How the brain processes the number zero How the brain processes the number zero

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2024-09-26 01:00:06

Despite its importance for mathematics, the neuronal basis of the number zero in the human brain was previously unknown. Researchers from the University Hospital Bonn (UKB), the University of Bonn and the University of Tübingen have now discovered that individual nerve cells in the medial temporal lobe recognize zero as a numerical value and not as a separate category "nothing". The results have now been published in the journal "Current Biology".

The concept of the number zero has been central to the development of number systems and mathematics and is widely regarded as one of humanity's most important cultural achievements. "Unlike other numbers such as one, two or three, which represent countable quantities, zero means the absence of something countable and at the same time still has a numerical value," says co-corresponding author Prof. Florian Mormann from the Department of Epileptology at the UKB, who is also a member of the Transdisciplinary Research Area (TRA) "Life & Health" at the University of Bonn. In contrast to positive natural numbers, the concept of the number zero only emerged late in human history over the last two millennia. This is also reflected in childhood development, as children are typically only able to understand the concept of zero and associated arithmetic rules at around the age of six.

How this concept is represented by nerve cells in the human brain has not yet been investigated. The researchers from Bonn have now joined forces with neurobiologists from the University of Tübingen to get to the bottom of this question. To do this, they showed neurosurgical patients, who had had hair-thin microelectrodes inserted into their temporal lobes at the UKB in preparation for surgery, numerical values from zero to nine. The numerical values were shown as Arabic numerals on the one hand and as sets of dots on the other - including an empty set. "Meanwhile, we were able to measure the activity of individual nerve cells and actually found neurons that signaled zero," says Esther Kutter, who is the first author of the study. "Such neurons responded to either the Arabic numeral zero or the empty set, but not to both."