A unique brain signal may be the key to human intelligence

Though progress is being made, our brains remain organs of many mysteries. Among these are the exact workings of neurons, with some 86 billion of them in the human brain. Neurons are interconnected in complicated, labyrinthine networks across which they exchange information in the form of electrical signals. We know that signals exit an individual neuron through a fiber called an axon, and also that signals are received by each neuron through input fibers called dendrites.

Understanding the electrical capabilities of dendrites in particular — which, after all, may be receiving signals from countless other neurons at any given moment — is fundamental to deciphering neurons’ communication. It may surprise you to learn, though, that much of everything we assume about human neurons is based on observations made of rodent dendrites — there’s just not a lot of fresh, still-functional human brain tissue available for thorough examination.

For a new study published January 3 in the journal Science, however, scientists got a rare chance to explore some neurons from the outer layer of human brains, and they discovered startling dendrite behaviors that may be unique to humans, and may even help explain how our billions of neurons process the massive amount of information they exchange.

A puzzle, solved?

Electrical signals weaken with distance, and that poses a riddle to those seeking to understand the human brain: Human dendrites are known to be about twice as long as rodent dendrites, which means that a signal traversing a human dendrite could be much weaker arriving at its destination than one traveling a rodent’s much shorter dendrite. Says paper co-author biologist Matthew Larkum of Humboldt University in Berlin speaking to LiveScience, “If there was no change in the electrical properties between rodents and people, then that would mean that, in the humans, the same synaptic inputs would be quite a bit less powerful.” Chalk up another strike against the value of animal-based human research. The only way this would not be true is if the signals being exchanged in our brains are not the same as those in a rodent. This is exactly what the study’s authors found.

The researchers worked with brain tissue sliced for therapeutic reasons from the brains of tumor and epilepsy patients. Neurons were resected from the disproportionately thick layers 2 and 3 of the cerebral cortex, a feature special to humans. In these layers reside incredibly dense neuronal networks.

Without blood-borne oxygen, though, such cells only last only for about two days, so Larkum’s lab had no choice but to work around the clock during that period to get the most information from the samples. “You get the tissue very infrequently, so you’ve just got to work with what’s in front of you,” says Larkum. The team made holes in dendrites into which they could insert glass pipettes. Through these, they sent ions to stimulate the dendrites, allowing the scientists to observe their electrical behavior.

In rodents, two type of electrical spikes have been observed in dendrites: a short, one-millisecond spike with the introduction of sodium, and spikes that last 50- to 100-times longer in response to calcium.

In the human dendrites, one type of behavior was observed: super-short spikes occurring in rapid succession, one after the other. This suggests to the researchers that human neurons are “distinctly more excitable ” than rodent neurons, allowing them to successfully traverse our longer dendrites.

In addition, the human neuronal spikes — though they behaved somewhat like rodent spikes prompted by the introduction of sodium — were found to be generated by calcium, essentially the opposite of rodents.

An even bigger surprise

The study also reports a second major finding. Looking to better understand how the brain utilizes these spikes, the team programmed computer models based on their findings. (The brains slices they’d examined could not, of course, be put back together and switched on somehow.)

The scientists constructed virtual neuronal networks, each of whose neurons could could be stimulated at thousands of points along its dendrites, to see how each handled so many input signals. Previous, non-human, research has suggested that neurons add these inputs together, holding onto them until the number of excitatory input signals exceeds the number of inhibitory signals, at which point the neuron fires the sum of them from its axon out into the network.

However, this isn’t what Larkum’s team observed in their model. Neurons’ output was inverse to their inputs: The more excitatory signals they received, the less likely they were to fire off. Each had a seeming “sweet spot” when it came to input strength.

