Reprogramming brain cells enables flexible decision-making

Date:
September 16, 2020
Source:
University of Zurich
Summary:
Humans, like other animals, have the ability to constantly adapt to
new situations. Researchers have utilized a mouse model to reveal
which neurons in the brain are in command in guiding adaptive
behavior. Their new study contributes to our understanding of
decision-making processes in healthy and infirm people.



FULL STORY ========================================================================== Humans, like other animals, have the ability to constantly adapt to new situations. Researchers at the Brain Research Institute of the University
of Zurich have utilized a mouse model to reveal which neurons in the
brain are in command in guiding adaptive behavior. Their new study
contributes to our understanding of decision-making processes in healthy
and infirm people.


========================================================================== Greetings without handshakes, mandatory masks in trains, sneezing into
elbow crooks -- the COVID-19 pandemic dramatically illustrates how
important it can be for humans to shed habitual behaviors and to learn
new ones. Animals, too, must be capable of rapidly adapting to changes
in environmental conditions.

"The plasticity of the brain forms the foundation of this ability,"
says Fritjof Helmchen, the co-director of the Brain Research Institute
at the University of Zurich, who also heads the Neuroscience Center
Zurich. "But the biological processes that enable this amazing feat
are still poorly understood." Helmchen's team has now successfully
taken a first step towards illuminating these processes. Their study,
just published in the scientific journal Nature, demonstrates that the orbitofrontal cortex, a region of the cerebral cortex that sits behind
the eyes, is capable of reprogramming neurons located in sensory areas.

Observing brain cells in the act of relearning In their experiments with
mice, the researchers simulated a relearning process under controlled conditions and investigated what happens in the brain at the level of individual neurons during that process. The researchers first trained
the animals to lick every time they touched a strip of coarse-grit
sandpaper with their whiskers and rewarded the response with a drink of
sucrose water.

However, the mice were not allowed to lick when they brushed their
whiskers against fine-grain sandpaper; if they did, they were punished
with a mild irritating noise. Once the mice understood how to perform
their task, the tables were then turned. The reward was now delivered
after whisking against fine-grain and not coarse-grit sandpaper. The mice quickly learned this new, opposite behavior pattern after little practice.

A higher authority remaps cells During the training, the neuroscientists employed molecular biological and imaging techniques to analyze the
function of individual neurons in the brain cortices involved. Their
analysis revealed that a group of brain cells in the orbitofrontal cortex
is particularly active during the relearning process.

These cells have long axons that extend into the sensory area in
mice that processes tactile stimuli. The cells in this area initially
followed the old activity pattern, but some of them then adapted to the
new situation. When specific neurons in the orbitofrontal cortex were deliberately inactivated, relearning was impaired and the neurons in
the sensory area no longer exhibited modification in their activity.

"We were thus able to demonstrate that a direct connection from the orbitofrontal cortex to sensory areas of the brain exists and that
some neurons get remapped there," explains Helmchen. "The plasticity
of those cells and the instructions they receive from the higher-order orbitofrontal cortex appear to be crucial to behavioral flexibility and
our ability to adapt to new situations." "It has long been known that
the orbitofrontal cortex is involved in decision- making processes." It
is in charge, to a certain degree, of enabling us to react appropriately
and successfully to exogenous circumstances. "But the neural circuits underlying this function were unknown until now," says Abhishek Banerjee,
lead author of the study, now an Associate Professor at Newcastle
University, UK. "This mode of communication and control across distant
areas of the brain is truly remarkable." Understanding disorders better
The researchers believe that the fundamental processes they observed
in mice take place in a similar way in the human brain as well. "This
deepened knowledge about complex brain processes involved in decision
making is important," explains Helmchen. "Our research findings may
contribute to a better understanding of brain disorders in which the flexibility in decision making is impaired, as it is, for example in
various forms of autism and schizophrenia." Clearly, he says, having difficulties or being unable to adapt one's behavior poses a severe
problem for affected people.


========================================================================== Story Source: Materials provided by University_of_Zurich. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Abhishek Banerjee, Giuseppe Parente, Jasper Teutsch, Christopher
Lewis,
Fabian F. Voigt, Fritjof Helmchen. Value-guided remapping of sensory
cortex by lateral orbitofrontal cortex. Nature, 2020; 585 (7824):
245 DOI: 10.1038/s41586-020-2704-z ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200916113510.htm

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