Brain Plasticity - SIVYER'S PSYCHOLOGY (2023)

“Neuroplasticity refers to the physiological changes in the brain that occur as a result of our interactions with the environment. From the time the brain begins to develop in the womb until the day we die, the connections between our brain cells reorganize in response to our changing needs. This dynamic process allows us to learn and adapt to different experiences.”

—Celeste Campbell (undated).

WHY ARE HUMAN CHILDREN BORN EARLIER?

Humans are not very different from kangaroos because, like them, we are naturally selected to give birth prematurely. The human brain is not a complete organ from birth. In fact, by one estimate, a human fetus would need to go through a gestation period of eighteen to twenty-one months instead of the usual nine to be born at a stage of neurological and cognitive development comparable to that of chimpanzees. The human brain takes at least twelve years to develop extensively and twenty to twenty-five years to fully develop.

THEORY ONE

The traditional explanation for the nine-month gestation period and newborn impotence is that natural selection favored birth earlier in fetal development to accommodate brain size for the narrower hips resulting from bipedalism.

THE SECOND THEORY

The second theory suggests that the metabolic needs of the human fetus may exceed the mother's ability to meet her baby's energy needs and her own, takes into account how much food the baby needs at nine months of gestation and remembers the ancestral environment hostile from which man it arose. As a result, the mothers may have had to give birth early to avoid starvation,

THIRD THEORY

The third theory suggests that humans are born with empty brains, because this allows the nervous system to escape the limitations of its own genome and adapt to all the environments and situations a person might encounter, such as living in the Arctic and eating mainly meat. for example, to live in the desert and be a vegetarian. Other animals have less need for such plasticity because they have evolved to thrive in only one type of environment. For example, a rhino cannot thrive anywhere other than a hot, dry environment because its brain is immobilized from birth and cannot learn new things. But man can live and adapt to any climate, language, and way of life.

Whatever the cause, human babies are born so early that their brains are less than thirty percent the size of an adult brain, meaning they are premature.

DUTY DEPENDS ON EXPERIENCEALSO KNOWN AS DEVELOPMENTAL PLASTICITY

The plasticity awaiting experience iswhen the brain waits for certain experiences, like seeing a face, before it can connect properly.Plasticity is typified pending experience.through neurogenesis, synaptogenesis, exuberant synaptogenesis, synaptic pruning, neuronal migration, myelination of neurons that are fertile in the first years of life.

The brain is not fully mature at birth, which may be because humans required the brain to develop in culturally specific ways in order to successfully navigate the environment. In the early years, the brain makes many connections and pathways. The repetition of an action or experience helps to forge these pathways in the brain. When properly reinforced, they become durable.

Plasticity awaiting experience.It refers to the integration of specific environmental stimuli into normal patterns of development. Certain environmental exposures are necessary during limited, critical, or sensitive periods of a child's development and are essential for healthy maturation. For example, finches need to hear adult songs before puberty to learn to sing at a species-appropriate level of complexity. Human beings must experience hearing a language or seeing a face at critical stages in the development of their cerebral cortex. If they are not given the proper stimuli, this area can be removed after the first six months of life.

In short, experience-awaiting plasticity is the pervasive development of neural connections that occurs as a result of common action.experienceto which every human being is exposed in a normal environment. The human brain is thought to have evolved early in life with an innate desire to connect certain sensory experiences: for example, faces for facial recognition, visuospatial information for navigation; especially voices for language learning,

CRITICAL PERIODS

The plasticity that awaits experience is related to the concept of critical period.

Thus, proper brain development depends on exposure to expected sensory experiences, such as hearing language and seeing faces, as these sensory stimuli are essential for the formation of neural connections in the areas of speech and facial recognition. Skills that have a critical period are functions that the brain can expect, such as visuospatial awareness. Establishing connections and pathways in these areas is crucial as it allows a person to see, hear, smell, learn and reason. For example inbirthalthough there are basic circuits related to vision, the circuits are rudimentary, like this:niñoTheir eyesight is quite blurry: they can recognize light, shapes, and movement.you can seeonly about twenty or fifteen inches away. Your baby's vision will continue to develop from early visual experiences gained at certain points in her development, such as what she visualizes in the weeks after birth.

Different circuits come together at different times during infancy: smiling occurs around six weeks, walking between ten and twelve months, object permanence around nine months.

RESEARCH SUPPORT

DESTROYED ENVIRONMENT

The critical window and pruning are supported by experiments; For example, raising animals in poor environments hinders development and can lead to a permanent loss of function. Monkeys, cats, and rats reared under light conditions but without pattern visual stimuli show poor visual guidance of behavior, even after long periods of recovery from pattern visual stimuli. Reduced vision is associated with reduced dendritic branching.

