Figure 2.

Brain networks involved in centrai processing and modulation of visceral pain. Shown are the default mode network (DMN) and four task-related brain networks that have been described in the literature, for which structural and functional alterations and correlations with clinical and behavioural measures have been reported in IBS subjects. Correlations of the listed clinical and behavioural measures have been reported for the salience network,^{43,50,65,145,146} sensorimotor network,^46,100,147 emotional arousal network,^{40,45,47,145,147} central executive network,⁴³ central autonomic network^43,45,47 and DMN.¹⁴⁶ Arrows indicate: (A) shift of activity from the DMN to the task-related networks in response to input from the salience network; (B) switching between DMN and central executive network depending on input from the salience network; (C) engagement of emotional arousal network in response to central executive network activation; (D) engagement of central autonomic network in response to emotional arousal network activation; (E) central autonomic network activation with output in the form of descending pain modulation and autonomic nervous system activity to GI tract; (F) ascending viscerosensory signals from gut to sensorimotor network; and (G) assessment of information from sensorimotor network by salience network. The functions of these networks are described in detail in the text. Modified with permission from Mayer et al.⁹