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Anais da Academia Brasileira de Ciências

Print version ISSN 0001-3765On-line version ISSN 1678-2690

An. Acad. Bras. Ciênc. vol.73 no.2 Rio de Janeiro June 2001

Response of the Brain to Enrichment*


Department of Integrative Biology, 3060 Valley Life Sciences Building University of California, Berkeley, CA94720, USA

Manuscript got on March 5, 2001; accepted for publication on March 12, 2001; presented by LENY A. CAVALCANTE


Before 1960, the brain was thought about by researchers to be immutable, subject only to hereditary regulate. In the beforehand sixties, however, investigators were seriously speculating that ecological influences might be capable of changing brain framework. By 1964, two research laboratories showed that the morphology and chemistry or physiology of the brain could be experientially changed (Bennett et al. 1964, Hubel and also Wiesel 1965). Since then, the capacity of the brain to respond to ecological input, especially "enrichment,"" has come to be an welcomed reality among neuroscientists, educators and others. In truth, the demonstration that environmental enrichment deserve to modify structural components of the rat brain at any type of age changed prevailing presumptions about the brain"s plasticity (Diamond et al. 1964, Diamond 1988). The cerebral cortex, the location linked through greater cognitive handling, is more receptive than various other components of the brain to eco-friendly enrichment. The message is clear: Although the brain possesses a fairly constant macrostructural company, the ever-altering cerebral cortex, via its complicated microstyle of unknown potential, is powercompletely shaped by experiences before birth, throughout youth and, in reality, throughout life. It is vital to note that enrichment impacts on the brain have consequences on behavior. Parental fees, educators, policy equipments, and people have the right to all benefit from such knowledge. Key words: enrichment, cerebral cortex, hippocampus, aging, adult neurogenesis, dendrites.


Can experience develop measurable transforms in the brain? The hypothesis that transforms occur in brain morphology as an outcome of suffer is an old one. In 1815 Spurzheim asked whether body organ size might be boosted by exercise. He reported that the brain as well as muscles can boost with exercise "because the blood is brought in better abundance to the parts which are excited and also nutrition is perdeveloped by the blood."" In 1874 Charles Darwin stated that the brains of domestic rabbits were substantially diminished in mass in comparichild with those from the wild because, as he concluded, these pets did not exert their intellect, instincts, and also senses as a lot as did animals in the wild. However before, it was not till the 1960s, that the initially regulated research studies in animals demonstrated that enriching the eco-friendly problem in which they were confined can alter both the chemistry and also anatomy of the cerebral cortex and also, consequently, improve the animals" memory and discovering ability.

In these at an early stage experiments just the brains of young animals were studied. Although many were impressed to learn that the cerebral cortex might boost its thickness in response to enriched living conditions, they increased the question around whether enrichment could similarly impact older pets. Once middle-aged rats brains proved positive responses to enrichment, the next action was to experiment with very old pets. Once aobtain, increases in cortical thickness were found. It then became essential to find what was responsible for these transforms.

One step at a time, the level of morphological alters - from neuronal soma dimension, to number and also size of dendrites, to kinds and also numbers of dendritic spines, to synaptic thickening, to capillary diameter, and also to glial types and also numbers - was examined. Age, sex, duration of expocertain, and so on were important variables that had actually to be tested in brand-new experiments.

Many of the standard information reported on the enrichment paradigm and its impact on brain and also behavior have actually built up through research studies on the rat. Effects of enriched and also impoveriburned settings on the nerve cells and also their neurotransmitters in the cerebral cortex have actually now been generalised to a number of mammalian and also avian species (Rosenzweig and also Bennett 1996). Some corroborating studies discussed herein affiliated cats and primates, and isolated studies in human topics. For instance, Jacobs et al. (1993) using an isolated portion of the huguy cerebral cortex responsible for word understanding, Wernicke"s location, compared the results of enrichment in tconcern from deceased individuals that had actually had actually a college education and learning and from those that had had actually only a high school education. They demonstrated that the nerve cells in the college-educated confirmed even more dendrites than those in the last. (Tproblem was acquired from the Veteran"s Hospital in west Los Angeles.) Experiments on humale tproblem generally support the information obtained from studies in the rat, and also, consequently, benefit from these animal research studies. We can currently safely say that the standard concept of brain changes in response to enrichment hold true for a large range of animals and for humans.


What carry out we mean by "enrichment"" for the rats that have actually served as the pet of choice for most of these studies? Thirty six Long-Evans rats were sorted into 3 speculative conditions utilizing 12 animals in each group: 1) enriched 2) standard or 3) impoverimelted environments. All animals had actually cost-free accessibility to food and also water and also similar lighting conditions. Ultimately, it was identified that pets maintained in their particular settings from the age of 30 days to 60 days occurred the the majority of comprehensive cerebral cortical transforms. For the enriched atmosphere, the 12 animals lived together in a big cage ( 70 x 70 x 46 cm) and were provided 5-6 objects to check out and also climb upon (e.g., wheels, ladders, small mazes). The objects were readjusted 2 to three times a week to carry out newness and challenge; the frequent replacement of objects is a crucial component of the enriched problem. The combination of "friends"" and also "toys"" was establiburned early on by Krech as necessary to qualify the experiential environment as "enriched."" (Krech et al. 1960). For the standard environment, the pets were hoprovided 3 to a little cage ( 20 x 20 x 32 cm) with no exploratory objects. For the impoveriburned setting, one pet remained alone in a small cage with no exploratory objects.

