A brain area we share with fish and reptiles is involved not only in eye movements, but also in transmitting information to the visual cortex. This finding has helped researchers to understand better how our brain interprets images and turns this into actions. The results of the study have been published in Nature Communications.
It had been thought that a specific brain area, the superior colliculus, was only involved in the control of eye movements, but with this study scientists Mehran Ahmadlou and Alexander Heimel of the Netherlands Institute of Neuroscience and some colleagues from the University of Washington show that the colliculus itself transmits the processed information to the visual cortex.
The eye is connected to various brain areas. Most of these connections run via the centre of the brain to the visual cortex at the back of the brain, where the image of the retina is converted into what can be seen where. There are also connections from the eye to the superior colliculus. In humans this is an important area for making eye movements. The colliculus receives messages from the cortex about places that are worth directing the eyes at. It also uses the direct information from the eye to determine where the gaze should be directed.
Reinforcing the processing
When the researchers very briefly disabled the colliculus in mice, by means of light and genetic techniques, the activity in the visual cortex also diminished. The colliculus can thus use this to reinforce the processing of interesting spots in the image in the visual cortex so that they can be analysed more quickly and more accurately.
This finding contributes to an understanding of the workings of the eyes and the brain.