How brain controls attention span

Like a spotlight that illuminates an otherwise dark scene, attention highlights specific details of our surroundings while shutting others out.

A new study by Salk Institute for Biological Studies researchers shows that the superior colliculus, a brain structure known for its role in the control of eye and head movements, is crucial for moving the mind’s spotlight.

Their findings add new insight to our understanding of how attention is controlled by the brain.

The results are closely related to a neurological disorder known as the neglect syndrome, and they may also shed light on chronic attention problems, such as autism or attention deficit disorder.

“Our ability to survive in the world depends critically on our ability to respond to relevant pieces of information and ignore others,” explains graduate student Lee Lovejoy, who co-authored the study with Richard Krauzlis, associate professor, Salk’s Systems Neurobiology Lab.

It had been known that the superior colliculus plays a role in deciding how to orient the eyes and head to interesting objects in the environment. But it was not clear whether it also had a say in covert attention.

In their current study, the Salk researchers specifically asked whether the superior colliculus is necessary for covert attention.

To tease out the superior colliculus’ role in covert attention, they designed a motion discrimination task that distinguished between control of gaze and control of attention.

The superior colliculus contains a topographic map of the visual space around us, just as conventional maps mirror geographical areas.

“The result is very similar to what happens in patients with neglect syndrome,” explains Lovejoy, who is also a student in the Medical Scientist Training Program at University of California-San Diego (UCSD).

“Up to a half of acute right-hemisphere stroke patients demonstrate signs of spatial neglect, failing to be aware of objects or people to their left in extra-personal space.”

The findings were published in the December issue of Nature Neuroscience.