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How exactly does the brain do math problems?
It's only recently that scientists have the answer —
There are specialized "mathematical neurons".
When performing calculations, some neurons are active when adding, but when the brain does subtraction, another wave of neurons begins to be active.
And whether you see mathematical symbols, or add or subtract words.
Once encountered, neurons can be summoned to work.
Research from the University of Tübingen and the University of Bonn has appeared in the Cell sub-journal Current Biology.
Let's see what kind of research this is.
Does the brain do arithmetic problems?
Previous studies have shown that monkeys have specific neurons in their brains that are used to calculate rules.
But there is no data on the human brain.
Based on this background, the research team conducted relevant explorations.
In simple terms, the experiment was to implant miniature electrodes in the MTL (hippocampus and its cortex) region of the brain, and let the volunteers do addition and subtraction to test their neuronal activity.
The volunteers were 9 epileptic patients, 4 of whom were men, with an average age of 43.3 years.
Because in these patients, the seizures always originate in the same area of the brain MTL, in order to pinpoint the defective area, the doctor has implanted multiple electrodes into the patient.
Benefiting from such a premise, the researchers chose 9-10 clinical Behnke-Fried depth electrodes to record neuronal signals, each containing a beam of nine platinum iridium microelectroles with the tip protruding about 4 mm.
During the experiment, the volunteers sat on the bed. At a distance of about 50 cm, there is a touch screen laptop.
The screen displays numbers (or dots) and symbols in turn, after which volunteers select the calculation results from the numeric keypad and a computer displays "correct" or "wrong".
There was a delay of 800 milliseconds in between each of the two displays; each subject consisted of a total of 320 trials, divided into 4 groups. The first 10 trials were considered rehearsals and were not counted in subsequent analyses.
Different neurons alternately active
The researchers recorded the action potentials of a total of 585 individual neurons in the MTL region:
There are 126 neurons in the hippocampal paracortic (PHC), 199 neurons in the hippocampus (HIPP), 107 neurons in the inner olfactory cortex (EC), and 153 neurons in the amygdala (AMY).
And enter the entire motion mode into a self-learning computer program.
Based on multivariate ANOVA, regularly selective neurons are first identified.
What does that mean?
These neurons selectively enhance firing after the computational instruction is issued (i.e., to add or subtract).
It can be seen that in the case of the addition rules of A and B in the figure, the addition neurons (red) show specific activity. The same is true of the subtractive neurons represented by C and D (blue).
And for the task cycle and the MTL region, this selective proportion of neurons also varies.
In addition to this, the team also found that the encoding of the computational rules was independent of the rule cue, and that in the hippocampal paracortex (PHC) region (Figure I), different addition neurons alternately active in the same arithmetic task.
The researchers describe it as if the plus key on a calculator is constantly changing its position. The same goes for subtraction.
Professor Mormann, from the Department of Epilepsy at the University Hospital of Bonn, said the study marked an important step in understanding the mathematical calculations of the brain.
The next step is to understand exactly what role these neurons play in this.
Thesis Link:
https://www.cell.com/current-biology/fulltext/S0960-9822(22)00116-6#secsectitle009000116-6#secsectitle0090)
GitHub Links:
https://github.com/EstherKutter/Neuronal-Codes-For-Arithmetic-Rule-Processing-In-The-Human-Brain
Reference Links:
[1]https://www.uni-bonn.de/en/news/028-2022