It’s the first time neuroscientists have been able to look at the behavior of synaptic circuits at such a fine-grained level of resolution while measuring the effects of attention, said Professor Ron Mangun, dean of social sciences at UC Davis and a researcher at the UC Davis Center for Mind and Brain.
Our brains recreate an internal map of the world we see through our eyes, mapping our visual field onto specific brain cells. Humans and our primate relatives have the ability to pay attention to objects in the visual scene without looking at them directly, Mangun said.
“Essentially, we ‘see out of the corner of our eyes,’ as the old saying goes. This ability helps us detect threats, and react quickly to avoid them, as when a car running a red light at high speed is approach from our side,” he said.
Postdoctoral scholar Farran Briggs worked with Mangun and Professor Martin Usrey at the UC Davis Center for Neuroscience to measure signaling through single nerve connections, or synapses, in monkeys while they performed a standard cognitive test for attention: pressing a joystick in response to seeing a stimulus appear in their field of view.
By taking measurements on each side of a synapse leading into the cerebral cortex, the team could measure when neurons were firing, the strength of the signal and the signal-to-noise ratio.
The researchers found that when the animals were paying attention to an area within their field of view, the signal strength through corresponding synapses leading into the cortex became more effective, and the signal was boosted relative to background noise.
Combining established cognitive psychology with advanced neuroscience, the technique opens up new possibilities for research.
“There are a lot of questions about attention that we can now investigate, such as which brain mechanisms are disordered in diseases that affect attention,” Usrey said.
The method could be used, for example, to probe the cholinergic nervous system, which is impacted by Alzheimer’s disease. It could also help to better understand developmental disorders that involve defects in attention, such as attention deficit hyperactivity disorder and autism.
“It’s going to turn out to be important for understanding and treating all kinds of diseases,” Mangun predicted.
Mangun noted that this work is an example of the effectiveness of interdisciplinary collaboration to tackle tough problems. The researchers from the UC Davis Center for Mind and Brain, which studies cognitive brain mechanisms, and Center for Neuroscience, which studies molecular, cellular and system-level brain mechanisms, each brought specific expertise to the collaborative study.
The work was funded by grants from the National Science Foundation and the National Institutes of Health. Briggs is now an assistant professor at the Geisel School of Medicine at Dartmouth College.
About UC Davis
For more than 100 years, UC Davis has engaged in teaching, research and public service that matter to California and transform the world. Located close to the state capital, UC Davis has more than 33,000 students, more than 2,500 faculty and more than 21,000 staff, an annual research budget of nearly $750 million, a comprehensive health system and 13 specialized research centers. The university offers interdisciplinary graduate study and more than 100 undergraduate majors in four colleges — Agricultural and Environmental Sciences, Biological Sciences, Engineering, and Letters and Science. It also houses six professional schools — Education, Law, Management, Medicine, Veterinary Medicine and the Betty Irene Moore School of Nursing.
- Martin Usrey, Center for Neuroscience, (530) 754-5468, [email protected]
- Ron Mangun, Center for Mind and Brain, (530) 297-4655, [email protected]
- Andy Fell, UC Davis News Service, (530) 752-4533, [email protected]