Chronotype and Learning

Learning process is a complex group of factors that depends of genetic and environmental influences, and one of them seems to be the chronotype, which is defined as a propensity of a person to sleep at a particular time during a circadian period.

Even if is usual to believe that habits can make a difference between students, since they learn to adapt their findings from a chronobiology perspective highlight a deeper molecular accent into how can humans can handle changes of light, from a evolutionary point of view. Life on planet in general is sensible to changes called cycles. One of them is known as Circadian rhythms.

Circadian rhythms are approximate 24-h biological cycles that prepares an organism for daily environmental changes, driven by molecular clocks that basically are a trasncriptional-translational feedback mechanism that involves the core clock genes in mammals and it is present in virtually all cells of an organism ¹.

Roenneberg, Kuehnle, Pramstaller, Ricken, Havel, Guth, and Merrow², explain that chronotype “depends on genetic and environmental factors but also on age”, and at the same that some other authors add gender to the landscape ³.

Chronotype changes with age, and some researchers have found systematical differences between children and adolescents, showing that children are early chronotypes and change slowly but progressively until delay and reaching a maximum of diurnal preferences around the age of 20, which suggests the end of adolescence³. However, the chronotype will change again with increasing age.

Adolescents’ circadian clocks typically run late⁴, they love to sleep until late and it’s easy to believe this is related with a crazy nightlife. However, different studies shows that in fact, these diurnal preferences can be something due circadian timing system. One explanation leads to endocrine factors, since hormones begin to run around adolescents systems for example studies how a time of day dependent of growth hormones which reaches its maximum and cortisol a minimum at around 1 am².

These changes are associated with two different situations, one medical and one related with academic performances.

From a medical perspective, aging is associates with sleep problems, including earlier awakening and a decrease of sleep patterns, mainly finding problems to consolidate sleep during the night⁵.

With this is mind is clear it can be explained an academic situation that many students suffer: sleep difficulties affect the way their learnings are consolidated. For example Pincher and Walters⁷, studied the performance of 44 students who had to complete the Watson-Glaser-Critical Thinking Appraisal after either 24 hours of sleep deprivation or approximately 8 hours of sleep. In this study, after completing the cognitive task, participants with sleep deprivation performed significantly worse than the non-deprived participants. Other studies have found very similar results even using different tests^8-12.

All these studies show a relationship between sleep and academic performance and most of studies have focused on medicine students¹² since they have the worst problems about morningness-eveningness so it’s easy to see the influence on learning, particularly of college students.

However, another issue must be add to this puzzle, It seems there is a relationship between age and activities and how they push to persons to create more and more gaps between sleep timing on workdays and weekends which is knows as social jetlag which can be described as the discrepancy between work and free days, this means a difference between social and biological time, leading to a considerable sleep debt ¹⁴.

The term social jetlag was coined in 2006 by researchers at Ludwig-Maximilians University in Munich, Germany, who wanted to know the effects caused by differences between person’s internal biological clocks and the social clock time.

This social jetlag has been of course related with poor academic performances, and some studies like the one conduced by Haraszti, Ella, Gyöngyösi, Roenneberg, and Káldi¹⁵ suggests than circadian misalignment can have a significant negative effect on academic performance and they suggest that this is socially enforced.

Considering all these factors, education has much more to considerate for a successful environment to most of students. Late schedules to   older students based on their chronotype, and of course personal habits that can be broken easily with social activities effect how learning can be performance.

References

1.                Harfmann, BD., Schroder, EA., Esser, KA. (2014) Circadian Rhythms, the molecular clock, and skeletal muscle. Journal of Biological Rhythms. doi: 10.1177/0748730414561638

2.   Roenneberg, T., Kuehnle, T., Pramstaller, PP., Ricken, J., Havel, M., Guth, A., Merrow, M. (2004) A marker for the end of adolescence. Current Biology, 14(24) R1038-R1039.

3.   Randle, C. (2010) Age and gender differences in morningness-eveningness during adolescence. Journal of Genetic Psychology: Research and Theory on Human Development, 172(3) 302-308.

4.   Van der Vinne, V., Zerbin, G., Siersemat, A., Pieper, A., Merrow, M., Hut, RA., Roenneberg, T., Kantermann, T. (2014) Timing examinations affects school performance differently in early and ate chronotypes. Journal of Biological Rhythms. doi: 10.1177/0748730414564786

5.   Duffy, J., Czeisler, CA. (2002) Age-related change in the relationship between circadian period, circadian phase, and diurnal preference in humans. Neuroscience letters, 318(3) 117-120.