A visual deprivation study in cats in which one eye of newborn kittens was closed for three months (Wiesel and Hubel, 1965). After this time, the researchers examined the connections between both eyes ("open" and "closed") and the brain and discovered that there was a severe deterioration in the neural connections in the visual areas of the brain due to the lack of ocular stimulation. . closed eye. As a result, the brain adapted to receive information only from the open eye and remained blind to the other eye (Blakemore and Frith, 2000). When adult cats were subjected to a similar period of blindness in one eye, there was no deterioration in neural connections because as kittens both eyes were wired for vision. The conclusion was that the visual system requires sensory stimuli during a critical period of development (usually in the first months of life) to "lock on" to the perception of the environment.

Explicitly comparing cats to humans isn't always helpful, as their visual systems have evolved in response to various selection pressures, so cats don't recognize faces and can't see colors, but they do have better peripheral vision than cats. humans, for example. However, cases of blind people who regain their sight in adulthood show that they are always blind in the face. Others have less severe symptoms and early vision deprivation may have trouble distinguishing between male and female faces or be unable to decipher emotions from facial expressions.

PARENT-SON RELATIONSHIP

New synaptic connections and the maintenance of existing connections are established in response to social experiences. This means that infant brain development depends on important forms of sensory and motor stimulation by caregivers. This stimulation includes emotional interactions with sensitive caregivers.

Three discoveries in the neurobiology of child development are relevant to plasticity:

• Particular sensitivity of brain development to supportive experiences with people.

• The dependence of the developing brain on social and emotional stimuli to establish and maintain synaptic connections.

• "Conditioning" of the brain by experiences in the care relationship with caregivers, especially in relation to the stress response.

The high-energy impulses of brain growth in early infancy are integrated and regulated by the emotional exchange between infants and their caregivers (Siegel, 2001). Siegel argues that there is great agreement across many fields of research across disciplines, both in animal and human studies, pointing to the fundamental importance of emotional communication for brain development.

This early brain development can be stunted or distorted by a lack of experience-dependent neurochemical signals when expected experiences do not occur, such as in an emotionally deficient parenting environment. They can also be damaged by wrong signals, such as abuse. In the latter case, brain development is influenced by the presence of large amounts of the hormone cortisol, which is produced by the hypothalamic-pituitary-adrenal system during long periods of stress.

As examples of evidence supporting these claims, Greenough and Black (1992) found that dendrite growth in young rats is dependent on specific forms of tactile and emotional stimulation during lactation. In infants, interpersonal encounters that involve looking at each other begin to peak around 2 months of age. They are associated with dramatic metabolic changes in the primary visual cortex, during which the infant's visual experience modifies synaptic connections in the occipital cortex (Katz, 1999).

Studies with rats have found that early experiences in mother-pup interactions permanently alter the rat's brain's reactivity to stress. The mother's regular, daily separation from the pups interferes with her protective behavior. This causes long-term changes in their puppies' behavioral and hormonal responses to stress. Conversely, manipulations and tactile stimulation associated with the comforting experiences that the mother rat provides to her offspring induce persistent changes in stress hormones in the hypothalamus (Schore, 2001a). Rat pups exposed to such favorable rearing conditions are less anxious and fearful, and less responsive to future stress.

If the results of these animal studies can be extrapolated to human babies, and are considered important by many who work in this field, it must be said that the emotional and social characteristics of early experiences are important because they have lasting effects on the body. human. . child's brain The effects occur either through experiences that comply or not with experience-dependent development and use of the brain and its neural connections, or by conditioning the brain to respond to environmental conditions, especially stress, in a way that strongly programs subsequent behavior. answers. High stress reactivity causes cognitive impairment and high levels of emotionality, which interfere with intellectual and social functioning (Shonkoff & Phillips, 2000).

Young mammals are dependent on their parents and must learn to identify, remember, and prefer their caregivers. Changes in these relationships can significantly alter brain development, leaving effects that persist into adulthood. For example, extensive studies in rats have shown that mother-pup contact time, including the amount of maternal licking and grooming, correlates with various somatic and behavioral differences, and specifically modifies the development of the hypothalamic-pituitary-adrenal axis. These changes correlate with changes in gene expression in the offspring. Other studies have found changes related to mother-infant interactions in mPFC, OFC, hypothalamus, and amygdala.

The effects of reduced parent-child interactions in humans have been studied in institutionally adopted children and have been related to age of adoption. For example, 12- to 14-year-old children who were adopted from foster care with an average age of 12 months had reduced gray matter volume, and especially reduced prefrontal volume, consistent with previous studies showing reduced gray matter thickness. the prefrontal cortex (eg, Hodel et al. 17). Large studies of Romanian orphans adopted in various Western countries have found similar results, although an additional finding is that adoption after approximately 18 months is associated with very poor behavioral and neurological outcomes, even after more than 20 years of living in good families. and stable. These children have smaller than normal brains, limited cognitive and social functions, and abnormal brain electrical activity (eg, Johnson et al.).

