Basal ganglia change neuronal codes for learned skills versus innate

ABSTRACT: A new study reveals that the basal ganglia of the brain use two different neural “languages” to control movement, one for skills learned and another for innate behaviors. When studying rats, researchers discovered that the dorsolateral striatum was essential for tasks learned, but not for natural movements such as walking or preparing.

Neuronal recordings showed completely different electrical activity patterns depending on the type of movement, suggesting that basal ganglia can change between active control and passive observation. These findings can offer a new vision of disorders such as Parkinson’s, where the defective signals of basal ganglia interrupt motor control.

Key facts

Dual coding: Basal nodes use different neuronal codes for the movements learned versus innate. Essential for learning: damage to dorsolateral striatum deteriorates learned skills, but causes natural behaviors.

Source: Harvard

Among the many wonders of the brain is its ability to master the movements learned: a dance step, piano sonata or tie our shoes, acquired through the test and error practice.

For decades, neuroscientists have known that these tasks require a group of brain areas known as basal ganglia.

According to a new study led by Harvard researchers in nature’s neuroscience, this so -called “learning machine” speaks in two different codes, one for recently acquired movements and another for “natural” innate behaviors. These surprising findings of laboratory rats can shed light on human movement disorders such as Parkinson’s disease.

“When we compare the codes with these two domains of behavior, we found that they were very different,” said Bence Ölveczky, a professor of organism and evolutionary biology (OEB).

“They had nothing to do with each other. Both faithfully reflected the animal’s movements, but the language was deeply different.”

Located in the middle mentioned under the cerebral cortex, the basal ganglia are involved in the reward, emotion and motor control. This region is also the site of some of our most infamous movement disorders: Parkinson’s disease, Huntington’s disease and Tourette’s syndrome, all arise from different defects of basal ganglia.

Although for a long time it is known that basal ganglia play a central role in motor control among mammals, it is not clear if this part of the brain directs all movements or simply those for specialized tasks.

Some researchers postulate that acts as a learning locus for movements acquired through practice, but not other routine behaviors. Other scholars argue that he plays a role in all movements.

To shed light on this mystery, the researchers analyzed a particular part of the basal ganglia in rats: the dorsolateral striated body (DLS), which plays a role in the behaviors learned.

The team studied rats during two different activities: free exploration and a learned task in which they were trained to press a lever twice inside a specific time interval to obtain a reward. To track their movements, the equipment used a six -chamber system around the enclosure plus a software system that classified behaviors.

In previous studies, the team eliminated the DLS of the rats, who later showed no differences in free exploration, demonstrating that the DLS did not play any role in natural behaviors such as walking or preparing. But the animals themselves were deeply affected by performing tasks learned, revealing that the DLS was essential for newly acquired skills.

“There was a massive change, like night and day,” said Kiah Hardcastle, postdoctoral member in the Ölveczky Laboratory and main author of the new study, on the previous work. “The animal could do a super task, performing a repeated stereotyped movement, about 30,000 times. Then, injury, the DLS and never make that movement again.”

In the new study, the researchers sought to understand neuronal activity during these behaviors, implementing small electrodes in the brain of the rats and registering the electric shot of the neurons while participating in the free exploration and the task learned.

To their surprise, they discovered that the basal ganglia used two different kinematic codes, or patterns of neuronal electrical activity, during the task learned and natural movements.

“It is as if the basal ganglia” speak “different languages when the animal performs movements learned versus innate,” said Ölveczky. “The downstream brain areas that the control movement only knows one of these languages, which is spoken during the behaviors learned.”

The researchers concluded in the document that the basal ganglia changed the round trip “between being an essential actor and a mere observer.”

Hardcastle speculated that basal ganglia may not be able to completely turn off the electrical signage by not directing the behavior to change to a “null code” harmless.

Ölveczky said that findings can be informative about humans because it is believed that structures under the cerebral cortex were largely kept preserved during evolutionary time.

He believes that the study shows that basal ganglia play essential roles in the movements learned, but not necessarily in routine motor control. He also believes that findings offer clues about what can go wrong in some disorders of human movement.

“Our research suggests that the pathology associated with that of Parkinson’s can be understood as the sick basal nodes that speak, but in a very strong and forceful way,” said Ölveczky. “Therefore, it is inserted, not sensitively, in behaviors that would otherwise not control.”

On this neuroscience research news

Author: Kermit Pattison
Source: Harvard
Contact: Kermit Pattison – Harvard
Image: The image is accredited to Neuroscience News

Original research: open access.
“Differential kinematic coding in the striated body sensoriomotor in behavioral domains reflects different contributions to the” Kiah Hardcastle et al. Nature neuroscience

Abstract

Differential kinematic coding in the sensor -foothold striated body in behavior domains reflects different contributions to the movement

The sensoriomotor arm of the basal ganglia is an important part of the mammal engine control network, however, if it admits all movements or specialized for tasks -oriented behaviors, it still does not be clear.

To examine this, we probe the contributions of the striated rat sensoriomotor (dorsolateral striated (DLS)) in two behavioral domains: free exploration, in which naturalistic behaviors are expressed and during a motor task.

Unlike the previous work, which showed that the DLS was essential to generate specific tasks learned movements, DLS lesions had no effect on naturalistic behaviors such as breeding, preparation or walking.

To explore the neural base of this functional dissociation, we compare DLS activity in the two domains. Although neural activity reflected the kinematics of movement in both, kinematic codes differ clearly.

These findings suggest that the basal sensoriomotor nodes are not essential parts of mammalian motor control, but rather, they change their output to a powerful engine space to shape the specific behaviors of the task.