6.   Buboltz, WC., Brown, F., Soper, B. (2001) Sleep habits and patters of college students: A preliminary study. Journal of American College Health, 50(3) 131-135

7.   Pincher, JJ., & Walters, AS. (2007) How sleep deprivation affects psychological variables related to college students’ cognitive performance. Journal of American College Health. 46 (3)121-126.

8.   Curcio, G., Ferrara, M., De Gennaro, L.(2006) Sleep loss, learning capacity and academic performance, Sleep Medicine Reviews.10(5) 323-337.

9.   Woltson, AR., Carskadon, MA. (2003) Understanding adolescent’s sleep patterns and school performance: a critical appraisal. Sleep Medicine Reviews 7(6) 491-506.

10.                Pilcher, J., Ginter, DR., Sadowsky, B. (1997) Sleep quality versus sleep quantity: Relationships between sleep and measures health, well-being and sleepiness in college students.  Journal of Psychosomatic Research. 42(6) 583-596.

11.                Randler, C.,  & Frech, D. (2006) Correlation between morningness-eveningness and final school leaving exams. Biological Rhythm Research, 37(3) 233-239.

12.                Medeiros, ALD., Mendes, DBF., Lima, P., & Araujo, JF. (2001) The relationship between sleep-wake cycle and academic performance in medical students. Biological Rhythm Research, 32(2) 263-270.

13.                Haraszti, RA., Ella, K., Gyöngyösi, N., Roenneberg, T., and Káldi, K. (2014) Social jetlag negatively correlates with academic performance in undergraduates. Chronobiology International, 31(5) 603-612.

14.                Wittman,, M., Dinich, J., Merrow, M., Roenneberg, T. (2006) Social Jetlag: Misalignment of biological and social time. Chronobiology international, 23(2) 497-509.

15.                Haraszti, RA., Ella, K., Gyöngyösi, N., Roenneberg, T., and Káldi, K. (2014) Social jetlag negatively correlates with academic performance in undergraduates. Chronobiology International, 31(5) 603-612.

 Note: All images were taken from internet

The search for talent: the Holy Grail

There is a  common idea,  noticeable from psychologists and educational experts, about put  labels to learners and give them a place in an imaginary continuous line that cluster outstanding skills in the right side and educational needs at the left side.

If it's looked the continuum, everybody at the left or right requires special education or supports, and at this case, it must be admitted that not everyone learns the same way. But a second glance, suggests that all who are in the middle of the curve, have no problem.

Certainly there is no more pride for  parents that their child can be declared as gifted, while there is no greater grief than when someone tells them that their child will not be able to learn more than  few skills. The rest of the parents clean the sweat when their stems are declared as normal, not having this any other implication beyond what a psychologist says.

Going deep into this subject, there is much more that experts do not report.

The forward of the book La educación de niños con talento en Iberoamerica (Education of gifted children at Ibero-America) opens saying, "All people are entitled to receive an education that develops their full potential and allow them to build a life plan" (Benavides, Maz, Castro and White, 2004).

With  this idea, then it is clear that those who are at  the left side of the  curve would have the opportunity to develop skills while those who have the right side can not move beyond, since they know more than anybody else, they have reached the maximum their abilities based on scales of talent.

The text describes programs, ideas and notes about  how to work with  talented children in several countries, but if these children are the greatest intellectual achievement, is it possible to teach even more?.

The talent from psychology

In the purest psychometric eagerness has been measured the intelligence and the possible capabilities, searching to find those common features on the continuum of the curve of intelligence. For those who are at the left, it was assumed that lack the intellectual, emotional or social skills to relate with those who are at the center of the continuum (Winner, 1998; Artigas Pallares, 2003, Martos and Help 2004). While those who are at the right have a high intellectual capacities measured with psychometric instruments (Pendarvis, Howley & Howley, 1990; Lohman, 2000; Lohman, Korb and Lakin, 2008). But they lack the emotional skills to adapt to those who have left or center of the continuum (Genovard and Castello, 1990; Freeman, 2005; Freeman, 2008; Freeman, 2010).

But not everything that intelligence tests measure is useful to adapting to the environment: for example there are important aspects of the real-world intelligence that are not considerate. On the other hand there is a debate if that perspective is confusing intelligence with rationality, issues that do not necessarily go hand by hand (Stanovich, 2009). That's why even the smartest people can do things that are considered irrationals. At the same time, psychometric tests forget an important feature of the brain: emotions (Freeman, 2008). This aspect has been widely documented as the primary difficulty in children considered talented.

