Like a treasure map, brain region emphasizes reward location

June 01, 2020

We are free to wander but usually when we go somewhere it's for a reason. In a new study, researchers at The Picower Institute for Learning and Memory show that as we pursue life's prizes a region of the brain tracks our location with an especially strong predilection for the location of the reward. This pragmatic bias of the lateral septum suggests it's a linchpin in formulating goal-directed behavior.

"It appears that the lateral septum is, in a sense, 'prioritizing' reward-related spatial information," said Hannah Wirtshafter, lead author of the study in eLife and a former graduate student in the MIT lab of senior author Matthew Wilson, Sherman Fairchild Professor of Neurobiology. Wirtshafter is now a postdoc at Northwestern University.

Last year, Wirtshafter and Wilson, a professor of biology and of brain and cognitive sciences, analyzed measurements of the electrical activity of hundreds of neurons in the LS and the hippocampus, a region known for encoding many forms of memory including spatial maps, as rats navigated a maze toward a reward. In Current Biology they reported that the LS directly encodes information about the speed and acceleration of the rats as they navigated through the environment.

The new study continued this analysis, finding that while the LS dedicates a much smaller proportion of its cells to encoding location than does the hippocampus, a much larger proportion of those cells respond when the rat is proximate to where the reward lies. Moreover, as rats scurried toward the reward point and back again within the H-shaped maze, the pace of their neural activity peaked closest to those reward locations, skewing the curve of their activity in association with where they could find a chocolate treat. Finally, they found that neural activity between the hippocampus and the LS was most highly correlated among cells that represented reward locations.

"Understanding how reward information is linked to memory and space through the hippocampus is crucial for our understanding of how we learn from experience, and this finding points to the role the lateral septum may play in that process," Wilson said.

Specifically, Wilson and Wirtshafter interpret the results of the two studies to suggest that the LS plays a key role in helping to filter and convert raw information about location, speed and acceleration coming in from regions such as the hippocampus, into more reward-specific output for regions known to guide goal-directed behavior, such as the ventral tegmental area. In the paper they discuss ways in which the hippocampus and the LS might be wired together to do so. They theorize that the LS may dedicate neurons to receiving reward-related location information from the hippocampus and may blend non-reward location information within neurons also tasked for processing other information such as motion.

"This is supported by our previous work that shows somewhat overlapping populations of place-encoding and movement-encoding LS cells," Wirtshafter said.

Though it's easy for most of us to take the brain's ability to facilitate navigation for granted, scientists study it for several reasons, Wirtshafter said.

"Elucidating brain mechanisms and circuits involved in navigation, memory and planning may identify processes underlying impaired cognitive function in motor and memory diseases," she said. "Additionally, knowledge of the principles of goal directed behavior can also be used to model context-dependent brain behavior in machine models to further contribute to artificial intelligence development."
-end-
The National Defense Science & Engineering Graduate Fellowship Program and the JPB Foundation provided funding for the study.

Picower Institute at MIT

Related Neurons Articles from Brightsurf:

Paying attention to the neurons behind our alertness
The neurons of layer 6 - the deepest layer of the cortex - were examined by researchers from the Okinawa Institute of Science and Technology Graduate University to uncover how they react to sensory stimulation in different behavioral states.

Trying to listen to the signal from neurons
Toyohashi University of Technology has developed a coaxial cable-inspired needle-electrode.

A mechanical way to stimulate neurons
Magnetic nanodiscs can be activated by an external magnetic field, providing a research tool for studying neural responses.

Extraordinary regeneration of neurons in zebrafish
Biologists from the University of Bayreuth have discovered a uniquely rapid form of regeneration in injured neurons and their function in the central nervous system of zebrafish.

Dopamine neurons mull over your options
Researchers at the University of Tsukuba have found that dopamine neurons in the brain can represent the decision-making process when making economic choices.

Neurons thrive even when malnourished
When animal, insect or human embryos grow in a malnourished environment, their developing nervous systems get first pick of any available nutrients so that new neurons can be made.

The first 3D map of the heart's neurons
An interdisciplinary research team establishes a new technological pipeline to build a 3D map of the neurons in the heart, revealing foundational insight into their role in heart attacks and other cardiac conditions.

Mapping the neurons of the rat heart in 3D
A team of researchers has developed a virtual 3D heart, digitally showcasing the heart's unique network of neurons for the first time.

How to put neurons into cages
Football-shaped microscale cages have been created using special laser technologies.

A molecule that directs neurons
A research team coordinated by the University of Trento studied a mass of brain cells, the habenula, linked to disorders like autism, schizophrenia and depression.

Read More: Neurons News and Neurons Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.