On Monday, the Zanvyl Krieger Mind/Brain Institute invited Dr. Richard Krauzlis to speak about his new research findings.
Faculty members, postdoctoral students and graduate students can invite speakers to talk at this speaker series, which the Institute has been hosting for about 10 years. People often choose speakers because they have similar research interests.
Dr. Manuel Gomez-Ramirez, who is studying mechanisms of selective attention in the brain, selected Krauzlis to come speak.
“I do know his work, which is very related to mine,” Gomez-Ramirez said.
The seminars often bring members of the psychology and neuroscience departments and the medical school together. The Mind/Brain Institute conference room was at maximum capacity with about 50 people in attendance for the lecture entitled “A New Framework for Thinking about Attention.” He emphasized that human attention is selective.
To elucidate his message, Krauzlis displayed two nearly identical photographs and flipped between the two so that people might spot the difference. While looking at the entire picture, about 10 percent of people pinpointed the difference. However, when told which specific area of the photograph they had to analyze, the entire room spotted the change in the photograph.
Krauzlis’s research largely focused on the superior colliculus, a structure on the roof of the midbrain. The superior colliculus is the region that perceives and translates vision.
“[The lecture was] broadly about attention and how you’re going to attend to specific locations,” Doug Goodsmith, a second-year graduate student in Psychological and Brain Sciences, said.
Rita Liotile, a third-year graduate student in Psychological and Brain Sciences, also summarized the significance of Krauzlis’s findings.
“The idea has been that attention acts as a modulator,” she said. “So [the brain] sort of attenuates the signal of things you’re not paying attention to and increases the signal of things you are paying attention to.”
Krauzlis found that stimulants in the brain were not necessarily reflected in certain reactions.
“You’re getting an amplified signal of what you’re attending to relative to everything else in the world,” Krauzlis said.
“The idea is that even though you can have an amplified perceptual signal of, in this case, vision... it may not trickle down into your behavioral choices, which was sort of the cool finding,” Lioitile said. “Instead, there is another amplification necessary from another structure, in this case the superior colliculus, that need not interact with that previous sensory amplification.”
An experiment using an injectrode that placed chemicals into the superior colliculus found that monkeys were trained to respond to changes they saw in a visual pattern. The monkeys acknowledge changes by an eye saccade, a quick shift of the eyes, and then by pressing a button. While the neurons demonstrated similar activity with the chemical stimulant as without it, the monkeys behaved differently without the stimulant.
“The superior colliculus affected how the monkey responded and what it looked like he was able to discriminate, even though he was actually getting the relevant signals in perfectly modulated form,” Lioitile said.
Part of what makes this experiment significant is the anomaly it presents.
“The thing that everyone always thinks is that as long as the signal is attenuated, you base your choices, and you can get information from this modulated signal where there is an amplifier on the things you are paying attention to, and there is sort of a turn down volume on the things that you are not paying attention to,” Lioitile said. “It turns out that even when this loudspeaker of the thing you are supposed to be paying attention to was actually happening in the visual cortex, the monkey doesn’t behave like [that].”
Krauzlis’s research did not affect past findings, but it did demonstrate that just because something is being modulated in a perceptual area of the brain does not necessarily indicate a certain behavior.
Gomez-Ramirez’s and Krauzlis’s research are similar in that they both analyze attention. However, Gomez-Ramirez focuses his research on attention related to hands, whereas Krauzlis researches visual attention. The two study different parts of the brain and conduct tests on subjects in order to reach conclusions.
“We typically record activity while a subject is doing a task... for example, holding a cup or processing the texture of an object,” Gomez-Ramirez said.
Krauzlis is well-known in his field for his research. He received an undergraduate degree from Princeton University and a Ph.D. in neuroscience from the University of California, San Francisco. After completing his postdoctoral training, he was recruited by the Salk Institute.
“Exploring the molecular basis of diseases makes curing them more likely,” the Institute’s mission statement reads. “In an outstanding and unique environment we gather the foremost scientific minds in the world and give them the freedom to work collaboratively and think creatively.”
Krauzlis now works at the National Eye Institute, a division of the National Institute of Health in Bethesda, Md.
“He is very well-accomplished,” Gomez-Ramirez said. “Typically, the seminar speakers are very well-known in the field that attract general audiences.”