Stanovich (2009) shows that there are features such as divergent thinking or aspects of the  everyday life that have nothing to do with what psychological tests measure, moreover, when students have the opportunity  to reply  to problems, it may surprise to expertise researchers, for example, when gifted children can talk to  others about science and feel good by providing creative answers, beyond which we have assumed is the only one correct answer ( Freeman, 2003), or when a child, considered with limited capacity, achieved a task for which he or she has worked for several hours. And  those that are supposed are  the differences, actually are the result of the brain architecture, which is molded with repetition and experimenting with  the environment  (Manaut-Gil-Casares Vaquero, Quintero-Gallego, Pérez-Santamaría, Gomez-Gonzalez, 2004).

Thus, from the speech of educational experts that sounds so melodious, the obvious question is: IF "All persons are entitled to receive an education that develops their full potential and allow them to build their project of life", Why is segmented the continuum?, Why can we have only one position?, Why can't be together?, maybe to create an elite education?.

From the standpoint of Renzulli (1978) the differences between the continuum are not only concentrated in one area as many authors propose (Parra, Ferrando, Prieto and Sanchez, 2005; Rogers, 2006; Valadez Sierra, Betancourt Berbena Morejon and Zavala, 2006) they are determined from different skills set out in three areas: high intelligence, creativity and involvement in the task.

Can a child with Down syndrome or Asperger be creative?, If your reply at the speed of light that does not, then please do not continue reading this article,  you are not creative. Creativity involves providing innovative responses to common problems. And it's not a mystery that daily work requires creativity and divergent thinking abilities, however, this is not developed at educational institutions at basic or higher level (Solomon, 2007).

Considering its capacity, each new brain must be trained to grow from environmental stimulation; a process that needs decades and each person must discover for itself all skills needed to be employed on that journey called Life (Tubino, 2004). And it doesn't depend of any curricula or educative legislation.

Accepting that the human brain still evolving (Fox, 2011), depends on synaptic communication, the development of structures and protein exchanges neurotransmitters (Haier, 2009), makes learning a more complex issue than just locate someone on one side or the other of an imaginary line, and open a door to understand that learning is not something that can be X-rayed by a test applied at a specific time.

Neuroscience research suggests that human abilities depend on the neural network architecture, which is related to the space where the brain develops, as it is confined to the skull, shaping each structure in a particular way, some areas can be over-exposed to stimuli preventing the development of other areas, under two assumptions: the law of survival of the fittest and its use related with environmental responses (Roberts, Anderson, Husain, 2010). So that it’s not possible to talk about standardized education and less, support the idea that everyone learns the same way.

And it must be added the fact that there are other actors in education, research showing that success in the case of gifted children, has a big support of maternal scaffolding, that makes the difference between passing from a skill to another (Morrisey, 2011) and the same from mother of children with developmental disorders, since they are who promote socialization skills in their kids, if there is any doubt, it's only needed one question:  who did teach you how keep attention while reading?.

Talent does not equal intelligence

The talent or giftedness refers to that ability or skill set which has a particular facility (Prado Suarez, 2006), but the definition of any author, never says that it is restricted to the fine arts or science or sports. If so, where do entrepreneurial talent, or create or play video games fall?.

Intelligence is adaptation to the environment (Genovard and Castello, 1990; VanTassel-Baska, Xuemei Feng, Brown, Bracken, Stambaugh, French, McGowan, Worley, Quek and Bai, 2008), an action that requires talent. Though not necessarily arrive together, this worth mentioning, for example that as highlighted in the Savant, which is a developmental disorder that is part of the autistic spectrum. Main feature of this syndrome is that people can have a widely talent developed at the same time a profound intellectual difficulty (Winner, 1998).

Thus, it is argued that the provision of skills of each person, although it has a genetic aspect, at the same time depends on environmental stimulation (Willard-Holt, 2008).  Every one can have a special talent for playing the piano in an extraordinary way, but if you never had a piano in front, the talent can not be developed. That's why experience shapes capacities that will be most useful. However, genetic damage as those presented in the development disorders also shape brain structure.

Brain studies reveal that the patterns of gray and white matter and metabolic efficiency may delineate individual differences related to intelligence. That's why the smartest brains work differently (not better) in the strongest areas that has a better domain (Haier, 2009).

What structures will be more developed?, those that are  used more frequently, and that is because of the skills that create, cause more satisfaction in completing tasks. That feeling of: I can do it (Prado Suarez, 2006). However, under the law of the strongest, the strengthened  structures, will push and eventually block the development of the  other less useful  (Haier, 2009) which is why you can not be expert in everything, because the skills will be permeated by the use and management of them.

