Vision involves hearing too, claims researchers

Researchers studying brain process involved in sight have discovered that the visual cortex also uses information gleaned from the ears as well as the eyes when viewing the world.

Professor Lars Muckli, of the Institute of Neuroscience and Psychology at the University of Glasgow, who led the research, said that sounds create visual imagery, mental images, and automatic projections.

The study involved conducting five different experiments using functional Magnetic Resonance Imaging (fMRI) to examine the activity in the early visual cortex in 10 volunteer subjects.

In one experiment they asked the blindfolded volunteers to listen to three different natural sounds - birdsong, traffic noise and a talking crowd.

Using a special algorithm that can identify unique patterns in brain activity, the researchers were able to discriminate between the different sounds being processed in early visual cortex activity.

A second experiment revealed even imagined images, in the absence of both sight and sound, evoked activity in the early visual cortex.

Muckli said this research enhances their basic understanding of how interconnected different regions of the brain are.

The study has been published in the journal Current Biology.