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Jakarta, Spami-id.com - heavy physical work is obviously exhausting, but the sweat in someone's forehead or his vibrating muscles doesn't show how hard they think.
19th-century American writer Wallace D. Wattles once said that "Thinking is the hardest and most exhausting of all jobs."
That statement may sound like a controversial comparison, but a new study suggests that thinking too hard and too long can actually drain your brain, just as sports can make the body tired.
When someone says they're mentally exhausted, we just have to do what they say. As a result, scientists still don't fully understand why intense thinking causes cognitive exhaustion.
That cognitive fatigue does not cause the effects of a sleepy feeling, it's the sensation that makes us feel that the task is increasingly difficult to solve or focus.
Some researchers now suspect that the stimuli of glutamate as neurotransmitters (molecules or chemical messaging in the body that sends signals or messages from neurons to neurons to target cells) which are so abundant in the brain is the cause of the lack of mental endurance.
Glutamate is a new stimulated amino acid described precisely in the 1950s, despite the fact that it's present in over 90 percent of neurological communication to the neurons in the human brain.
For decades, these underrated chemicals continue to surprise scientists. The neurons, for example, have been found to control their signal power in the brain by regulating the amount of glutamate that they release to other neurons. Glutamate can even stimulate neurons to death, with as many as 8,000 glutamate molecules packed in one pocket of synapse, the intersection where two neurons meet.
Glutamate is obviously a problem, and that's part of the reason why glutamate is linked to a drained brain.
When monitoring the brain chemistry of 24 participants who were assigned to complete heavy computer-based sorting tasks for over six hours, researchers found the glutinal increase in lateral prefrontal cortex. It's a brain part associated with high-level cognitive powers, like short-term memory and decision-making.
By comparison, 16 other participants who were given easier tasks for that day showed no signs of glutamate accumulation in their brain. Thus, researchers think the increase in extra-cellular glutamate may at least be one of the factors of human mental resistance.
Obviously, the brain also gobbled up a lot of glucose at work. Another theory suggests that this energy source might be another barrier factor, but it's still unclear how the loss of glucose makes thinking harder, biochemistry.
Some researchers have proposed that the loss of glucose triggers dopamine loss in the brain, which makes one lose interest in certain cognitive tasks easier.
"Effective theory suggests that fatigue is a sort of illusion made by the brain to make us stop whatever we're doing and move on to more satisfying activities," clearly the clinical psychologist Mathias Pessiglione from Pitié-Salpètrière University in Paris, France.
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Pessiglione also says there's good evidence that glutamate was removed from synapses during sleep. That could be part of the reason why a night rest can make someone feel mentally refreshed the next day.
Sebuah studi pencitraan otak pada tahun 2016 yang menggunakan MRI fungsional (fMRI), juga menemukan korteks prefrontal lateral (lPFC) terlibat dalam upaya kognitif intens yang mengurangi rangsangannya dari waktu ke waktu. Untuk mengaktifkan wilayah ini, di akhir hari yang panjang dan berat akan membutuhkan lebih banyak usaha daripada di awal. Oleh karena itu, perasaan menguras otak.
“Diambil bersama dengan data fMRI sebelumnya, hasil ini mendukung model neuro-metabolik di mana akumulasi glutamat memicu mekanisme regulasi yang membuat aktivasi lPFC lebih mahal, menjelaskan mengapa kontrol kognitif lebih sulit untuk dimobilisasi setelah hari kerja yang berat,” Pessiglione dan rekan menyimpulkan.
Glutamat adalah neurotransmitter yang bekerja sangat cepat. Itu bagian dari apa yang membuat asam amino itu begitu kuat, tetapi itu juga membuat bahan kimia sulit untuk diukur. Studi seperti saat ini memanfaatkan teknologi baru untuk mengeksplorasi peran cepat glutamat di otak kita secara lebih rinci.
Para penulis sekarang berharap untuk menyelidiki mengapa glutamat terakumulasi begitu banyak di korteks prefrontal dibandingkan dengan bagian lain dari otak. (sumber: Science Alert dari Current Biology)