In the case of arithmetic, it’s found that the frontal lobe is more involved in this activity, and also opens the path to memory processes and analytical thinking (Serra-Grabulosa, Pérez-Pàmies, Lachica, Membrives, 2010), Even though, a good mathematician not necessarily is a good writer of poetry or have social skills. Einstein maybe is a good example.

Conclusion

In conclusion, it can be said that the differences in the continuum that psychologists have called intelligence, is simply due to the cytoarchitecture of the brain and that it results from interactions, and this determines the capabilities that each possesses. Starting from the extreme neuronal flexibility that, that which is not known today, can be learned from the appropriate teaching strategy, which may be different for each depending on experience.

Under the motto: “Everyone is entitled to receive an education that develops their full potential and allow them to build their project to life", there shouldn’t be distinction what side of that continuum is, left, right or in the middle, all people have the ability to build a life project, based on their own abilities and who is not able to tie your shoes, you may have the ability to paint pretty colorless pictures.

Academic skills are not the only ones that are valid in life; there are also artistic and sporting activities. There are sports stars, who have not reached higher education, but they have adapted to environmental needs and above all, they are happy.

Under this idea, the separation of the continuum although it may have educational benefits, it makes no sense neuro cognitively, and that all people have the right to find a place in life, a happy childhood and successful adulthood.

Alma Dzib Goodin

If you would like to know more about my writing you can visit my web site:
http://www.almadzib.com

References

Artigas Pallarés, J. (2003) Perfiles cognitivos de la inteligencia límite. Fronteras del retraso mental. Rev Neurol. 36 (supl 1) S161-S167.

Benavides, M., Maz, A., Castro, E. y Blanco, R. (2004) La educación del niños con talento en Iberoamérica. UNESCO/Trineo SA. Chile.

Fox, D. (2011) The limits of intelligence. Scientific American. 305 (1) 36- 43.

Freeman, J. (2010) Worldwide provision to develop gifts and talents: an international survey. CfBT Education Trust. UK.

Freeman, J. (2008) The emotional development of the gifted and talented. Gifted and talented provision. Optimus Educational. London.

Freeman, J. (2005) Counseling the gifted and talented. Journal Gifted Education International. 19. 245-252.

Freeman, J. (2003) Scientific thinking in gifted children. In P. Csermely & L. Lederman (Eds) Scientific Education: Talent recruitment and public understanding. IOS Press with NATO Scientific Affairs Division. Amsterdam.

Haier, RJ. (2009) What does a smart brain look like?. Scientific American Mind. 20 (6) 26-33.

Genovard, C. y Castelló, A. (1990) El límite superior. Aspectos psicopedagógicos de la excepcionalidad intelectual. Pirámide. Madrid.

Lohman, D. F. (2000) Complex information processing and intelligence. En R. J. Sternberg (Ed.) Handbook of intelligence. Cambridge University Press. Cambridge, UK.

Lohman, DF.,  Korb, K.A. y  Lakin, JM. (2008) Identifying Academically Gifted English- Language Learners Using Nonverbal Tests A Comparison of the Raven, NNAT, and CogAT. Gifted Child Quarterly. 52  (4). 275-296.

Manaut-Gil, E. Vaquero-Casares, E. Quintero-Gallego, E. Pérez-Santamaría, J. Gómez-González, C.M (2004) Relación entre el déficit neurológico y el cociente de inteligencia en niños y adolescentes. Rev Neurol. 38 (1): 20-27.

Martos, J. y Ayuda, R. (2004) Desarrollo temprano: algunos datos procedentes del autismo y los trastornos del lenguaje. Rev Neurol. 38 (supl 1) S39-S46.

Morrisey, AM (2011) Maternal scaffolding of analogy and metacogtnition in the early pretence giften children. Exceptional children. 77 (3) 351-366.

Parra, J. Ferrando, M., Prieto, MD. y Sánchez, C. (2005) Características de la producción creativa en los niños con altas habilidades. Sobredotaçao, 6, 77-98.

Pendarvis, E., Howley, A., & Howley, C. (1990) The abilities of gifted children. Prentice Hall. USA.

Prado Suarez, RC. (2006) Creatividad y sobredotación: Diagnóstico e intervención psicopedagógica. Creatividad y Sociedad. 9. 110-120.

Renzulli, J. S. (1978) What makes giftedness? Re-examining a definition. Phi Delta Kappan, 60, 180- 184.

Roberts, R.E., Anderson, E. J., Husain, M. (2010) Expert Cognitive Control and Individual Differences Associated with Frontal and Parietal White Matter Microstructure. The Journal of Neuroscience. 30(50): 17063-17067.

Rogers, C. (2006) Niños superdotados: una capacidad intelectual superior. La Estación: revista de la asociación española para superdotados y con talento. 9 (12) 12-23.