LANGUAGE, COGNITIVE EXPERIENCE AND POVERTY

Babies can distinguish the speech sounds of all languages ​​during the first year of life, but the auditory system begins to change in such a way that the baby becomes an expert at discriminating sounds in its linguistic environment, but loses the ability to distinguish sounds. that he does not experience. Learning more than one language in the development process adds another dimension, especially when learning to routinely switch between languages. This mental change has a significant impact on cognitive abilities, especially in the improvement of attention and executive functions and the increase in cognitive reserve in the aging process, possibly as a consequence of some type of plastic changes in the frontal lobe.

FACTORS AFFECTING BRAIN PLASTICITY

Although virtually all children learn a language, there are big differences in the rate at which they acquire vocabulary. In a major study, Hart and Risley followed children for two and a half years (7 to 9 to 36 months), observing families at home for one hour per month.11 Children could be classified as having a rich vocabulary at age 3 years (~1200 words) compared to children with less vocabulary (~400–600 words). This difference was related to the number of words the children were exposed to at home, which was directly related to socioeconomic status (SES). Thus, in a year, children with a high socioeconomic level would be exposed to about 11 million words, and children with a low socioeconomic level, to about 3.2 million words. At age 4, the average child with a lower socioeconomic status would be exposed to about 30 million fewer words than a child with a higher socioeconomic status. When the 9- to 10-year-olds were re-measured, the difference related to SES actually increased, suggesting that school had a negligible effect on resolving this deficit.

The difference in cognitive ability associated with SES is related to developmental differences in the cerebral cortex. Noble et al.12 examined the relationship between the NSE and the surface of the cerebral cortex in more than 1,000 participants between 3 and 20 years of age. Lower family income, regardless of ethnicity or gender, was associated with reduced cortical surface area across broad areas of the frontal, temporal, and parietal cortices, which was correlated with poorer performance on tests of attention, memory, vocabulary, and reading. Therefore, a lower SES is associated with less cortical area and worse test scores.

DIET

Most research on nutrients for development has focused on the effects of nutrient deficiencies, particularly those related to energy proteins, iron, zinc, copper, and choline. These nutritional deficiencies can have global effects on the developing brain or specific effects on particular brain circuits, depending on the precise moment in which the nutrient deficiency occurs. A more intriguing question is whether brain plasticity could be enhanced by vitamin and/or mineral supplements, and especially nutrient combinations that would work synergistically to improve metabolic activity and ultimately brain function. One promising product is EmpowerPlus. This product is a blend of 36 vitamins, minerals and antioxidants and includes a proprietary blend of herbal supplements such as ginkgo biloba and the neurotransmitter amino acid precursors choline, phenylalanine, glutamine and methionine. This product has been reported to improve mood and behavior in children and has been shown to reduce anger, activity levels, and social withdrawal in autistic individuals while increasing spontaneity. Rodent studies have shown that the use of this supplement during development leads to improved motor and cognitive functions and an increase in the dendritic tree in the mPFC. The mechanism of influence of diet on the structure of neurons may be epigenetic. Domínguez-Salaz et al25 studied the methylation of genes in the blood of babies conceived during the dry and wet seasons in The Gambia. Maternal diets vary greatly between seasons, as does the pattern of gene methylation.

GUT BACTERIA

Given the interaction of the microbiome with the brain, Dinan et al26 proposed that the use of bacteria to alter the microbiome could represent a new class of psychotropic drugs, called psychobiotics. The idea is that manipulation of bacteria in the gut can modify brain plasticity, supported by several studies showing that normal gut microbiota can influence brain and behavioral development. For example, manipulation of gut bacteria in newborn mice had an effect on anxiety and motor behaviors. These behavioral changes were correlated with changes in striatal norepinephrine, dopamine, and serotonin turnover, as well as changes in striatal synapse-related protein production. cortex and striatum.

IMMUNE SYSTEM

Many immune system proteins are expressed in the developing brain and some appear to be essential for synapse development and modification. Although there is little direct evidence that the immune system can interfere with brain development and plasticity, epidemiological evidence indicates that maternal infection is a risk factor for various neurodevelopmental disorders, including autism, neurodeficit disorder, attention hyperactivity disorder and schizophrenia.

OTHERS A03:

There's been a lot of hype about how malleability can enable anyone to learn anything, regardless of age or past educational deficits, but it's just experiential learning, not expectant learning. This means that policymakers need to ensure that children from poor backgrounds receive very early intervention in care and education, as investing in social care or education after 6 or 2 years will be too late to correct inequities.

The more resilient types of learning often seen in adults are theorized to be the resultEXPERIENCE THE OUTSTANDING FLEXIBILITYfor example, faces, learning languages ​​to categorize (first diagram template), number sense, timing, deceit, social relationships, and a positive self-schema—things the brain needs to function normally, regardless of its location.

