[ Source: The Picower Institute | April 21, 2022 ]
In a new brain-wide circuit tracing study, scientists at MIT’s Picower Institute for Learning and Memory focused selective attention on a circuit that governs, fittingly enough, selective attention. The comprehensive maps they produced illustrate how broadly the mammalian brain incorporates and integrates information to focus its sensory resources on its goals.
Working in mice, the team traced thousands of inputs into the circuit, a communication loop between the anterior cingulate cortex (ACC) and the lateral posterior (LP) thalamus. In primates the LP is called the pulvinar. Studies in humans and non-human primates have indicated that the byplay of these two regions is critical for brain functions like being able to focus on an object of interest in a crowded scene, said study co-lead author Yi Ning Leow, a graduate student in the lab of senior author Mriganka Sur, Newton Professor in MIT’s Department of Brain and Cognitive Sciences. Research has implicated dysfunction in the circuit in attention-affecting disorders such as autism and ADHD.
The new study in the Journal of Comparative Neurology extends what’s known about the circuit by detailing it in mice, Leow said, importantly showing that the mouse circuit is closely analogous to the primate version even if the LP is proportionately smaller and less evolved than the pulvinar.
“In these rodent models we were able to find very similar circuits,” Leow said. “So we can possibly study these higher order functions in mice as well. We have a lot more genetic tools in mice so we are better able to look at this circuit.”
The study, also co-led by former MIT undergraduate Blake Zhou, therefore provides a detailed roadmap in the experimentally accessible mouse model for understanding how the ACC and LP cooperate to produce selective attention. For instance, now that Leow and Zhou have located all the inputs that are wired into the circuit, Leow is tapping into those feeds to eavesdrop on the information they are carrying. Meanwhile, she is correlating that information flow with behavior.
“This study lays the groundwork for understanding one of the most important, yet most elusive, components of brain function, namely our ability to selectively attend to one thing out of several, as well as switch attention,” Sur said.