Serra-Grabulosa, JM., Pérez-Pàmies, AA.,  Lachica, J., Membrives, S. (2010) Bases neurales del procesamiento numérico y del cálculo. Rev Neurol 50 (1): 39-46.

Solomon, J. (2007) Metaphors at work: identify and meaning in professional life. Fetzer Institute. USA.

Stanovich, KE. (2009) Rational and Irrational thought: The thinking that IQ tests miss. Scientific American Mind. 20 (8) 34-39.

Tubino, M. (2004) Plasticidad y evolución: papel de la interacción cerebro-entorno. Revista de estudios lingüisticos y literarios. 2 (1) 43-59.

Valadez Sierra, MD., Betancourt Morejón, J. y Zavala Berbena, MA. (2006) Alumnos superdotados y talentosos: identificación, evaluación e intervención, una perspectiva para docentes. Manual Moderno. México.

VanTassel-Baska, J.,  Xuemei Feng, A., Brown, E., Bracken, B.,  Stambaugh, T.,  French, H., McGowan, S., Worley, B.,  Quek, C. and Bai. W. (2008) A Study of Differentiated Instructional Change Over 3 Years. Gifted Child Quarterly 52 (4) 297-312.

Willard-Holt, C. (2008) You Could Be Doing Brain Surgery: Gifted Girls Becoming Teachers. Gifted Child Quarterly.  52 (4) 313-325.

Winner, E. (1998) Uncommon Talents: Gifted Children, Prodigies and Savants. Scientific American Presents. 32-37.

Zehhausern, T. R. (1982) Education and the Left Hemisphere, en Student Learning Style and Brain Behavior: Programs, Instrumentation, Research. Reston, NASSP. Virginia.

How does our brain learn?

This was written with special dedication to Valeria Galván Celis

Everything is in our brain, when I say everything I mean EVERYTHING! From our dreams, our talent, our future, our ideas, our perception of love and pain, and the way we learn. The Brain is the only one item shared by any human being on this planet, no matter the color of our skin, socio-economic condition, culture or age.

The way we walk, understand the world, write, how we learn, our perception of life is regulated by infinite processes based on electric and chemical impulses, effect of proteins, hormones and genes.

While some researches are focus on cure and prevent brain diseases like Parkinson, Alzheimer or understanding the neurodevelopment process, some others are searching how to build a brain, for example the Human Brain Project and the Blue Brain Project leaded by Henry Markham, professor of Neuroscience, whose laboratory is located in the Swiss Federal Institute of Lausanne, who will spend one billion Euros trying to unlock the secrets of consciousness, by using data to trace electronic signals between the neurons (Honigsbaum, 2013).

One of the many goals is using all this knowledge about the brain into schools, creating programs based on brain to help children with or without disabilities to learn better, faster and more effectively. Many authors believe that is possible to “teach” our brain to respond in a particular way, and of course, science fiction has ignited this idea and we can learn everything with a click and finish with the huge differences between gift and mental retarded children.

For good or bad, things are not so easy. Our brain learns in an unknown way. Why can some children understand numbers or science?, why are some children wonderful singers?, what is the difference among talent and passion for learning?

These questions began to bother me some years ago, when I saw children with disabilities. Brain scans showed a perfect brain, but these kids were not capable to speak or follow simple orders. If they have a perfect brain, was there another factor?, where was the problem?

As neuroscientist, I began studying brains; I was capable to explain specific structures related with a particular process (Dzib Goodin, 2013a), if a teacher asks me why a child cannot read, I can explain the process that the brain needs to focus on something so complex, but I could not explain why a specific child does not read.

After some frustrations, my position changed, the brain was the receptor of the stimuli in the environment, all information comes from outside our brain, so what are we putting in it?. The question was not how do we learn? But how did learning process arrived to our brains? (Dzib Goodin, 2013b).

This question takes us to a long and challenged road called evolution. Our brains are the current version of natural prototypes. More time we spend on this planet, new needs must be solved; for example to read these lines, you need eyes and ears.

Reading process is a combination of a sound (identification of sounds of alphabet) and pictures (every letter has a different shape, let’s think that most of alphabets have capital and lowercase letters).

Auditory system is a combination of mechanic and neural impulses; our current prototype has needed to design a perfect relationship between tiny bones and hair cells capable to send information to a nerve and then the brain. We have learned to distinguish between sounds in the environment, music, and language, but not only that, we are efficient to determinate the place of the object of emission, intensity and decide if it's a dangerous/friendly sound. Why? because as specie during long time  humans tried to survive from predators.

