Nerve cell activity shows how confident we are

October 09, 2020

Should I or shouldn't I? The activity of individual nerve cells in the brain tells us how confident we are in our decisions. This is shown by a recent study by researchers at the University of Bonn. The result is unexpected - the researchers were actually on the trail of a completely different evaluation mechanism. The results are published in the journal Current Biology.

You are sitting in a café and want to enjoy a piece of cake with your cappuccino. The Black Forest gateau is just too rich for you and is therefore quickly eliminated. Choosing between the carrot cake and the rhubarb crumble is much trickier: The warm weather favors the refreshingly fruity cake. Carrot cake, however, is one of your all-time favorites. So what to do?

Every day we have to make decisions, and we are much more confident about some of them than others. Researchers at the University Hospital Bonn have now identified nerve cells in the brain whose activity indicates the confidence in decisions. A total of twelve men and women took part in their experiment. "We showed them photos of two different snacks, for example a chocolate bar and a bag of chips," explains Prof. Dr. Dr. Florian Mormann from the Department of Epileptology. "They were then asked to use a slider to indicate which of these alternatives they would rather eat." The more they moved the slider from its center position towards the left or right photo, the more confident they were in their decision.

Fire rate and confidence are related

Participants had to judge a total of 190 different snack pairs in this way. At the same time, the scientists recorded the activity of 830 nerve cells each in the so-called temporal lobe. "We discovered that the frequency of the electrical pulses in some neurons, in other words their 'firing rate', changed with increasing decision confidence," explains Mormann's colleague Alexander Unruh-Pinheiro. "For instance, some fired more frequently, the more confident the respective test person was in their decision."

It is the first time that such a correlation between activity and decision confidence has been identified. The affected neurons are located in a brain region that plays a role in memory processes. "It is possible that we not only store what decision we made, but also how confident we were in it," speculates Mormann. "Perhaps such a learning process saves us from future wrong decisions."

Ethical reasons usually prohibit the study of the state of individual neurons in living humans. However, the participants in the study suffered from a severe form of epilepsy. In this form of the disease, the characteristic seizures always start in the same area of the brain. One possible treatment is therefore to remove this epileptic focus surgically. To pinpoint the exact location of the defective site, the doctors at the Clinic for Epileptology implant several electrodes in the patient. These are distributed over the entire potentially affected area. At the same time, they also allow an insight into the functioning of individual nerve cells in the brain.

Researchers at the University of Bonn were originally looking for a completely different phenomenon: When we make a decision, we assign a subjective value to each of the alternatives. "There is evidence that this subjective value is also reflected in the activity of individual neurons," says Mormann. "The fact that we instead came across this connection between fire behavior and decision confidence surprised even us."
-end-
Publication: Alexander Unruh-Pinheiro, Michael R. Hill, Bernd Weber, Jan Boström, Christian E. Elger, Florian Mormann: Single Neuron Correlates of Decision Confidence in the Human Medial Temporal Lobe. Current Biology; dx.doi.org/10.1016/j.cub.2020.09.021

Contact:

Prof. Dr. Dr. Florian Mormann
Klinik für Epileptologie
Universitätsklinikum Bonn
Tel. +49-228-28715738
E-mail: florian.mormann@ukbonn.de

University of Bonn

Related Neurons Articles from Brightsurf:

Paying attention to the neurons behind our alertness
The neurons of layer 6 - the deepest layer of the cortex - were examined by researchers from the Okinawa Institute of Science and Technology Graduate University to uncover how they react to sensory stimulation in different behavioral states.

Trying to listen to the signal from neurons
Toyohashi University of Technology has developed a coaxial cable-inspired needle-electrode.

A mechanical way to stimulate neurons
Magnetic nanodiscs can be activated by an external magnetic field, providing a research tool for studying neural responses.

Extraordinary regeneration of neurons in zebrafish
Biologists from the University of Bayreuth have discovered a uniquely rapid form of regeneration in injured neurons and their function in the central nervous system of zebrafish.

Dopamine neurons mull over your options
Researchers at the University of Tsukuba have found that dopamine neurons in the brain can represent the decision-making process when making economic choices.

Neurons thrive even when malnourished
When animal, insect or human embryos grow in a malnourished environment, their developing nervous systems get first pick of any available nutrients so that new neurons can be made.

The first 3D map of the heart's neurons
An interdisciplinary research team establishes a new technological pipeline to build a 3D map of the neurons in the heart, revealing foundational insight into their role in heart attacks and other cardiac conditions.

Mapping the neurons of the rat heart in 3D
A team of researchers has developed a virtual 3D heart, digitally showcasing the heart's unique network of neurons for the first time.

How to put neurons into cages
Football-shaped microscale cages have been created using special laser technologies.

A molecule that directs neurons
A research team coordinated by the University of Trento studied a mass of brain cells, the habenula, linked to disorders like autism, schizophrenia and depression.

Read More: Neurons News and Neurons Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.