Scientists discover what happens in our brains when we make educated
guesses

Date:
September 17, 2020
Source:
UK Research and Innovation
Summary:
Researchers have identified how cells in our brains work together
to join up memories of separate experiences, allowing us to make
educated guesses in everyday life. By studying both human and mouse
brain activity, they report that this process happens in a region
of the brain called the hippocampus.



FULL STORY ========================================================================== Researchers have identified how cells in our brains work together to
join up memories of separate experiences, allowing us to make educated
guesses in everyday life. By studying both human and mouse brain activity,
they report that this process happens in a region of the brain called
the hippocampus.


==========================================================================
The study, published in the scientific journal Cell, also reveals that
brain cells can link different memories while we are resting or sleeping,
a process that may be important in creativity.

The research was funded by the Medical Research Council (MRC), part of
UK Research and Innovation (UKRI), and Wellcome, and was carried out
at the MRC Brain Network Dynamics Unit at the University of Oxford,
by Dr Helen Barron and Dr David Dupret.

Dr Barron said: "In everyday life we often infer connections or
relationships between different things we see or hear. So even
when we don't know the full story, we can make an educated guess by joining-the-dots. For example, I'm looking for my friend Sam. Someone
tells me that Ben is in the library. I know that Sam and Ben go everywhere together, so I guess that Sam is in the library too.

"Although this process is crucial to everyday life, until now, we didn't
know how the cells in our brains are able to form links between separate experiences." The researchers began by pinpointing this ability to an
area of the brain called the hippocampus that is already known to play
a role in learning and memory. They did this using MRI scans on people
and by temporarily switching off the hippocampus in mice.



==========================================================================
To discover precisely how brain cells enable us to make educated guesses,
the researchers ran a set of very similar experiments in people and mice.

Human volunteers were asked to play a virtual reality game where hearing
a sound, such as running water, signalled that the volunteers would also
see a colourful picture appear on the wall.

They would then play another game where finding the colourful pictures
would help them win money. The sound was never directly connected to
winning money, yet the volunteers began to guess that the sound was linked
to the prize and when they heard it, they would look for the reward.

The experiment was recreated in mice by playing a sound before showing
a picture made from LED lights. Then, in a separate stage of the task,
the mice could find a reward of sugar water if the lights were turned
on. Like the people, the mice began connecting the sound with the reward.

Dr Dupret said: "By carrying out similar experiments with both mice and
people, this work shows that the process of establishing a link between separate events is common to both species. And by working with mice,
it's then possible to examine what's going on in the brain of a mammal
at the level of individual cells." In mouse brains, the researchers
could record the activity of brain cells that individually represented
sounds, lights or rewards. As the mice began to infer that a sound was logically linked to the reward via a light, they found that the cells
began to fire in that order.



========================================================================== However, they kept monitoring the mice when they rested after completing
the task and they saw that the mice's brains began jumping over the intermediate 'light' step. The 'sound' brain cells became active with the 'reward' brain cells; joining the dots between different experiences.

Dr Dupret added: "This suggests that while the mice are resting,
their brains are making new links between things they have not
directly experienced together, and we think it's this process that
will help them make useful decisions in the future." Dr Barron said:
"Our results suggest the process is very similar in people and that has important implications. It suggests that periods of rest and sleep play
an important role in creativity, where we draw insight from previous
experience to come up with original ideas." Dr Simon Fisher, Programme
Manager for the Neurosciences and Mental Health Board at the MRC, added:
"Our ability to put individual memories together to form new links helps
us make day-to-day decisions. This study provides insight into how and
where in the brain this key process takes place. It also suggests that
while we are sleeping or resting, our brains are actively making these
links, a process that may form the basis of creative thinking.

"This strong approach, of working with mice alongside comparable
experiments with people, allows findings from one species to inform
studies in the other and enhances the translation of biological knowledge
from animal models through to humans.


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


========================================================================== Journal Reference:
1. Helen C. Barron, Hayley M. Reeve, Rene'e S. Koolschijn, Pavel V.

Perestenko, Anna Shpektor, Hamed Nili, Roman Rothaermel, Natalia
Campo- Urriza, Jill X. O'Reilly, David M. Bannerman, Timothy
E.J. Behrens, David Dupret. Neuronal Computation Underlying
Inferential Reasoning in Humans and Mice. Cell, 2020; DOI:
10.1016/j.cell.2020.08.035 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200917181253.htm

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