Image from: Chitka, L., Brockman, A (2005) Perception Space - The final Frontier. Plos Biology. Available at: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0030137

Let’s think for a second, hearing sounds is not enough to survive in the middle of the night with all kind of hunger creatures, we needed eyes. Let’s keep on mind that during many years we were not humans, we were in the ocean, with not enough light to see, so that eye began needing only systems to see in the dark, and we still need them, or we couldn’t see during the night, those cells are called rods.

Eventually, those primitive eyes had to adapt to light, so those eyes needed new cells, we began to see light, that eye began to see colors, and we needed so much that currently we can see colors between 400 to 650 nanometers and that amazing difference needed maybe few hundred thousands years (Nilsson and Pelger, 1994). Inhuman specie’s case, when the fire was discovered, we had to adapt to a wider range of colors, we add yellow and red to our palette, and this means we were capable to distinguish green fruits to mature fruits.

These two systems, hearing and sight, learned to work together, so when we hear a noise our eyes search that noise…but that’s not all!, we needed a neck to support that movement. Movement is another amazing complex process, because species had to move to survive, some mammals like chipmunks or rabbits have to move fast to avoid to be someone’s dinner, but humans had to move to find a better place to live, find food and care babies. Let's add to all those skills the need of moving  our eyes to focus on an objects.

One more step was necessary to be able to read, maybe I should say another BIG step: after creating a language, based on sounds, we had to learn to recognize those sounds, just like a baby does it, and after that, humans create alphabets, this means we could seethose sounds. That coordination between learning the sounds and see them, is not natural to our brain, because this is a new skill to our specie, and even though it has existed since thousands of years, not all persons had access to reading and writing, this has been a recent addition to our neo cortex. This is the reason many persons, even in college have problems with spelling. Who doesn’t have a spelling mistake now and then? This is because we must coordinate two systems, we write as we hear, but words not always can be written following the sound.

Of course learning process is amazingly complex. I am sure Henry Markham will spend more than a decade trying to build a brain, if we think that nature has needed thousands of years, maybe millions, 10 years is a very optimistic agenda, specially with a system than never stop adapting to new environments. 45 years ago only few had access to computers, and we continue adding features, every 2 or 3 years another update surprises us. Nature has much more updates, now we can walk on a crowdie street, avoiding cars and other persons and check Facebook at the same time. Some of us won’t create a coordinated system fast enough, and others continue trying.

Can we teach to our brains? I don’t think so, I wouldn’t spend time or money in that direction, we must enrich our environments to create new skills, because at the end, our brain was designed to answer to the environment and adapt, creating new and more sophisticated strategies, like the simple act of reading.

References:

Blue Brain Project EPFL. Available at: http://bluebrain.epfl.ch/

Dzib Goodin, A. (2013a) La arquitectura cerebral como responsible del proceso de aprendizaje.  Revista Mexicana de Neurociencia. 14(2): 81-85.

Dzib Goodin, A.  (2013b) La evolución del aprendizaje: más allás de las redes neuronales. Revista Chilena de Neuropsicología. 8(1): 20-25.

Honisgbaum, M. (2013) Human Brain Project: Henry Markram plans to spend €1bn building a perfect model of the human brain.

Human Brain Project. Available at: https://www.humanbrainproject.eu/

Lamb, TD. (2011) Evolution of eye. Scientific American. Available at: http://www.scientificamerican.com/article/evolution-of-the-eye/

Masaki, T., and Shigeru, K. (2010) History of studies on mammalian middle ear evolution: A comparative morphological and developmental biology perspective. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution. 314b(6): 417-433.

Mallo, M. (2001) Formation of the middle ear: Recent progress on the developmental and molecular mechanisms. Developmental Biology. 213(2) 410-419.

Nilsson DE., Pelger, S. (1994) A pessimistic estimate of the time required for an eye to evolve. Proceedings of the Royal Society Biological Science .256(1345)53-58.

Adult brain and neuro-plasticity

As I have been sharing in other posts, plastic capacity of young brains has been tirelessly studied, but what does happen with the neuroplasticity of the adult brain?, are brain structures modifiable?. 

 It is known that there are critical periods which depend on the explosion of neural connections and they decay during lifetime, however, new research show a different vision, and now is said that is never too late to make a brain learn new tricks. 

   

  For example, according to preliminary studies in the laboratory of Michael Merzenich of the University of California at San Francisco, who is a pioneer in the understanding of plasticity, memory in pre senile individuals can, with the help of training, be dramatically rejuvenated, and his studies show that plasticity has no limits. Some times even if areas of the cortex, e.g. Broca's area are destroyed by a stroke, a brain attack or a brain tumor, patient is likely to recover function once moved the circuit affected by others who may have other capabilities (Shreeve2005).

