Date:
March 3, 2015
Source:
Carnegie Mellon University
Summary:
Neuroscientists have identified a new pathway by which several brain areas communicate within the brain's striatum. The findings illustrate structural and functional connections that allow the brain to use reinforcement learning to make spatial decisions. Knowing how these specific pathways work together provides crucial insight into how learning occurs. It also could lead to improved treatments for Parkinson's disease.
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Using diffusion spectrum imaging and fiber technology, Carnegie Mellon University neuroscientists have identified a new way that several brain areas communicate in the striatum. The findings illustrate structural and functional connections that allow the brain to use reinforcement learning to make spatial decisions. This discovery will impact learning and could lead to improved treatments for Parkinson's disease.
Credit: Carnegie Mellon University
Published in the Journal of Neuroscience,
the findings illustrate structural and functional connections that allow the
brain to use reinforcement learning to make spatial decisions, such as the
dorsolateral prefrontal (DLPFC), orbitofrontal cortex (OFC) and posterior
parietal cortex (PPC). Communication between these regions is important for
abilities like how a baseball player is able to estimate where to swing his bat
or how a person finds a car in a large parking lot filled with similar cars.
Knowing how these specific pathways work
together provides crucial insight into how learning occurs. It also could lead
to improved treatments for Parkinson's disease.
"By understanding precisely how these
systems communicate together, we can come up with a better understanding for
how these systems operate in the healthy brain, but also start to understand
how in Parkinson's disease different types of systems 'cascade,' or start with
one symptom like motor dysfunction and move to another like memory or
decision-making problems," said Timothy Verstynen, assistant professor of
psychology and a faculty member in the Center for the Neural Basis of Cognition
(CNBC) in CMU's Dietrich College of Humanities and Social Sciences.
The hope is that more knowledge of how the
connectivity is related to behavior will help scientists develop therapeutic
interventions that focus on strengthening potentially weakened or damaged
pathways.
For the study, Verstynen and Kevin Jarbo, a
Ph.D. student in psychology, used diffusion spectrum imaging and fiber
technology to analyze brain images collected from 60 healthy adults. The
advanced imaging techniques allowed Verstynen and Jarbo to visualize the white
matter pathways from the DLPFC, OFC and PPC.
They found that the pathways from all three
areas projected to similar areas within a forebrain region called striatum, a
part of the basal ganglia pathways that are most commonly associated with
Parkinson's disease. The patterns were consistent across all participants.
The researchers followed the structural
connectivity analysis with a functional connectivity analysis by using resting
state fMRI images. The results showed that the convergence zones were not only
structurally connected but functionally connected as well. More importantly,
the areas at the surface of the brain in all three cortical areas showed a high
overlap of structure and functional connectivity.
"Our findings suggest that there may be a
structural and functional network in the brain that allows us to integrate
information about where we are focusing our attention in our visuospatial
environment with reward and punishment signals associated with our past action
choices in order to learn how to update, and hopefully improve, our future
action decisions," Jarbo said.
An additional implication for this study is a
deeper understanding of how reinforcement learning occurs.
"A lot of models of the reinforcement
learning process assume that reward signals from the orbitofrontal cortex
converge with information from other areas. These have been shown to be true
for other regions of the prefrontal cortex. We are the first to show that
spatial attention information from the parietal cortex may also contribute to
this process," Verstynen said.
As the birthplace of artificial intelligence
and cognitive psychology, Carnegie Mellon has been a leader in the study of
brain and behavior for more than 50 years. The university has created some of
the first cognitive tutors, helped to develop the Jeopardy-winning Watson,
founded a groundbreaking doctoral program in neural computation, and completed
cutting-edge work in understanding the genetics of autism. Building on its
strengths in biology, computer science, psychology, statistics and engineering,
CMU recently launched BrainHubSM, a global initiative that focuses
on how the structure and activity of the brain give rise to complex behaviors.
Story Source:
The above story is based on materials provided
by Carnegie Mellon University. Note:
Materials may be edited for content and length.
Cite This Page:
Carnegie Mellon University.
"Neuroscientists identify new way several brain areas communicate."
ScienceDaily. ScienceDaily, 3 March 2015.
<www.sciencedaily.com/releases/2015/03/150303183401.htm>.
http://www.sciencedaily.com/releases/2015/03/150303183401.htm
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