric distention elicited more upper abdominal discomfort in dyspeptics than in controls (perception scores, 4.7 ± 0.9 vs. 1.1 ± 0.5, respectively; mean ± SE; P < 0.005). Cold stress induced a similar gastric relaxatory response in dyspeptics and controls (Δ vol, 145 mL ± 40 mL vs. 141 mL ± 42 mL, respectively); hand perception (scores, 8.3 ± 0.4 vs. 7.9 ± 0.4, respectively) and autonomic responses were also similar. It is concluded that an abnormal afferent sensorial pathway (altered gastric perception) may be a major mechanism of symptom production in functional dyspepsia. © 1991.