What the researchers believe is going on is that dendrites and neurons may be smarter than previously suspected, processing input information as it arrives. Mayank Mehta of UC Los Angeles, who’s not involved in the research, tells LiveScience, “It doesn’t look that the cell is just adding things up — it’s also throwing things away.” This could mean each neuron is assessing the value of each signal to the network and discarding “noise.” It may also be that different neurons are optimized for different signals and thus tasks.

Much in the way that octopuses distribute decision-making across a decentralized nervous system, the implication of the new research is that, at least in humans, it’s not just the neuronal network that’s smart, it’s all of the individual neurons it contains. This would constitute exactly the kind of computational super-charging one would hope to find somewhere in the amazing human brain.

Link Original:https://bigthink.com/neuropsych/human-neuron-signals/#Echobox=1635050448

Pupil size surprisingly linked to differences in intelligence

What can you tell by looking into someone’s eyes? You can spot a glint of humor, signs of tiredness, or maybe that they don’t like something or someone. 

But outside of assessing an emotional state, a person’s eyes may also provide clues about their intelligence, suggests new research. A study carried out at the Georgia Institute of Technology shows that pupil size is «closely related» to differences in intelligence between individuals. 

The scientists found that larger pupils may be connected to higher intelligence, as demonstrated by tests that gauged reasoning skills, memory, and attention. In fact, the researchers claim that the relationship of intelligence to pupil size is so pronounced, that it came across their previous two studies as well and can be spotted just with your naked eyes, without any additional scientific instruments. You should be able to tell who scored the highest or the lowest on the cognitive tests just by looking at them, say the researchers.

The pupil-IQ link

The connection was first noticed across memory tasks, looking at pupil dilations as signs of mental effort. The studies involved more than 500 people aged 18 to 35 from the Atlanta area. The subjects’ pupil sizes were measured by eye trackers, which use a camera and a computer to capture light reflecting off the pupil and cornea. As the scientists explained in Scientific American, pupil diameters range from two to eight millimeters. To determine average pupil size, they took measurements of the pupils at rest when the participants were staring at a blank screen for a few minutes.

Another part of the experiment involved having the subjects take a series of cognitive tests that evaluated «fluid intelligence» (the ability to reason when confronted with new problems), «working memory capacity» (how well people could remember information over time), and «attention control» (the ability to keep focusing attention even while being distracted). An example of the latter involves a test that attempts to divert a person’s focus on a disappearing letter by showing a flickering asterisk on another part of the screen. If a person pays too much attention to the asterisk, they might miss the letter. 

The conclusions of the research were that having a larger baseline pupil size was related to greater fluid intelligence, having more attention control, and even greater working memory capacity, although to a smaller extent. In an email exchange with Big Think, author Jason Tsukahara pointed out, «It is important to consider that what we find is a correlation — which should not be confused with causation.»

The researchers also found that pupil size seemed to decrease with age. Older people had more constricted pupils but when the scientists standardized for age, the pupil-size-to-intelligence connection still remained.

Why are pupils linked to intelligence?

The connection between pupil size and IQ likely resides within the brain. Pupil size has been previously connected to the locus coeruleus, a part of the brain that’s responsible for synthesizing the hormone and neurotransmitter norepinephrine (noradrenaline), which mobilizes the brain and body for action. Activity in the locus coeruleus affects our perception, attention, memory, and learning processes.

As the authors explain, this region of the brain «also helps maintain a healthy organization of brain activity so that distant brain regions can work together to accomplish challenging tasks and goals.» Because it is so important, loss of function in the locus coeruleus has been linked to conditions like Alzheimer’s disease, Parkinson’s, clinical depression, and attention deficit hyperactivity disorder (ADHD).

The researchers hypothesize that people who have larger pupils while in a restful state, like staring at a blank computer screen, have «greater regulation of activity by the locus coeruleus.» This leads to better cognitive performance. More research is necessary, however, to truly understand why having larger pupils is related to higher intelligence. 

In an email to Big Think, Tsukahara shared, «If I had to speculate, I would say that it is people with greater fluid intelligence that develop larger pupils, but again at this point we only have correlational data.»

