SWITZERLAND – Our heart is constantly beating, and yet we’re not conscious most of the time. In fact, our brain is equipped to filter sensory hubbub of cardiac activity so that it does not interfere with the sensations from outside. A mysterious brain mechanism that has been identified for the first time by researchers from the Ecole Polytechnique Fédérale de Lausanne (EPFL), in their work published in The Journal of Neuroscience.

Our heart influences what we see

To locate the brain region involved, the researchers subjected 150 volunteers to specific visual stimuli – in this case an octagon shape flashing on a screen. When the geometric shape flashes at the volunteer’s heart rate, it has more difficulty to perceive it.  As if the brain was trying to avoid dealing with this information even if they are synchronized with the heart beat. They then repeated the experiment in MRI (magnetic resonance imaging) and noticed that when the stimuli visual are not aligned on the heart rate, a specific area called “insular cortex” is in full swing: the subject perceives clearly flashing shapes. On the contrary, when the stimuli are aligned with the heartbeat, insular cortex activity decreases significantly: the subject is less or not at all aware of flashing shapes. Thus, the insular cortex plays as a filter intercepting the feelings of the heart beat.

“We’re not objective, and we do not see anything that falls in the retina as a video camera,” said Roy Solomon, co-author of the study. The brain decides to be conscious only on certain information. And surprisingly, our heart influences what we see! “A mechanism that could be directly linked to the development of in utero organs.” The brain then forms the heart is already beating. We are therefore exposed to our “internal noise” since the early days of our existence, and it is likely that the brain seeks to reduce, to make it less aware,” added the specialist.

A link with anxiety disorders?

The perception of the heart rate is correlated with certain psychological problems in patients with anxiety disorders tend to perceive their heart more clearly than the normal population, say the authors of the study. Can these problems, at least partially, be the cause or the consequence of a failure to reduce sensations heartbeat? “We do not know yet,” replied Roy Solomon. Maybe this specialist will unveil this mystery in its future work.