MRI brain scanner distorts perception of space

Functional magnetic resonance imaging (fMRI) can be used to make the working brain visible. Now brain researchers from Tübingen have discoveredThat the magnetic field generated during the process itself affects the performance of our brain and distorts spatial awareness.

An MRI machine generates a very strong magnetic field, the strength of which is specified in Tesla. As a rule, tomographs from 1.5 to 7 Tesla are used. For comparison: the magnetic field of a 7-tesla device is about 140,000 times stronger than Earth’s magnetic field. Nevertheless, an MRI scan is safe and not harmful to the body. However, some people feel a bit dizzy when they lie down in the tube or get out of it too quickly. However, the fact that this process has a fundamental effect on perception is new.

It was already known from previous studies that the MRI field has an effect on the organ of balance in the inner ear.. The effect is similar to what happens when the head naturally moves to the left or right. In this case, a vestibulo-ocular reflex occurs: the eye tries to stabilize the image on the retina, opposing the gaze so as to keep an object still. This effect can also affect the fMRI signal in areas of the cortex, In 2016 showed Marianne Dietrich from Ludwig Maximilians University in Munich.

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The research team, led by neurologist Hans-Otto Karnnath of the Herty Institute for Clinical Brain Research in Tübingen, now turned to the question of whether subjects’ spatial perception also changed during MRI scans.