Do other scientists believe this?

As the scientists point out in the beginning of their paper, their conclusions are controversial and, so far, other researchers haven’t been able to duplicate their results. The research team addresses this criticism by explaining that other studies had methodological issues and examined only memory capacity but not fluid intelligence, which is what they measured.

Link Original: https://bigthink.com/surprising-science/pupil-size-intelligence

Avalon evolutive School

Você já ouvir falar de growth mindset 🤔?.Este termo, atualmente muito usado em empresas, aparece pouco nas escolas. Agora, imagine… Como seria se tivéssemos sido ensinados uma das coisas mais importantes do desenvolvimento humano: que é possível aprender qualquer coisa se o seu modelo mental for de possibilidades 😃..➡️ A inteligência é algo construído, onde a pessoa se prepara para perceber. Cada nova percepção é uma nova inteligência. Isso quer dizer melhoria contínua, não há o conceito de “erro” como tal, apenas de: “o que eu ainda não observei, não percebi, o que eu ainda não sei”. Mas que posso observar, perceber e saber, se me dedicar e treinar minhas capacidades para isso. . A palavra chave do growth mindset é “ainda”, que coloca a criança dentro da curva de aprendizagem, com autoestima e confiança. O que eu não sei ainda, posso saber ✅.

Ética profunda: o longo caminho para distinguir o certo do errado

Na série The Good Place, um professor de filosofia chamado Chidi tenta ajudar seus colegas de vida após a morte a se tornarem pessoas melhores, apresentando a eles algumas questões morais e éticas com as quais os filósofos se preocupam. Entre elas, o clássico “dilema do bonde”: 

“Imagine que você está dirigindo um bonde desgovernado e no trilho à sua frente estão cinco operários que você vai atropelar. Você tem a opção de mudar a direção do trem, o que resultaria na morte de uma única pessoa que está no outro trilho, em vez dos cinco operários. O que você faz?» 

Para o azar de Chidi, ele é imediatamente colocado na situação de estar efetivamente dirigindo um bonde sem freio e precisa decidir o que vai fazer – a verdade é que ele não consegue.

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why writing by hand makes kids smarter

Photo by Julia M Cameron on Pexels.com

Writing by hand creates much more activity in the sensorimotor parts of the brain, researchers found

October 1, 2020 / Norwegian University of Science and Technology

Summary:New brain research shows that writing by hand helps children learn more and remember better. At the same time, schools are going more and more digital, and a European survey shows that Norwegian children spend the most time online of 19 countries in the EU.

Professor Audrey van der Meer at NTNU believes that national guidelines should be put into place to ensure that children receive at least a minimum of handwriting training.

Results from several studies have shown that both children and adults learn more and remember better when writing by hand.

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How «thinking about thinking» can help children in school and in life

In simple terms, metacognitive thinking teaches us about ourselves. According to Tamara Rosier, a learning coach who specializes in metacognitive techniques, thinking about our thinking creates a perspective that allows us to adapt and change to what the situation needs.

A simple example of metacognitive thinking (or reframing) is this:

«Math tests make me anxious.» This is a statement, a thought. Turning to metacognition, this train of thought evolves into «What about math tests make me anxious…and what can do I to change that?»

According to Rosier, children who are taught to think of themselves as being either «good» or «bad» at a particular task can end up with a fixed mindset that makes them passive in approaching a challenge relating to that task. However, teaching kids to become more metacognitive helps them develop a mindset that leaves more room for growth and adaptation, promoting self-awareness and resilience.

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Artificial Intelligence System Learns the Fundamental Laws of Quantum Mechanics







Artificial Intelligence can be used to predict molecular wave functions and the electronic properties of molecules. This innovative AI method developed by a team of researchers at the University of Warwick, the Technical University of Berlin and the University of Luxembourg, could be used to speed-up the design of drug molecules or new materials.

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