Neuroscientists at New York University said we make our eye movements earlier or later in order to coordinate with movements of our arms, a process coordinated by our brains.
Such coordination is central to the way different systems of the brain communicate with each other, they said, and is surprisingly complicated -- due to differences in weight, for example, the arm takes longer to move than the eye does.
The NYU researchers analyzed the neurological activity of macaque monkeys during a variety of tasks that required them to either reach for something while simultaneously employing rapid eye movements or to only use rapid eye movements.
The analysis revealed significant patterns of firing of neurons in the brain's posterior parietal cortex when both the eyes and arms were required to move for the same task, but not for tasks that involved only eye movement, researches found.
The patterns of firing were found in regions of cortex specialized for moving either the eye or the arm, they said.
"We think we have a mechanism for coordination," neuroscience professor Bijan Pesaran said in an NYU release. "The brain adjusts timing of eye movements, depending on how long it takes to start moving the arm."
The findings give clues to neurological processes that may help rehabilitation for those who have suffered brain injuries and struggle to coordinate movements among different parts of the body, the researchers said.