Thesis defense

Influence of the electrical rhythm of the stomach in the functional organization of the resting brain

Ignacio Rebollo
Practical information
16 October 2019

ENS, room Dussane, 45 rue d'Ulm, 75005 Paris


- Céline Amiez, Université de Lyon 1, (rapporteur)
- Daniel Margulies,  Institut du Cerveau et de la Moëlle Epinière (rapporteur)
- Nathalie George, Institut du Cerveau et de la Moëlle Epinière (examinateur)
- Karim Benchenane, ESPCI Paris (membre invite du Jury)
- Catherine Tallon-Baudry, Ecole Normale Supérieure (directrice de thèse)

This thesis endeavors to determine in humans the impact of visceral inputs on brain activity, a field that has received surprisingly little attention despite the heavy connections between the brain and viscera. More precisely, during my PhD I studied the influence of the gastric rhythm on spontaneous brain dynamics measured by functional magnetic resonance imaging. In the first part of my PhD, I found an extended network of cortical regions synchronized to the slow electric rhythm continuously produced by the stomach. This gastric network is characterized by a precise temporal sequence of activations within each cycle of the stomach, and is composed of regions with convergent functional properties involved in mapping bodily space through touch, action or vision, as well as mapping external space in bodily coordinates. In the second part of My PhD, I extended these findings by using a larger sample and further characterized the anatomy, effect sizes and inter-individual variability of the gastric network. The gastric network is mostly confined to motor, somatosensory, insular, visual and auditory and, to a lesser extent, in the piriform cortex, indicating that all sensory-motor cortices corresponding to both exteroceptive and interoceptive modalities are coupled to the gastric rhythm during rest. These results indicate that two major functions of the brain which are usually studied separately – i.e. interaction with the external environment and interaction with the viscera -, are in fact probably tightly intertwined, and that gastric monitoring and sensory-motor processes are likely to interact.