CONCLUSIONS

The developing brain responds to a wide variety of factors that modulate its development, ranging from parental experiences before conception, pregnancy experiences, and postnatal experiences. We view these factors as single, independent events, but as we move through life, experiences interact to change both behavior and the brain, a process often referred to as metaplasticity. We are just beginning to understand how different factors can interact or how the effects of negative factors like severe stress can be mitigated through experiences like tactile stimulation. We focus here on changes in behavior, neuronal morphology, and epigenetics, but we certainly realize that plastic changes in brain organization can be studied at many other levels, both in humans and in laboratory animals. Finally, in our discussion we gave equal weight to each of the factors, but it is likely that there are significant differences in the magnitude of the effects. The effects of early stress and psychoactive drugs are the best studied and probably the strongest negative effects. On the other hand, early experiences such as tactile stimulation appear to be highly influential and have the ability to reverse some of the negative effects of stress and perhaps psychoactive drugs.

STRUCTURAL DUTY

NEUROPLASTICITY: EXPERIENCE-DEPENDENT PLASTICITY, ALSO KNOWN AS STRUCTURAL PLASTICITY (OPERATIONAL AND CLASSICAL CONDITIONING COVERED HERE)

The critical window used to be the basis for the belief that an old brain cannot acquire a new skill without much difficulty. The hypothesis that behaviors are acquired during a critical period was first proposed by neuroscientists Wilder Penfield and Lamar Roberts in 1959, and popularized by linguist Eric H. Lenneberg in 1967. Lenneberg favored the evidence-based hypothesis that behaviors are acquired during a critical period. Children who experience brain damage early in life develop significantly better language skills than adults with similar injuries.

However, it is now believed that the reason why some types of learning are more resistant to plasticity in older people and others are not, is due to the way in whichnecessaryskills for human development. Human brains have not evolved to display many of the skills required in modern life; many of them are culturally significant, such as driving, writing, algebra, cooking, geography, etc. Humans are adaptable beings, they can live anywhere and have the potential to speak any language or learn a new skill. So it makes sense that the brain is capable of learning new things throughout its life.

DUTY DEPENDS ON EXPERIENCE

Experience-dependent plasticity is also known as activity-dependent learning and structural plasticity.

Flexibility depends on experience.the plasticity of learning and remembering that occurs throughout life.

Specifically, it isa form of functional and structural neuroplasticity that results from the use of cognition in response to personal experiences. Human beings must constantly learn throughout their lives, and structural plasticity allows the human brain to adapt through learning, operationally, classically, or through imitation. This allows people to gain specific knowledge in many areas, eg education, geographical knowledge, languages, driving license, cooking, etc.

Flexibility depends on experience.the biological basis for learning and creating new memories.

PROHIBITED

It used to be believed that adult brain networks repair themselves after a certain age and that "old dogs can't learn new tricks." However, over the last twenty years, a great deal of research has revealed that the brain never stops changing, learning, and adapting to experiences. This type of brain change is called experience-dependent plasticity. In short, it refers to most of the skills and knowledge acquired throughout life. It is called experience-dependent because the brain does not necessarily expect to learn what is presented to it, like an Inuit child learning to build an igloo). These skills are likely to be acquired through instrumental, classical, and observational learning, and help formulate schemas and semantic knowledge. There is no critical period for experiential learning, for example, you can learn to drive at 16, 30 or 50 years old. Perhaps that is why it seemed that some older people learned certain skills very easily, even if they had not had contact with them in childhood. All education is based on a plasticity dependent on experience.

The brain's ability to change in the process of learning and remembering new knowledge is essential for survival, as humans must constantly learn new things in order to effectively navigate their environment. The brain's ability to reorganize neural pathways throughout life as a result of experience. Simply put, it refers to the brain's ability to change as it learns.

In the case of EXPERIENCE-DEPENDENT PLASTICITY, a change occurs in the internal structure of neurons, in particular, the number of synapses increases and dendrites and axons grow profusely.

EVIDENCE

Numerous studies have confirmed that the adult brain retains a certain degree of "plasticity," that is, that its structure and organization can physically change as a result of new demands placed on it, and that these changes can occur in adulthood and not they are limited to the period of infant development. One of these studies compared structural MRIs of the brains of London taxi drivers with a control group that did not drive taxis (Maguireme in, 2000). It was found that "the posterior hippocampus of the taxi drivers was significantly larger compared to that of the controls, and that the volume of the hippocampus correlated with the amount of time spent as a taxi driver."

CLASSIFICATION:

Maguire's study has many positive aspects; it is applicable in the real world and the control group allows comparison. However, the study is beta-laden and doesn't really tell us about the plasticity of women's brains because the samples were from men. Perhaps the posterior hippocampus is more susceptible to plasticity in males due to the effects of testosterone on visuospatial memory, which is more common in males. Furthermore, taxi drivers cannot be generalized to the entire population, as they have acquired a high degree of specialized knowledge over a long period of time.

