The Insula Mediates Access to Awareness of Visual Stimuli Presented Synchronously to the Heartbeat

Roy Salomon (1, 2) , Roberta Ronchi (1, 2) , Jonathan Dönz (1, 2) , Javier Bello-Ruiz (1, 2) , Bruno Herbelin (1, 2) , Remi Martet (1, 2) , Nathan Faivre (3, 1) , Karl Schaller (4) , Olaf Blanke (1, 2)

1 EPFL - Ecole Polytechnique Fédérale de Lausanne
2 LNCO - Laboratory of Cognitive Neuroscience
3 CES - Centre d'économie de la Sorbonne
4 Department of Medical Imaging and Information Sciences, Interventional Neuroradiology Unit

The processing of interoceptive signals in the insular cortex is thought to underlie self-awareness. However, the influence of interoception on visual awareness and the role of the insular cortex in this process remain unclear. Here, we show in a series of experiments that the relative timing of visual stimuli with respect to the heartbeat modulates visual awareness. We used two masking techniques and show that conscious access for visual stimuli synchronous to participants' heartbeat is suppressed compared with the same stimuli presented asynchronously to their heartbeat. Two independent brain imaging experiments using high-resolution fMRI revealed that the insular cortex was sensitive to both visible and invisible cardio–visual stimulation, showing reduced activation for visual stimuli presented synchronously to the heartbeat. Our results show that interoceptive insular processing affects visual awareness, demonstrating the role of the insula in integrating interoceptive and exteroceptive signals and in the processing of conscious signals beyond self-awareness.

Mots clés: continuous flash suppression; high-resolution fMRI; insula; interoception; visual awareness

Domaines: Neurosciences; Psychologie

Roy Salomon, Roberta Ronchi, Jonathan Dönz, Javier Bello-Ruiz, Bruno Herbelin, et al.. The Insula Mediates Access to Awareness of Visual Stimuli Presented Synchronously to the Heartbeat. Journal of Neuroscience, 2016, ⟨10.1523/JNEUROSCI.4262-15.2016⟩. ⟨hal-01312914⟩