What does "brain tired" mean? What happens to nerve cells when overexertion occurs? Why do long-term mental work cause temporary cognitive impairments?

2 Answers

1. At the heart of the brain is the transmission of impulses from one neuron to another, through the axon. In turn, impulses arise as a result of the appearance of an action potential, which is caused by potassium and sodium ions. With prolonged and intense mental work, the membranes of neurons enter a state of absolute refractoriness, that is, these cells are not able to respond to impulses for some time, due to overloading. As a result, there is a certain dissonance in the work of the brain.

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2. In addition to the answer of N NUR-MUKHAMMED ORMANOV, I want to add the following.�

   Brain fatigue, particularly in humans and higher animals, is mainly caused by the activity of synapses, that is, the junction of two nerve cells. The problem is that synaptic transmission of nerve impulses occurs with the help of so-called mediators, i.e. chemicals (for example, such as acetylcholine, norepinephrine). It looks like this: the nerve impulse has reached the place of its transmission to another cell, and substances-mediators should be released from the first cell, which will be perceived by the second cell. The nerve impulse goes further as a result.

   So, the supply of these mediators in the cell is limited, during its continuous operation there comes a time when the supply of them is depleted, and the brain needs time of inactivity to replenish the supply (i.e., simply sleep). We feel this as fatigue, a desire to rest (sleep).

   And in the end, I want to say that our brain is smart precisely because we have a lot of these synaptic connections between brain cells, and therefore we get tired and need to sleep.

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