However, research has also shown that unskilled people can learn new skills very quickly and that physical evidence of this malleability appears very quickly. One study took a group of non-musicians and instructed them to practice a series of five-finger piano exercises for two hours a day for five days. At the end of five days, the part of the brain responsible for finger movements was found to be enlarged and more active compared to a non-exercising control group (Pascual-Leoneme in, 1995).

Other studies of adult learning have focused on women and other types of learners. For example, work with musicians demonstrated that the portion of the auditory cortex in expert musicians was up to 25% larger than in nonmusical controls, and that the degree of comparative magnification correlated with the age at which musicians began to practice (Pantevme in, 1998).

The Pantev results indicate that there is also a natural decline in cognitive functioning with age.

One of the most popular theories to explain the decline in learning ability in older brains is related to synaptogenesis. Research shows that the younger a person is, the more fertile and faster are their neural connections. In fact, this is called synaptogenesis in infancy.exuberant synaptogenesisfor your productivity. As the brain ages, synaptogenesis occurs at a slower rate and frequency; This may explain why older people seem to learn some tasks more slowly.

There are other theories about the cognitive decline of the brain in the elderly. For example, one theory suggests that older people can process and retrieve information and knowledge at a slower rate because they have too many neural connections, which greatly slows down the speed of information processing and learning. In fact, researchers at the University of Tübingen (Germany) believe that the human brain works more slowly in old age because it has to process information from a lifetime to remember simple facts (hence more connections). They say their research, rather than being weak, shows that older brains are actually more powerful. Perhaps the cognitive decline is more related to a slowdown in synaptic pruning.

However, there are studies that show that the brain continues to learn well into old age. Boyke et al. (2008) found evidence of brain plasticity in participants in their 60s who were taught a new skill: juggling. They found an increase in the amount of gray matter in the visual cortex, although these changes reversed upon cessation of exercise.

Imaging studies (eg, fMRI, PET, MEG) of the developing human brain have confirmed that growth and development continue into early adulthood. However, some areas seem less resistant to change. For example, learning music in terms of temporal patterns must be done early in development, but the perception and repetition of sounds can be learned at any age.

“In the brains of nine string musicians examined by MRI, the amount of somatosensory cortex dedicated to the thumb and fifth finger of the left hand (the fingers that touch fingers) was significantly greater than in non-musicians. The duration of the players' daily practice had no effect on the cortical map. But... the younger the child picked up the instrument, the more the cerebral cortex was dedicated to the game. Newsweek, February 19, 1966

The Critical Period is the concept of a window of opportunity that opens in early childhood and then closes and never reopens, which was the basis for the belief that the older brain is incapable of acquiring any new skills without much difficulty.

The hypothesis that behaviors are acquired during a critical period was first proposed by neuroscientists Wilder Penfield and Lamar Roberts in 1959, and popularized by linguist Eric H. Lenneberg in 1967. Lenneberg favored the evidence-based hypothesis that behaviors are acquired during a critical period. Children who experience brain damage early in life develop significantly better language skills than adults with similar injuries.

The reason why some types of learning are more resistant to plasticity in older people, but others may not be related to hownecessaryskills for human development. Human brains have not evolved to display many of the skills required in modern life, many of which are culturally significant, such as driving, writing, algebra, cooking, geography, etc. The more resilient types of learning often seen in adults are theorized to be the resultEXPERIENCE THE OUTSTANDING FLEXIBILITY

EXPERIENCE THE OUTSTANDING FLEXIBILITYrefers to a finite period in which the body has a greater sensitivity to external stimuli than is necessary for the development of a specific skill. • For example: some areas of the visual cortex are only capable of forming synapses in the early stages of development. Individuals MUST BE EXPOSED to external visual images; otherwise, the synapses cannot connect and form pathways representing, for example, visual memories, spatial awareness, and facial recognition. When these abilities develop, they usually involve specific areas of the brain.

It is believed that the human brain evolved under the pressure of natural selection and acquired certain abilities: basic vision, first language learning, categorization, number sense, time sense, deception, social relationships.

Once the critical period has passed, if the person has not been exposed to the necessary visual stimuli, they will experience some damage to their eyesight. If they are absent, brain development is abnormal and critical period effects may occur. The development of the brain depends on exposure to the correct concepts, that is, the stimuli necessary to acquire these skills are what the brain can expect.

Other supporting evidence:

Playing video games

Playing video games involves many complex cognitive and motor demands. Kuhn et al. (2014) compared a control group with a video game training group that trained Super Mario for at least 30 minutes a day for 2 months. They found a significant increase in gray matter in several areas of the brain, including the cerebral cortex, hippocampus, and cerebellum. This increase was not pronounced in the control group. The researchers concluded that video game training resulted in new synaptic connections in brain areas involved in spatial navigation, strategic planning, working memory, and fine motor skills—skills that are important for successful gaming.

