Decision-making involves a little known brain region

September 24, 2015, CNRS
Decision-making involves a little known brain region
To visualize the neural pathways, two markers (red and green) were applied to two regions of the orbitofrontal cortex. These compounds then migrated, accumulating in the thalamic neurons. Dense labeling with the two tracers is visible in the submedius thalamic nucleus (delimited by a dotted line). Credit: Bordeaux Imaging Centre/Fabien Alcaraz

When faced with a change to our environment, we have to make appropriate decisions, which usually involves the orbitofrontal cortex. Yet unexpectedly, scientists at the Institut de Neurosciences Cognitives et Intégratives d'Aquitaine (INCIA, CNRS/Université de Bordeaux) have discovered that a brain region located in the thalamus also plays a crucial role in using these evolved skills. Tested in the rat, this work is published on 23 September 2015 in The Journal of Neuroscience.

All living organisms must take appropriate decisions to meet their own needs. In particular, the ability to take account of abrupt environmental changes represents a significant challenge for the survival of a species. Such decision-making is considered as an evolved cognitive function. It involves the , one of the most developed brain structures, known to perform decision-making processes.

The "Décision et Adaptation" team at the INCIA first of all focused on the brain regions connected to the orbitofrontal cortex. Using a labeling technique, the scientists evidenced a specific area, the thalamic submedius nucleus, which is closely linked to the orbitofrontal cortex and whose functional role is unknown.

The team then tested the role of these two brain structures (the submedius thalamic nucleus and orbitofrontal cortex) in decision-making and adaptive behavior. To achieve this, they studied three groups of rats: the first presented lesions to the orbitofrontal cortex, the second had lesions on the submedius nucleus and the third was made up of lesion-free control animals. The objective was to test their ability to establish a link between an auditory cue and obtaining a food reward.

The experiment was organized in two phases. The initial learning phase allowed the animals to learn that two different sounds (S1 and S2) each signaled a specific . The three groups of animals thus visited the food dispenser as soon as an auditory stimulus was perceived. The lesions did not prevent the animals from learning that an auditory stimulus predicts a reward. During the second phase, the procedure remained unchanged for the first cue, but for S2, the scientists distributed food rewards during, and mostly outside, cue test periods. This sound thus lost its predictive value and lesion-free animals started to take no account of the S2 auditory stimulus, only visiting the dispenser when they heard S1. On the other hand, animals with a lesion - of either the orbitofrontal cortex or the submedius thalamic nucleus - proved incapable of making this distinction, and thus of adapting.

This study therefore identified the existence of a circuit between the thalamus and the , which proved crucial to adaptive decision-making. The originality of this discovery lies in the key role that scientists attribute to the submedius thalamic nucleus, a structure hitherto poorly known in the field of . These findings suggest that numerous functional circuits underlying this type of behavior may involve a contribution from the thalamus. The team is now planning to explore these "thalamocortical" circuits, whose understanding could shed light on numerous diseases, such as schizophrenia or addiction.

Explore further: The role of a specific brain region in deciding between conflicting options

More information: "Flexible Use of Predictive Cues beyond the Orbitofrontal Cortex: Role of the Submedius Thalamic Nucleus." Journal of Neuroscience, 23 September 2015, 35(38): 13183-13193; DOI: 10.1523/JNEUROSCI.1237-15.2015

Related Stories

The role of a specific brain region in deciding between conflicting options

November 7, 2014
A type of information processing in the brain known as 'executive control' helps us make decisions when presented with conflicting options. Brain imaging studies of humans have established that specific regions in an area ...

Feeling anxious? Check your orbitofrontal cortex and cultivate your optimism

September 22, 2015
A new study links anxiety, a brain structure called the orbitofrontal cortex, and optimism, finding that healthy adults who have larger OFCs tend to be more optimistic and less anxious.

Waiting for pleasure: Brain structures involved in delayed gratification identified

August 4, 2015
Researchers at McGill have clearly identified, for the first time, the specific parts of the brain involved in decisions that call for delayed gratification. In a paper recently published in the European Journal of Neuroscience, ...

Researchers target two brain sites responsible for anxiety

March 30, 2015
(MedicalXpress)—As distinct from a fear response to a real, immediate threat, anxiety is an expectation of future threat. The symptoms of anxiety disorders and the treatment of those symptoms are largely understood, but ...

Study pinpoints brain area's role in learning

November 26, 2012
An area of the brain called the orbitofrontal cortex is responsible for decisions made on the spur of the moment, but not those made based on prior experience or habit, according to a new basic science study from substance ...

How your brain is telling you to vote

June 8, 2015
A new joint study by researchers at the Montreal Neurological Institute and the Centre for the Study of Democratic Citizenship, both at McGill University, has cast some light on the brain mechanisms that support people's ...

Recommended for you

Paraplegic rats walk again after therapy, now we know why

March 19, 2018
With the help of robot-assisted rehabilitation and electrochemical spinal cord stimulation, rats with clinically relevant spinal cord injuries regained control of their otherwise paralyzed limbs. But how do brain commands ...

Scientists locate nerve cells that enable fruit flies to escape danger

March 19, 2018
Columbia University researchers have identified the nerve cells that initiate a fly's escape response: that complex series of movements in which an animal senses, and quickly maneuvers away from, something harmful such as ...

Decision-making is shaped by individual differences in the functional brain connectome

March 19, 2018
Each day brings with it a host of decisions to be made, and each person approaches those decisions differently. A new study by University of Illinois researchers found that these individual differences are associated with ...

New research into letter-spacing could help improve children's reading

March 19, 2018
Increased letter spacing helps individuals read faster, but not due to visual processing, according to new research from Binghamton University, State University of New York.

Decoding the chemistry of fear

March 19, 2018
Ask a dozen people about their greatest fears, and you'll likely get a dozen different responses. That, along with the complexity of the human brain, makes fear—and its close cousin, anxiety—difficult to study. For this ...

Kids with severe brain injuries may develop ADHD: study

March 19, 2018
(HealthDay)—Young children who sustain a severe head injury may struggle with attention problems as they grow older, researchers say.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Sep 24, 2015
So our lofty notion of "free will" comes down to a small cluster of neurons. I am not surprised one bit.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.