Something remarkable both neurogenesis, synaptogenesis is the direct relationship between increased mental activity and physical exercise, which suggests that people could reduce the risk of neural diseases and thereby help to repair brain processes choosing mental challenges and a physically active life, that’s the reason a majority of researches are running environmental stimulation as an important part of the recovering process, demonstrating that the environment can affect on the brain structure, which opens up the possibility a complete new field on areas as architectural designs which could modify the way they build  homes, offices and schools in order to allow more enriched environments that seek better cognitive functioning.

But what about brains who suffers an injury?, current research indicates that plasticity exists, during the pre and post natal, recognizing the existence of critical periods to make this happens, however, once the synaptic connections are established and they break or deteriorate, the pattern of cortical reorganization  the functional recovery of different capabilities is not the same, while the basic mechanisms of plasticity are shared by all the cortex.

However, there are peculiarities in the patterns of recovery depending on the type of injury, mainly finding the following modalities: linguistic and sensory motor, neuropsychological injuries

Regarding the recovery of a motor injury, it is known that  structures of the cerebral cortex is constantly changing in response to training, or behavioral and motor acquisitions. It is thus that the construction of functional maps of motor areas that have been made possible thanks to the use of three neuroimaging techniques: Transcranial magnetic stimulation: which is one way not-invasive stimulation of the cerebral cortex, it’s one of the latest tools that have built-in neuroscience, both for purposes of study and research; functional magnetic resonance imaging: which are a type of magnetic resonance imaging in which the response is measured hemodynamics (blood flow) related to the neural activity in the brain or spinal cord; also we can find the Positron Emission Tomography: which is a technique used on nuclear medicine that produces a three-dimensional image of the body's functional processes,  these techniques that have made possible the understanding of the way in which the motor cortex adapts and changes in response to injury and therapeutic intervention.

Studies conducted in people with central hemiplegia, show that functional recovery through rehabilitation, produces mechanisms of plasticity that differ depending on the timing of the injury.

When the injury requires a longer recovery time and therefore more long-term treatment, permanent changes in the cerebral cortex are generated. In most of the cases new motor routes are created starting  at the motor cortex in the healthy hemisphere and are directed in a ipsilateral manner (contrary), in a way that takes place the functional recovery of the affected side. While in other less numerous group of patients, new axons from the motor cortex not damaged are wrongly projected bilaterally, producing a less functional recovery with intense movements in mirror, this is an example of wrong adaptive plasticity where the patient moves the left hand, at the same time that moves right hand (Diaz-Arribas, Pardo-Hervas, Tabares-washing, Rios-lago and Maestu, 2006) . 

Talking about linguistic recovery, neurobiological studies provide data corresponding to language and its configuration in a certain moment of neurodevelopmental, have allowed increasingly better understand the role of language and their behavior after injury.

In this sense it is known that children around 4 years old have very well located the representation of language in the left hemisphere, in the majority of cases, virtually unchanged in the adult. However, these studies have found evidence that brain cortex involved in linguistic functions is also sensitive to the experience, so the centers related to the language processes  are not stable over time, and expand or contract depending on the experience, since new words are learned or  we stop employ others throughout our life.

Apparently, this area is initially broader throughout the perisylvian areas, which are focusing as it reaches the competence in the language, on the basis of increased complexity and level of specialization, in such a way that the peripheral areas which originally related to the language retains this ability as a secondary capability latent, capable of supplementing or completing the linguistic function in case of injury of the primary area (Hernandez-Muela, Mules, and Mattos, 2004).

However, it is worth mentioning that lesions of the left hemisphere are associated with greater involvement of the normal activity of the right hemisphere and an atypical asymmetry in activations of the perisylvian during linguistic activities area, to a greater extent when the injury takes place in early stages, that when it happens at later stages in life (Gage, 2007).

In this way, as a result of brain plasticity that happens after injury occurred in early stages, diverse studies have been found an increase in the prefrontal, frontoparietal and lower bottom regions activation, for expressive language, and inferior temporal, temporary front and temporary regions for the receptive language. Probably, because these structures are related with the area responsible for functions associated to the language in early stages, that with the maturing and growing complexity of the neural connections, so these are free depending on the type of tasks, but retain this ability, latent form to resume its function in case of later injury (Gollin, 1981; Maciques, 2004; Tubino, 2004; Ginarte, 2007).