Meditation

Researchers working with Tibetan monks have been able to show that meditation can change the inner workings of the brain. Davidson et al. (2004) compared 8 Tibetan meditation practitioners with 10 student volunteers who had no prior meditation experience. Both groups were fitted with electrical sensors and asked to meditate briefly. The electrodes detected much higher gamma wave activity (important because they coordinate neural activity) in the monks. The students showed only a slight increase in gamma wave activity during meditation. The researchers concluded that meditation not only changes brain function in the short term, but can also cause lasting changes, based on the fact that the monks even had significantly more gamma wave activity than the control group.beforethey began to meditate

Wider implications for research

The insights gained from plasticity research have many implications for society. Knowing how we learn has applications in educational theory, ie how people learn and why some people may find learning problematic (special needs education). In fact, much research has now been directed at babies "in the hot room" and/or looking at ways to increase synaptogenesis. Initially, it appeared that the principle of creating an enriched environment was confirmed by studies by Kempermann et al. (1998), who studied rats reared in an "enriched" or "private" environment. The "private" environment was a normal laboratory cage for a single rat, while the "enriched" environment included a variety of toys such as wheels and ladders, as well as other pet rats. Rats raised in an "enriched" environment were found to have: up to 25% more synapses per neuron in areas of the brain involved in sensory perception than "deprived" rats, raised alone in a laboratory cage, no "playmates". or toys. Furthermore, rats raised in complex environments perform educational tasks better than rats deprived of this opportunity. (Blakemore and Frith, 2000).

Again, be careful as animal research has some limitations. The obvious point is that animals are not human: they are less flexible in their behavior and lack higher-order human abilities. It is also known that the location of certain processes in the brain of animals differs from that of the human brain (for example, rats and humans seem to use different parts of the brain for working memory) and that the brain matures differently. in different species (analysis of synaptic processes). The density in babies and adults of different species show different patterns of development) (Byrnes and Fox, 1998). All of this means that we must be extremely careful when extrapolating animal studies to possible implications for human learning.

In fact, the OECD report makes it clear that in humans there is no evidence linking synaptic density and higher learning; and there is no evidence linking synaptic density in early life with density later in life. This reasoning has also been criticized because the so-called "enriched" environment of the rats was actually much closer to the normal rat environment, and thus the study showed detrimental effects of an artificially "private" environment.

There is evidence to support the idea that a loving environment has an impact on development. This follows from research on Romanian orphans who grew up in extremely impoverished environments (O'Connorme in, 1999). These children suffered from this deprivation, although it was found that rehabilitation was still possible if it occurred before 6 months of age.

However, extrapolating these findings to the idea that young children should grow up in an enriched environment to increase their learning potential is a bit of a stretch. "Enriched" when applied to early childhood education is very pleasing to the eye of the beholder, and often reflects their cultural and class values ​​(Bruer, 1997), and this preference is definitely not confirmed by neuroscience. The child does not need an enriched academic environment, but rather close contact with her primary caregiver, eg hugs, eye contact, mutual communication, attention, security, and love.

Thus, while research on synaptogenesis has the potential to be used in learning strategies, rat research is now being used importantly to encourage parents and other educators to use programs that facilitate better learning. This is an example of how research results can often be misapplied or used almost fraudulently to extort money from people.

“The idea of ​​playing a game that will make you smarter seems obvious. This is the idea behind a multi-billion dollar industry that sells brain training games and programs designed to improve cognitive abilities. However, a CBC investigationMercadoshows that brain training games like Lumosity may not improve brain performance in everyday life. Zachary Hambrick, a professor of cognitive neuroscience at Michigan State University, says that "companies need to show that gaming makes you better at everyday tasks, not just the games themselves."

FUNCTIONAL BRAIN REGENERATION AFTER TRAUMA

FUNCTIONAL PLASTICITY:

Functional plasticity (also known as adaptive plasticity): Functional plasticity allows our brain to adapt to injury, for example, it refers to the brain's ability to transfer functions from an injured area of ​​the brain to uninjured areas (often in the contralateral side). hemisphere or adjacent areas of the injured area through the growth of dendrites and the redirection of neurons.

PROHIBITED:

"For many decades it was believed that the brain is a non-renewable organ," that the number of brain cells is limited and that they slowly die off as we age, whether we try to conserve them or not. “In adult centers, neural pathways are something permanent, complete and immutable. Everything can die, nothing can regenerate"

— Ramón y Cajal, cited in: Fuchs & Flügge, 2014

Functional plasticity allows the brain to adapt to injury, for example, it refers to the ability of the brain to transfer functions from the damaged area of ​​the brain to uninjured areas (often in the contralateral hemisphere or adjacent areas of the damaged brain, by dendrite growth). , mirror neurons, neuron redirection and unmasking of unused neurons).

In the 1960s, researchers studied cases in which stroke victims were able to regain function. They found that when brain cells are damaged or destroyed, as is the case with a stroke, the brain rewires itself over time so that it can regain a certain level of function. Although parts of the brain can be damaged or even destroyed by trauma, other parts seem to take over lost functions. Neurons located next to damaged areas of the brain can create new circuits that resume some of the lost functions.

