Circuit that focuses attention brings in wide array of inputs

Date:
April 21, 2022
Source:
Picower Institute at MIT
Summary:
With a comprehensive map of the wiring, researchers can now
discern what information flows into the circuit to enable a key
brain function.



FULL STORY ==========================================================================
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.



========================================================================== Broad input for a focused result Using virally mediated circuit tracing techniques pioneered by co-author Ian Wickersham, Principal Research
Scientist of Brain and Cognitive Sciences at MIT, the team found
distinct sources of input for the ACC and the LP. Generally speaking,
the detailed study finds that the majority of inputs to the ACC were
from frontal cortex areas that typically govern goal-directed planning
and from higher visual areas. The bulk of inputs to the LP, meanwhile,
were from deeper regions capable of providing context such as the
mouse's needs, location and spatial cues, information about movement,
and general information from a mix of senses.

So even though focusing attention might seem like a matter of controlling
the senses, Leow said, the circuit pulls in a lot of other information
as well.

"We're seeing that it's not just sensory -- there are so many inputs
that are coming from non-sensory areas as well, both sub-cortically and cortically," she said. "It seems to be integrating a lot of different
aspects that might relate to the behavioral state of the animal at a
given time. It provides a way to provide a lot of internal and special
context for that sensory information." Given the distinct sets of
inputs to each region, the ACC may be tasked with focusing attention
on a desired object, while the LP is modulating how the ACC goes about
making those computations, accounting for what's going on both inside
and outside the animal. Decoding just what that incoming contextual
information is and what the LP tells the ACC, are the key next steps,
Leow said. Another clear set of questions the study raises are what are
the circuit's outputs. In other words, after it integrates all this
information what does it do with it? The paper's other authors are
Heather Sullivan and Alexandria Barlowe.

A National Science Scholarship, the National Institutes of Health,
and the JPB Foundation provided support for the study.


========================================================================== Story Source: Materials provided by Picower_Institute_at_MIT. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Yi Ning Leow, Blake Zhou, Heather A. Sullivan, Alexandria
R. Barlowe, Ian
R. Wickersham, Mriganka Sur. Brain‐wide mapping of inputs
to the mouse lateral posterior (LP/Pulvinar) thalamus-anterior
cingulate cortex network. Journal of Comparative Neurology, 2022;
DOI: 10.1002/cne.25317 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220421130938.htm

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