Brain-gut connection

The brain-gut axis describes the communication between the brain and the digestive tract.  The digestive tract contains a large number of nerve cells (more than any other organ except the brain), and for this reason is sometimes referred to as the ‘little brain’. The ‘little brain’ shares many important connections with the ‘big brain’. The normal function of the brain-gut axis is to regulate digestion and the movement of food without conscious awareness. Unfortunately, sometimes the signals become scrambled or misinterpreted, contributing to digestive discomfort.

The brain-gut axis links emotional and cognitive centres of the brain with peripheral functioning of the digestive tract. The digestive tract and the brain develop from closely related parts of the embryo, and as a result they communicate extensively via nerves such as the Vagus nerve, and share similar nerve endings and chemicals that relay signals and messages (neurotransmitters). This is how stress, thought, emotion, and psychological problems can affect gut sensation, feeling, motility, and secretion. Conversely, sensations arising in the gut can affect the central brain, leading to pain or to changes in mood and behaviour.

Normal digestive function is characterised by a high degree of coordination between the gut and brain. However, in patients with digestive problems, there is often a disruption in the brain-gut axis.  This can result in abnormal gut motility and hypersensitivity of the gastrointestinal tract.  Digestive symptoms seem to be related to both abnormal reception or processing of gut signals by the brain, as well as an increased sensitivity in the brain and in the gut.