Washington, February 15 : German researchers have come up with an explanation for why the world appears stable even when people move their eyes.
The research team from the University of Munster says that humans move their eyes two to three times a second without noticing, and each gaze shift triggers a host of internal brain processes.
Just before a gaze shift, the brain shifts attention towards the new gaze target for a very brief period, say the researchers. This improves visual processing at the target area about 50 milliseconds before the eye itself looks at the target, they add.
According to the researchers, the preceding improvement increases the sensitivity of visual neurons in many brain areas, which then respond more strongly to stimuli near the gaze target just prior to the gaze movement.
To investigate the consequences of these sensitivity changes to the perception of spatial location, the researchers used a detailed neuro-computational model of the representation of the visual world in cortical maps.
They observed that the brain dynamically recruits cells for processing visual information around the target, which enables one to perceive details of the object before looking at it. This is why the world always appears to be stable, say the researchers.
The research team believes that its model paves the way to develop novel concepts for artificial vision systems.
The study has been published in the open-access journal PLoS Computational Biology.