The Brain Is 100% Active

Español

Português

Did We only Use 10% of our Brain? (3)
The Brain Is 100% Active!

Neuroscience findings now show that the brain is 100% active. In neurosurgery, when it is possible to observe the functions of the brain on patients under local anaesthetic, electric stimulations show no inactive areas, even when no movement, sensation, or emotion is being observed.


No areas of the brain are completely inactive, even during sleep; if they were, it would indicate a serious functional disorder.




Similarly, loss of very much less than 90% of brain tissue leads to serious consequences as no region of the brain can be damaged without causing physical or mental defects.

The cases of people who have lived for years with a bullet lodged in the brain or similar trauma do not indicate “useless areas”. If it is possible to completely recover from such a shock, it is the demonstration of the brain’s extraordinary plasticity: neurons (or networks of neurons) have been able to replace those that were destroyed and in such cases the brain reconfigures itself to overcome the defect.



The myth is implausible for physiological reasons, too. Evolution does not allow waste and the brain, like the other organs but probably more than any other, is moulded by natural selection. It represents only 2% of the total weight of the human body but consumes 20% of available energy. With such high energy cost, evolution would not have allowed the development of an organ of which 90% is useless.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 113

Did We only Use 10% of our Brain? (2)

Español

Português

Did We only Use 10% of our Brain? (2)
The 10% of Brain's Cells Are Neurons

The primary areas are surrounded by secondary areas, so that, for example, information from images perceived by the eye is sent to the primary visual areas, and then is analysed in the secondary visual areas where the three-dimensional reconstitution of the perceived objects takes place.
Information from the memory of the subject circulate in the brain to recognise objects, while semantic information from language areas comes into play so that the person can quickly name the object seen.

At the same time, the brain areas that deal with posture and movement are in action under the effect of nerve signals from the entire body, allowing the person to know whether (s)he is sitting or standing, with the head turned to the right or the left, etc. . Therefore, a partial, fragmented description of the areas of the brain can lead to a misinterpretation of how it works.

The 10% of Neural Brain's Cells Are Neurons

Another origin of the myth may be found in the fact that the brain is made up of ten glial cells (neuroglia) for every neuron. Glial cells have a nutritional role and support nerve cells, but they do not transmit any information. In terms of transmission of nerve impulses only the neurons are recruited (or 10% of the cells comprising the brain) so that this offers a further source of misunderstanding on which the “10% myth” might come.

But this vision of cell functions is simplistic: while the glial cells play a different role from that of the neurons, they Are No Less essential to the functioning of the whole.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 113

Did We Only Use 10% of our Brain?

Español

Português

Did We only Use 10% of our Brain?

It is often said that humans only use 10% (sometimes 20%) of their brain. Where did this myth come from? Some say it came from Einstein, who responded once during an interview that he only used 10% of his brain. Early research on the brain may have supported this myth.

In the 1930s, Karl Lashley explored the brain using electric shocks. As many areas of the brain did not react to these shocks, Lashley concluded that these areas had no function. This is how the term “silent cortex” came into circulation. This theory is now judged to be incorrect. Dubious interpretations of the brain’s functioning have also fuelled this myth.





Today, thanks to imaging techniques, the brain can be precisely described in functional areas. Each sense corresponds to one or several primary functional areas: a primary visual area, which receives information perceived by the eye; a primary auditory area, which receives information perceived by the ear, etc.

Several regions are linked to the production and comprehension of language. They are sometimes described separately by physiologists, and the public which remembers these partial descriptions may gain the impression that the brain functions area by area. This would be consistent with the image that, at any one moment, only a small region of the brain is active but this is not what occurs.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 113

In The Man There Are NOT Critical Periods To Learning

Español

Português

Are There Critical Periods to Learning? (2)
In Learning: The Birds Have Critical Periods, The Man Has Sensitive Periods

The concept of "Critical Period" dates back to experiments conducted in the 1970s by the ethologist Konrad Lorenz which are relatively well-known by the general public.

He observed that fedglings on hatching became permanently attached to the prominent mobile object of the environment, usually their mother, which attachment Lorenz named as “Imprinting”. By taking the place of the mother, Lorenz managed to become attached to fledglings which followed him everywhere. The period that allows this attachment is very short (right after hatching); once in place, it was impossible to change the attachment object and the fledglings permanently followed the substitute instead of their mother. The term “Critical Period” is appropriate for such a case as an event (or its absence) during a specific period brings about an irreversible situation.



The acquisition of skills results from training and the strengthening of certain connections, but also from pruning certain others. There is a distinction that needs to be drawn between two types of synaptogenesis – the one that occurs naturally early in life and the other resulting from exposure to complex environments throughout the lifespan. Researchers refer to the first as “Experience-Expectant Learning” and to the second as “Experience-Dependent Learning”.

Grammar is learned faster and easier up to approximately age 16, while the capacity to enrich vocabulary actually improves throughout the lifespan (Neville, 2000).

Grammar gives an example of sensitive-period learning and is experience-expectant: for learning to be done without excessive difficulty, it must ideally take place in a given lapse of time (the sensitive period). Experience-Expectant Learning is thus optimal during certain periods of life.

Learning that does not depend on a sensitive period, such as the acquisition of vocabulary, is “Experience-Dependent”: when the learning best takes place is not constrained by age or time and this type of learning can even improve as the years go by.

Are there “Critical Periods” as unique phases during which certain types of learning can only successfully take place? Can certain skills or even knowledge only be acquired during relatively short “windows of opportunity” which then close once-and-for-all at a precise stage of brain development?

"Understanding the Brain", The Birth of a Learning Science, 2007, page 113

When Certain Matters Must be Learnt?

Español

Português

Are There Critical Periods to Learning? (1)

When Certain Matters Must be Taught and Learnt?

The influence of the intense synaptogenesis early in life on the adult brain is not yet known, but it is known that adults are less capable of learning certain things. Anyone who starts to learn a foreign language later in life, for example, will in all likelihood always have a “foreign accent”; the virtuosity of a late learner of an instrument will in all probability never equal that of a child practised with the same musical instruction from the age of 5.

Does this mean that there are periods of life when certain tasks can no longer be learned? Or are tasks merely learned more slowly or differently at different times?

For a long time it was believed that the brain loses neurons with age, but the measures opened by new technologies have challenged this certainty. Terry and his colleagues showed that the total number of neurons in each area of the cerebral cortex is not age-dependent but only the number of “large” neurons. Nerve cells shrink, resulting in a growing number of small neurons but the aggregate number of all neurons remains the same.

Certain parts of the brain, like the hippocampus, have recently been found actually to generate new neurons throughout the lifespan. The hippocampus is, among other things, involved in spatial memory and navigation processes (Burgess and O’Keefe, 1996).

Research comparing London taxi drivers with random other citizens suggests a strong relationship between the relative size and activation of the hippocampus, on the one hand, and a good capacity for navigation, on the other; there is a positive correlation between the enlargement of the auditory cortex and the development of musical talent, as there is growth of motor areas of the brain following intense training of finger movements. In the latter case, changes in the neuron network configuration linked to the learning could be measured using brain imaging from the fifth day of training, i.e. after an extremely brief period of learning.

The processes that remodel the brain – neuron synaptogenesis, pruning, development, and modification – are grouped together under the same term: “Brain Plasticity”. Numerous studies have shown that the brain remained plastic throughout the lifespan, in terms of numbers of both neurons and synapses.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 112