Stroke victims = Individual differences A03: Also, in the case of the phantom limb phenomenon, the person still has pain or sensation in the part of the body that has been amputated. This is an extremely common occurrence that occurs in 60-80% of amputees. Explanations for this are based on the concept of neuroplasticity, as the cortical maps of the excised limbs are thought to connect with the surrounding area in the postcentral gyrus. This causes activity in the surrounding cortical area to be misinterpreted as the cortical area previously responsible for the amputated limb. This is another example of functional brain regeneration after injury.

recovery mechanisms

• Neural unmasking: what happens in the brain during recovery? The brain is capable of remodeling and reorganizing itself, creating new synaptic connections near the damaged area. Secondary neural pathways that would not normally be used to perform certain functions are "unmasked" to allow their continued function. This process is supported by a series of structural changes.

• Axon germination: New nerve endings grow and connect to undamaged areas.

• Mother cells.

• Reform of blood vessels.
  Recruitment of homologous (similar) areas in the opposite hemisphere to perform specific tasks, e.g. if Broca's area has been damaged, the area on the right can take over.

unmask neurons

Wall (1977) first identified what he called "latent synapsesin the brain. In short, latent synapses are synaptic connections that exist anatomically, but their function is blocked. Under normal circumstances, these synapses can be ineffective because the intensity of the neural impulses is too low to activate. However, increasing the rate of entry into these synapses, which occurs when the surrounding area of ​​the brain is damaged, can open (or "unmask") these dormant synapses. Unmasking dormant synapses can open up connections to areas of the brain that are not normally activated, creating a lateral spread of activation that gives way to the development of new structures over time.

Human echolocationis an example of how brain damage can be redirected. Human echolocation is the ability of a human being to detect objects in her environment by sensing the echoes of those objects and actively producing sounds; for example, hitting with a stick, tapping with the foot, snapping the fingers or clicking the mouth. Research conducted in 2010 and 2011 using fMRI techniques showed that parts of the brain involved in visual processing are adapted to the new ability of echolocation. The results show that the echoes heard by these patients were processed by the brain areas responsible for seeing, not hearing.

There is evidence in humansLimited to small-scale studies with people who already have problems, it's not clear if what we see is due to recovery or individual differences..

Mother cells They are unspecialized cells that can give rise to different types of cells with different functions, including assuming the characteristics of nerve cells. There are many opinions about how stem cells work to treat brain damage caused by trauma or neurodegenerative diseases. The first view is that stem cells implanted in the brain will directly replace dead or dying cells. The second possibility is that the transplanted stem cells secrete growth factors that somehow "rescue" the damaged cells. A third option is to transplant cells from a neural network that connects the undamaged site of the brain where new stem cells are formed with the damaged area of ​​the brain.

This is confirmed by Tajiri et al. (2013), who provided evidence of the role of stem cells in the recovery process after brain injury. Rats with traumatic brain injury were randomly assigned to one of two groups. One group had stem cells transplanted into an area of ​​the brain affected by trauma. The control group received a brain infusion solution that did not contain stem cells. Three months after brain damage, the rat stem cells showed clear development of neuron-like cells in the area of ​​damage. This was accompanied by a constant flow of stem cells migrating to the site of brain damage. The control group was no different.

There are a number of factors to consider before concluding that functional recovery is possible:

Age differences in return to functional fitnessIt is widely accepted that functional plasticity decreases with age (Huttenlocher, 2002). According to this view, the only option after traumatic brain injury that extends beyond childhood is to develop compensatory behavioral strategies to address the deficit (such as seeking social support or developing coping strategies for cognitive deficits). However, research suggests that even skills that are commonly considered fixed in childhood can be changed in adults through extensive retraining.

Despite these signs of adult plasticity, Elbert et al. (2001) concluded that the reorganization capacity of neurons is much greater in children than in adults, as evidenced by the extensive practice that adults require to induce change. However, there are factors that can increase the probability of functional recovery.

BENEFITS OF NEUROPLASTISM FOR THE BRAIN

• Recovery from brain events such as strokes.

• recovering from brain injuries

• Ability to rewire functions in the brain (for example, if an area that controls one sense is damaged, other areas may be able to recover)

• Loss of function in one area may improve function in other areas (for example, if one sense is lost, others may be heightened)

positive plasticity

Educational Achievement and Return to Functional Fitness:Schneider et al (2014) found that patients with a tertiary equivalent education are seven times more likely than patients who have not completed high school to experience disability one year after moderate or severe brain injury. They conducted a retrospective study based on data from the US Brain Injury Systems Database. Of the 769 patients studied, 214 achieved disability-free recovery (DFR) after one year. Of these, 39.2% of patients with 16 years of education or more achieved DFR, as did 30.8% of patients with 12-15 years of education and only 9.7% of patients. with less than 12 years of education achieved the DFR after only one year. The researchers concluded that "cognitive reserve" (associated with higher levels of education) may be a factor in neural adaptation during recovery from traumatic brain injury.

