Switching learning on

December 12, 2013, Friedrich Miescher Institute for Biomedical Research
Switching learning on
Learning in basket cells

Neurobiologist from the Friedrich Miescher Institute for Biomedical Research show how a network of neurons in hippocampus and cortex switches states to turn on and off learning in the adult. They further show how a stimulating environment promotes this switch, and thus learning. Their findings are published today in the renowned journal Nature and have far reaching implications also for diseases where learning and memory is impaired, such as Alzheimer's or dementia.

Learning to ride a bike, to ski or swim: After many days and weeks of practice, trial and error, we usually master a skill and never forget how to do it. What is also common knowledge is that motivation and a supportive environment usually help: learning how to ski in the extreme cold will take much longer than on a sunny day with an understanding teacher. While we can observe these phenomena over and over again with many tasks at hand, we still don't understand fully, what mechanisms in the brain first enable learning and then allow the switch to the state where "we just know", and hardly forget.

Pico Caroni and his team at the Friedrich Miescher Institute for Biomedical Research in Basel could now show that networks of specific cells in the brain regions relevant for each particular type of learning, switch first to a "learning state" and then to a "learnt state", and how the environment and experience modulate these processes.

In a study published today in the renowned scientific journal Nature, they could show that so called basked cells, inhibitory neurons assembled in a network to modulate the function of excitatory neurons in brain regions such as the hippocampus, switch between three states during a learning experience. From a neutral state, many basket cells de-differentiate as the starts. This facilitates local formation and remodeling of new connections, new synapses; the network is plastic and conducive to learning and memory of new relationships potentially important to master the task at hand.

As soon as the task has been successfully learned, this initial switch is reversed, and many basket cells switch to a highly differentiated state. The local network loses its ability to form new synapses, but at the same time enhances the function of strong synapses involved in the newly learned skill; the network loses its plasticity, but consolidates its gains. Learning is complete, the ability to perform the task stable.

Finally, the cells revert to the neutral state again, ready for the next task to learn.

Caroni and his team further showed that the learning environment influences the state of the basket cells. In an environment rich in stimuli and diverse experiences, a large fraction of the basket cells are in a low differentiation state, ready for learning. Importantly, the scientists show that they can pharmacogenetically switch the different basket cells, thereby inducing the predicted outcomes in the ability to learn. Inhibition of basket cells decreased their differentiation and increased the ability to learn, whereas activation of basket cells increased their differentiation state and reduced learning and memory skills.

These findings are ground-breaking in several ways. First, for a long time the scientific community believed that plasticity of neuronal connections in such as the hippocampus is permanently reduced in the adult. Caroni and his team now show that the same cells that ease learning and plasticity of neuronal connections in the young are involved in the same processes at an older age. Second, the scientists could show how the environment and experience influence plasticity and learning. "In dementia and Alzheimer's disease, stimulating activities have been proposed as therapeutic approaches to slow down the disease," comments Caroni, "our results provide now a scientific rational for such a therapeutic tactic. Being able to reversibly induce basket cell network states that modulate and memory formation might be harnessed for therapeutic strategies in these diseases."

Explore further: Specific regions of the hippocampus connected to discrete steps of task mastery, study finds

More information: "Parvalbumin-expressing basket-cell network plasticity induced by experience regulates adult learning." Flavio Donato, Santiago Belluco Rompani & Pico Caroni. Nature 504, 272–276 (12 December 2013) DOI: 10.1038/nature12866 . Received 03 May 2013 Accepted 05 November 2013 Published online 11 December 2013

Related Stories

Specific regions of the hippocampus connected to discrete steps of task mastery, study finds

October 1, 2012
(Medical Xpress)—In a study published in Nature Neuroscience, neurobiologists from the Friedrich Miescher Institute for Biomedical Research have been linking synapse formation in the hippocampus to distinct learning steps. ...

Scientists discover brain structures associated with learning

May 2, 2011
(Medical Xpress) -- Scientists at the Friedrich Miescher Institute for Biomedical Research (FMI, part of the Novartis Research Foundation) have discovered neuronal connections which are formed in the brain when learning occurs, ...

Learning and memory: How neurons activate PP1

November 4, 2013
A study in The Journal of Cell Biology describes how neurons activate the protein PP1, providing key insights into the biology of learning and memory.

Brain: Balancing old and new skills

December 9, 2013
To learn new motor skills, the brain must be plastic: able to rapidly change the strengths of connections between neurons, forming new patterns that accomplish a particular task. However, if the brain were too plastic, previously ...

New learning and memory neurons uncovered

April 11, 2013
(Medical Xpress)—A University of Queensland study has identified precisely when new neurons become important for learning.

Recommended for you

Research reveals atomic-level changes in ALS-linked protein

January 18, 2018
For the first time, researchers have described atom-by-atom changes in a family of proteins linked to amyotrophic lateral sclerosis (ALS), a group of brain disorders known as frontotemporal dementia and degenerative diseases ...

Fragile X finding shows normal neurons that interact poorly

January 18, 2018
Neurons in mice afflicted with the genetic defect that causes Fragile X syndrome (FXS) appear similar to those in healthy mice, but these neurons fail to interact normally, resulting in the long-known cognitive impairments, ...

How your brain remembers what you had for dinner last night

January 17, 2018
Confirming earlier computational models, researchers at University of California San Diego and UC San Diego School of Medicine, with colleagues in Arizona and Louisiana, report that episodic memories are encoded in the hippocampus ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

Midbrain 'start neurons' control whether we walk or run

January 17, 2018
Locomotion comprises the most fundamental movements we perform. It is a complex sequence from initiating the first step, to stopping when we reach our goal. At the same time, locomotion is executed at different speeds to ...

Neuroscientists suggest a model for how we gain volitional control of what we hold in our minds

January 16, 2018
Working memory is a sort of "mental sketchpad" that allows you to accomplish everyday tasks such as calling in your hungry family's takeout order and finding the bathroom you were just told "will be the third door on the ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Protoplasmix
1 / 5 (1) Dec 12, 2013
I was going to ask if underutilization of the basket cells can result in the condition referred to as being a 'basket case.' Uh, no—after checking on the origin of that phrase I see it's a perfectly gruesome reminder that war is good for the economy (of the basket weaver).

I think the soft-switch-combo for eidetic memory can be elucidated by this research—excellent work so far. Because some things should ne'er be forgot more than others.
katesisco
not rated yet Dec 15, 2013
Every 7 years every cell in your body including your brain is replaced. So it would seem good health is in our reach, stop sugar, flouride, chlorine, pharma, rancid oils, and drink distilled water. Good luck.

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.