How does the brain do arithmetic? Both addition and subtraction methods have special neurons, and the symbol text can activate the same group of cell sub journals

Yang Jing From the Aofei temple
qubits | official account QbitAI

What the brain does is a mathematical problem ？

Until recently , Scientists have the answer ——

Specialized “ Mathematical neurons ”.

When performing calculations , Some neurons are active in addition , But when the brain subtracts , Another wave of neurons became active .

And whether you see mathematical symbols , Or on the 、 Subtracted text .

Once encountered , Can summon neurons to work .

The relevant research of Tubingen University and Bonn University is on the Cell Sub issue Current Biology.

Let's see what kind of research this is .

The brain does arithmetic ？

Previous studies have shown that , The little monkey has neurons in its brain that are specifically used to calculate rules .

But there is no data on the human brain .

Based on this background , The research team carried out relevant exploration .

Simply speaking , This experiment is in the brain MTL（ Hippocampus and its cortex ） Micro electrodes are implanted in the area , Ask volunteers to add and subtract , Test their neuronal activity .

Volunteers are 9 Epilepsy patients , among 4 Men , The average age is 43.3 year .

Because in these patients , Seizures always originate in the same area of the brain MTL, In order to accurately locate the defect area , The doctor has implanted multiple electrodes into the patient .

Benefit from such a premise , The researchers chose 9-10 Clinical Behnke-Fried Deep electrodes are used to record neuronal signals , Each depth electrode contains a bundle of nine platinum iridium microelectrodes , The tip protrudes about 4 mm .

During the experiment , Volunteers sit in bed . At about 50 At a distance of CM , There is a touch-screen laptop .

Numbers are displayed on the screen in turn （ Or dot ） And symbols , The volunteers then selected the results from the numeric keypad , Then there is a computer display “ correct ” still “ error ”.

There are... In the middle of every two displays 800 Millisecond delay ; Each subject has a total of 320 A test consists of , And divide into 4 Group . front 10 This test is considered as a rehearsal , Not included in subsequent analysis .

Different neurons are active alternately

The researchers recorded MTL A total of... In the area 585 The action potential of a single neuron ：

Parahippocampal cortex (PHC) Medium 126 Neurons 、 The hippocampus (HIPP) Medium 199 Neurons 、 Entorhinal cortex (EC) Medium 107 Neurons and amygdala (AMY) There is 153 Neurons .

And input the whole action mode into a self-learning computer program .

Based on multivariate analysis of variance , Firstly, rule selective neurons are determined .

What does that mean ？

These neurons after the calculation instruction is issued （ That is, add or subtract ） Will selectively enhance the discharge .

You can see , In the figure A、B In the case of addition rules , Additive neuron （ Red ） The specific activity shown .C、D（ Blue ） The same is true of the subtractive neurons shown .

And different for task cycle and MTL Area , The proportion of selective neurons is also different .

besides , The team also found that the coding of the calculation rule is independent of the rule prompt , And in the parahippocampal cortex (PHC) Area （ chart I）, Different addition neurons are in the same arithmetic task Alternating activity .

Researchers describe , It's like the plus key on a calculator is constantly changing its position . The same is true of subtraction .

Department of epilepsy, Bonn University Hospital Mormann Says Professor , This research marks an important step in understanding the mathematical calculation of the brain .

Next, they want to understand what role these neurons play .

Thesis link ：
https://www.cell.com/current-biology/fulltext/S0960-9822(22)00116-6#secsectitle009000116-6#secsectitle0090)

GitHub link ：
https://github.com/EstherKutter/Neuronal-Codes-For-Arithmetic-Rule-Processing-In-The-Human-Brain

Reference link ：
[1]https://www.uni-bonn.de/en/news/028-2022