In this sense, an early lesion that took place before the first year of life, leads to an extensive reorganization both of the right and left hemisphere, this is known as adaptive plasticity, as occurs in the motor cortex, but there is evidence of plasticity in the regions responsible for the language after a neurological damage, may be different in the case of the motor domain (Diaz-Arribas, Pardo-Hervas, Tabares-Lavado, Rios-Lago and Maestú, 2006).

However, the plastic changes are not limited only to the motor cortex or the language, but it also occurs in sensory systems. In this regard, an example is the case of hearing, which requires connection with environmental sounds as stimuli and whose processing is important for verbal communication, so it is a decisive step for the acquisition of language. This sensory modality is known that there is an auditory critical period for language acquisition. So was demonstrated in studies conducted in deaf children after application of cochlear implants (Hernandez-muela, mules and Mattos, 2004).

  In this regard, in terms of language difficulties secondary to the existence of a sensory deficit by hearing loss, it is necessary to consider two situations: the first one, is when hearing loss takes place prior to the acquisition of language, in the very early stages, while a second situation occurs when the loss hearing occurs subsequent to the acquisition of the language.

     In the first case, the plasticity will be through a migration of the function, while in the second case, the potentiation will be to more long term and will require the support of cochlear implant (Coplan, 1985; Hernandez-Muela, Mules and Mattos, 2004).

The other sensory aspect to consider is the visual capacity, even tought plasticity of visual fields is not well known, it’s possible to talk about at least two situations, on the one hand, when the visual cortex is damaged by a traumatic injury, and when, despite the strength of the occipital cortex, or if by peripheral reasons, it is not possible to develop the vision.

With respect to the first situation, some descriptive studies show the transfer of function from the visual cortex to adjacent areas on the occipital cortex, such as posterior regions of the parietal and temporal lobes, similar to the hearing process, which is called plasticity by migration (Castroviejo, 1996; Deacon, 2000; Ginarte, 2007).

Talking about the second situation, which presents peripheral blindness, caused by tumors in the optic chiasm for example, may be determinants of blindness at very early stages, it has shown the existence of the so-called mode cross plasticity i.e. Permanent reorganization that allows in principle do not own capabilities to a certain area, which appears to increase or facilitate compensatory alternative perceptions of deficit sensory. These changes involve mechanisms neuroplasticos in which areas that processed certain information, accept, process, and respond to other types of information from different sensory modality (Hernandez-Muela, Mules, and Mattos, 2004;Ginarte, 2007).

This way is usually explained the process of plasticity of occipital cortex from blind children ocurred at early stages, which facilitates and at the same time is result of the learning to read Braille, which creating occipital cortex networks ranging from motor areas that allow the movement of the fingers on the paper, and the areas that usually is used for viewing the letters in compensation by the absence of vision. This widening of the cortical representation of the index finger may be due to two mechanisms: the first, by unmasking of silent connections (increase of synaptic efficacy), in the same area injured or deficient and adjacent, and the second, structural plasticity, while other studies have shown the expansion, in the cortex somatosensory representation of the finger index, fundamental Braille readingwith what it says is that people can "see" through their fingers, as they achieve recognition of shapes and even colors at the touch of a surface (Poch, 2001).

References:

Díaz-Arribas, M., Pardo-Hervás, P., Tabares-Lavado, M., Ríos-Lago, M. y Maestú, F. (2006) Plasticidad del sistema nervioso central y estrategias de tratamiento para la reprogramación sensoriomotora: comparación de dos casos de accidente cerebrovascular isquémico en el territorio de la arteria cerebral media. Rev Neurol. 42 (3): 153-158

Hernández-Muela, S., Mulas, F. y  Mattos, L. (2004) Plasticidad neuronal funcional Rev Neurol. 38 (Supl 1): S58-S68.

Gage, F. (2007) Brain, repairs yourself. In Floyd E, Bloom (2007) The best of the brain from Scientific American: mind, matter, and tomorrow’s brain. Washington DC. Dana Press.

Ginarte, Y. (2007) La neuroplasticidad como base biológica de la rehabilitación cognitiva. Geroinfo. Vol. 2. No. 1. 31-38

Gollin. E. S. (1981) Developmental and plasticity: behavioral and biological aspects of variation in developmental. New York. Academic Press.

Maciques (2004)  Plasticidad Neuronal. Revista de neurología. 2 (3) 13-17.

Poch, M.L. (2001) Neurobiología del desarrollo temprano. Contextos educativos. 4. 79-94.

Shreeve, J. (2005) Cornina’s brain: all she is… is here. National Geographic. Vol. 207. num. 3.  6-12.

Tubino, M. (2004) Plasticidad y evolución: papel de la interacción cerebro – entorno. Revista de estudios neurolingüsticos. Vol. 2, número 1. 21-39.