A systematic review of associations between functional connectivity, mood and cognition in patients with irritable bowel syndrome

Irritable bowel syndrome (IBS) affects 9.3%–35.5% of the population, with women at greater risk. It is often comorbid with anxiety, depression, and cognitive dysfunction. Understanding the neural mechanisms underlying these comorbidities is crucial for identifying IBS pathology and developing targeted treatments. Functional magnetic resonance imaging (fMRI) offers valuable insights into brain connectivity and psychopathology. This review evaluates research on the link between functional connectivity, mood, and cognition in IBS. We systematically searched Embase, PubMed, and PsycINFO for studies published between 2010 and 2024, identifying 49 studies using both resting-state and task-based fMRI. Of these, 12 studies meeting inclusion criteria were reviewed. Across studies, IBS was associated with altered connectivity in the salience (SN), sensorimotor (SMN), default mode (DMN), and executive control (ECN) networks. Reported cognitive findings largely reflected executive and attentional control processes occurring in the context of pain anticipation, salience detection, and interoceptive awareness rather than domain-general cognitive impairment. Alterations in the SN, particularly involving the pregenual anterior cingulate cortex and anterior midcingulate cortex, were linked to increased visceral sensitivity and affective symptoms. Disrupted DMN connectivity was associated with altered self-referential processing and emotional regulation, while changes in the SMN and ECN suggested differences in sensory integration and top-down control. Notably, several studies showed that group differences in functional connectivity were reduced or no longer significant after accounting for anxiety and depression, suggesting that mood symptoms may play a mediating role in brain network alterations in IBS. While the literature is limited by small samples and sex imbalance, this review highlights a multi-network model of IBS that emphasizes emotional–cognitive–visceral interactions and points to important directions for future longitudinal research. This review examines both task-based and resting-state fMRI studies in IBS, focusing on brain alterations linked to mood and cognition. Anxiety and depression are associated with abnormal activation in the cingulate cortex, insula, prefrontal cortex, and cerebellum during pain and non-painful visceral stimulation. IBS patients show altered activity in the Executive Control Network (ECN) and Salience Network (SN) during cognitive tasks, including set-shifting and attention switching. Resting-state fMRI reveals disrupted functional connectivity within and between the Default Mode Network (DMN), SN, and ECN in relation to mood symptoms. IBS-related connectivity differences are often diminished after accounting for anxiety and depression, indicating that mood symptoms contribute meaningfully to observed network alterations.