If one area is badly damaged, it is difficult for the remaining areas to repair the further loss of tissue.

NEGATIVE FORMABILITY:

However, plasticity has its drawbacks. Just as people can develop plasticity to learn new skills, they can also develop plasticity to perpetuate a bad habit or negative emotion. Neurologists divide neuroplasticity into the types that have itpositivelubricantnegativebehavioral consequences. For example, if the body can recover from a stroke, this plasticity can be considered an example of "positive plasticity". Examples of negative plasticity include post-traumatic stress disorder, chronic pain disorders, phantom pain, changes such as excessive levels of neuronal growth leading to spasticity or tonic paralysis, or excessive release of neurotransmitters in response to injury that can kill nerve cells. , or any other place where neural pathway communication techniques have become more effective in eliciting negative reactions.

CHRONIC STRESS:

Constant and prolonged stress that blocks the formation of new neurons and negatively affects the defense mechanisms of the immune system.

COGNITIVE TRAINING:

Brain Fitness Training: A brain fitness course designed to help exercise specific "mental muscles." The underlying principle of cognitive training is to improve "basic" skills such as attention, memory, processing speed, and problem solving.

COGNITIVE RESERVE (THE BRAIN RESERVE):

The theory takes into account the fact that individuals vary greatly in the severity of cognitive aging and clinical dementia. Mental stimulation, education and professional level are believed to be the main active elements in building a cognitive reserve that can help resist bouts of mental illness.

Negative plasticity: video games

A controversial example of negative plasticity can occur with children who often engage in video games and violent actions. Since these games are designed to induce stress, it stands to reason that children who play them might experience decreased empathy or a less regulated stress response. This type of activity can cause negative plasticity in the survival brain's limbic system.

Negative plasticity: adolescent addiction

New research suggests that the extremely malleable and (and therefore highly adaptable) adolescent brain may have a double-edged sword. While radical brain remodeling during adolescence offers tremendous opportunities for growth and learning, it also appears to increase adolescents' vulnerability to the long-term effects of environmental influences such as stress and drug experimentation.

Negative plasticity: adolescent addiction

One of the consistent findings is that adolescents are extremely vulnerable to drug addiction. This fits with the notion that addiction is a form of "overlearning" because the adolescent brain is still rapidly rewiring its circuits and learning faster (which basically means that the adolescent brain is very malleable). As a result, the adolescent brain can become more deeply addicted because behaviors are not just over-learned; almost permanently implanted in the brain.

To test their hypothesis, the researchers gave adolescent and adult rats repeated access to cocaine in a specific environment, essentially teaching the animals to associate that environment with the drug. After each drug exposure, the animals were free to return to the drug-related environment or go elsewhere. In general, adolescent rats showed a greater preference for returning to the area of ​​drug use.

A03: Extrapolation to human problems. People can choose not to use drugs.

WHY IS THE HUMAN BRAIN SO PLASTIC: EVOLUTION?

The third theory suggests that humans are born with empty brains, because this allows the nervous system to escape the limitations of its own genome and adapt to all the environments and situations a person might encounter, such as living in the Arctic and eating mainly meat. for example, to live in the desert and be a vegetarian. Other animals have less need for such plasticity because they have evolved to thrive in only one type of environment. For example, a rhino cannot thrive anywhere other than a hot, dry environment because its brain is immobilized from birth and cannot learn new things. But man can live and adapt to any climate, language, and way of life.

Prevention of Alzheimer's disease and cognitive decline.

When a person acquires a skill (for example, the ability to read), they are actually creating a system in the brain that does not exist or does not exist in a person who does not read. This [ability] actually evolves in the brain.This is because the brain is designed and built to be stimulated and challenged and to carefully explore, analyze and interpret the environment. In the early days of human development, attention to detail was essential for survival. Today, however, people are moving away from the details of life. For example, instead of keeping appointments and to-do lists in their heads, they use electronic reminder devices. Highways and streets are paved and lighted, so getting from one place to another requires virtually no attention. The theory behind cognitive decline is that if a person doesn't challenge their brain enough with surprising new information, it will eventually begin to deteriorate.Cognitive decline can be prevented by challenging the brain: reading, language learning, meditation, etc.

“In general, in your third or fourth decade of life, you are in a phase of decline. One of the things that happens during this period is that you move from a skill acquisition period to extensive use of those skills that were previously acquired; these are things that are mastered and done without thinking.

You spend much of the day working without being consciously involved in what you are doing... I went through this without giving much thought to the physical activities of driving. I'm basically withdrawn.

Modern culture has greatly contributed to this. Modern culture is all about creating surprises... about limiting stimulation on one level so that we can engage in something like an abstract level of action. We are no longer interested in details. We are no longer interested in recognizing the details of what we see, hear or feel, and our brains are slowly deteriorating."Doctor Merzenich