June 16, 2024

Counting Conundrum – Nerve Cells Can Detect Small Numbers of Things Better Than Large Numbers of Things

There seem to be two distinctive methods in which we as people tend to process numbers of things: We are usually able to find small numbers of things really rapidly and correctly. Some researchers have therefore speculated that there are two various processing techniques in the brain– an accurate one for small numbers and an estimate system for larger numbers of things. The research study groups included in the project were able to show some years ago that the brain has nerve cells accountable for each number. When a brain cell for a number of 3 things fires, it concurrently hinders the brain cells for the numbers two and four. After that, the number of errors increased with the number of dots, as did the quantity of believing time that the participants needed to complete their job.

Utilizing ultrafine electrodes implanted in the temporal lobes of epilepsy clients, scientists can imagine the activity of single nerve cells in various brain areas. Credit: Christian Burkert/Volkswagen Foundation/University of Bonn
Some researchers have actually therefore hypothesized that there are two various processing approaches in the brain– an exact one for little numbers and an estimation system for larger varieties of things. “However, this idea has been challenged already,” describes Prof. Florian Mormann from the Department of Epileptology at the University Hospital Bonn, who performs research at the University of Bonn. “It could also be that our brain always makes an estimate but the mistake rates for smaller numbers of things are so low that they merely go undetected.”
The neurons for smaller varieties of things are more selective
The current research study in fact suggests, however, that we do certainly procedure big and little numbers of things in a different way. The research groups associated with the task had the ability to demonstrate some years ago that the brain has afferent neuron accountable for each number. Some neurons fire, for instance, mostly for two components, others for four components, and again others for 7 components. “However, the nerve cells also fire in reaction to slight variations in the number,” discusses Prof. Andreas Nieder from the University of Tübingen, who was the other main author of the research study together with Mormann. “A brain cell for a number of “7” components therefore likewise fires for 6 and eight aspects however more weakly. The exact same cell is still triggered however even less so for 5 or 9 aspects.”
After a brief pause they had to indicate whether the number had been even or odd. If the number of dots was less than five, they generally offered the right response without hesitation.
Nieder has actually currently had the ability to demonstrate this “numerical distance effect” in experiments on monkeys. Surprisingly, this result only appears to happen in human beings at greater numbers. “There seems to be an additional system for numbers of around less than 5 elements that makes these neurons more exact,” says the neurobiologist.
When a brain cell for a variety of three things fires, it all at once prevents the brain cells for the numbers two and four. This decreases the threat that these cells will also improperly fire for the number 3. This mechanism does not exist for the nerve cells triggered for numbers 5, 6 or 8. This is why there is a greater mistake rate for these numbers.
Observing private brain cells at work
A special feature of the University Hospital Bonn benefited the scientists in their research study: The Department of Epileptology at the healthcare facility specializes in brain surgery. The medical professionals there try to treat epilepsy by performing operations to remove the diseased nerve tissue. In order to identify the place of the epileptogenic focus, they often first insert electrodes into the impacted persons brain.
Seventeen clients participated in the current study. In preparation for their operations, microelectrodes as great as a human hair were inserted into the temporal lobe. “We were able to utilize them to determine the reaction of private nerve cells to visual stimuli,” discusses Esther Kutter, who brought out a large proportion of the experiments for her doctorate in the research group headed by Prof. Mormann.
The test topics were seated in front of a computer screen on which various numbers of dots appeared for half a second. The participants were then asked to state whether they had seen an even or odd number of dots. They had the ability to react extremely rapidly and made virtually no errors up to a number of four dots. After that, the number of errors increased with the variety of dots, as did the amount of believing time that the participants required to finish their job.
This work will open new insights into how numbers are processed in the human brain. In the long term, the findings could lead to a much better understanding of dyscalculia, a developmental disorder related to a bad understanding of numbers.
Recommendation: “Distinct neuronal representation of small and large numbers in the human median temporal lobe” by Esther F. Kutter, Gert Dehnen, Valeri Borger, Rainer Surges, Florian Mormann and Andreas Nieder, 2 October 2023, Nature Human Behaviour.DOI: 10.1038/ s41562-023-01709-3.
Getting involved institutes and funding: The University of Tübingen, the University of Bonn, and the University Hospital Bonn took part in the research study. The research study was funded by the German Research Foundation (DFG), the German Federal Ministry for Education and Research (BMBF) and the iBehave Research Network in the State of North Rhine-Westphalia.

Human beings rapidly identify small numbers (as much as four) but struggle with larger ones. Recent research exposes the brain has distinct mechanisms for processing little versus big quantities. When neurons are firing, the brain waveforms show. Credit: Christian Burkert/Volkswagen-Stiftung/University of Bonn
Research study performed in Tübingen and Bonn has determined proof of 2 different processing systems.
The brain does in fact register smaller sized numbers of things in a different way than larger ones. Recent research, conducted by the University of Tübingen, University of Bonn, and University Hospital Bonn, reveals that the brain processes smaller sized quantities in a different way than bigger ones.
Imagine that someone reveals us an image of a string quartet and asks us to state the number of individuals there are in the picture. There is not adequate time to count them however we can all answer like a shot: “Four!” The next photo shows a septet and again we are only offered sufficient time to take a glimpse. We hesitate and are not rather so confident this time: “Eight.” The right number is really seven but we were extremely close.
There seem to be 2 unique ways in which we as humans tend to process numbers of things: We are usually able to discover little numbers of things really rapidly and properly. This is likewise referred to as “subitizing” in research circles. This technique modifications unexpectedly when there are five elements or more: We require more and more time to respond to and our answers become significantly inaccurate.