The numbers of animals placed in these separate problems were based upon the manner in which the program housing was establiburned in the rat nest. Three rats in a cage has actually been taken into consideration typical for all experimental job-related over the decades. Because prior to these experiments no one had actually designed research studies to research brain transforms in response to various ecological conditions, the decisions around what represented "impoverishment"" and what represented "enrichment"" was even more arbitrarily than scientifically reasoned.

After 30 days in their corresponding settings, all animals were anesthetized before the brains were rerelocated for comparikid among the three teams. Twenty micrometer frozen sections were reduced and stained, and the thickness of the frontal, parietal and occipital cortices were measured. Results suggested plainly that the cortex from the enriched group had increased in thickness compared with that living in conventional problems, whereas, the brains from the impoveriburned group decreased compared to the typical. Due to the fact that the nerve cells were farther acomponent in the enriched vs. the impoverished brains, it was assumed that the significant component of the brain alters due to enrichment had actually to perform through alterations in the dendritic branching. With more thorough researches, the cortical thickness increases were uncovered to be because of a number of components, including increased nerve cell dimension, number and also length of dendrites, dendritic spines, and length of postsynaptic thickening as measured on electron microscopic images of synapses. (Diamond et al. 1964 and 1988).

In the initial experiments designed to check out the influence of an enriched environment on the brain of post-weaned rats, just enriched and also impoverimelted teams were used. Rats were kept in their respective atmospheres from 25 to 105 days of age because tright here were no accessible information on just how lengthy it would require to develop chemical or structural alters in the cortex. Chemical and anatomical dimensions taken from these pets confirmed substantial distinctions in between the 2 teams - in cortical thickness, cortical weight, acetylcholinesterase, cholinesterase, protein and also hexokinase levels, (Bennett et al. 1964, Diamond et al. 1964). In these initial experiments, however, it was not clear if the changes were due to enrichment or impoverishment because tbelow were no conventional conditions establiburned as controls.

Nonethemuch less, the differences in cortical thickness via this 80-day expocertain to the 2 ecological conditions were not as excellent as throughout the 30-day expocertain. Consequently, in succeeding experiments, the period of expocertain to the experimental conditions was lessened from 80 days to 30 days, then 15 days, 7 days and also ultimately to 4 days. At each of these intervals, pets from the enriched setting verified rises in cerebral cortical thickness in some areas yet not in others. For example, in the male animals exposed for 80 days to enriched conditions, the somatosensory cortex did not show substantial changes, whereas male pets exposed for 30 days did construct significant differences in the somatosensory cortex. The occipital cortex verified substantial changes for both the 80- and the 30-day experiments, yet, aacquire, the differences were higher at 30 days than at 80 days. It is feasible that the longer expocertain offered to increase cortical thickness in the early days of enrichment yet that over time the ecological problem came to be monotonous and also this result decreased. In later on experiments the experimental conditions were modified to try to develop what the major factors were that developed the oboffered cortical changes. For example, was the impact linked through the number of rats exposed or to the presence of stimulus objects?

The new conditions contained one rat living alone in the large enrichment cage through the objects that were readjusted numerous times each week. The cortex of these rats did not display a far-ranging impact of enrichment. Twelve rats living together in the big cage without the stimulus objects did not present as great an impact as 12 rats living via the stimulus objects. In other words, the combicountry of social problems and also constant exposure to new stimulus objects were essential for the pets to gain the full impact of enrichment.

Establishing what constitutes "enrichment"" for humans is even more problematic. Not just are managed experiments not feasible, but no 2 human brains are similar. Individuals differ in their hereditary backgrounds and environmental inputs. Furthermore, what is considered enrichment for one individual may be fairly various for one more. Yet, as stated previously, the enrichment effect was noticeable in Wernicke"s location from measurements of the amount of dendritic branching in brain tproblem from college-educated people versus that from high school-educated world. The standard finding of dendritic development in response to eco-friendly stimulation shows up in all brains stupassed away to date. It would certainly appear that newness and challenge are necessary for the human cortex and also for that of pets.


Amongst the many kind of variables researchers have to take into consideration as they seek to understand and accurately translate the results of enrichment on the brain, age and gender are vital considerations. Enrichment has actually been presented to improve many kind of facets of cortical structure at any type of age - from prenatal to extremely old rats (904 days of age). The amount of readjust varies with the age of the pet. For instance, once a 30-day-old rat is put in an enriched atmosphere for 4 days, the effects are not as pronounced as they are in the 60-day-old-rat kept in enriched problems for 4 days. Is 4 days also short a time for the very young pet to readjust and also advantage from enrichment? A young pet maintained for 30 days in an impoverimelted environment mirrors diminished morphological development of its cortex as soon as compared to that of an adult pet maintained in impoverished conditions for 30 days. In additionally age-connected experiments, another component was included to the enrichment problems of old rats. In spite of significant increases in the size of the dendrites in the brains of 600-day-old rats that had actually been put in an enriched environment for 30 days (600 to 630 days), a number of of the old rats in this populace died.

To determine whether the enrichment conditions could be modified to extend the animals" life expectancy, the investigators included a new component: hand-holding the rats each day for several minutes while the ceras were cleaned. In an attempt to boost the life expectations of the rats, rats were inserted three to a cage after weaning at 25 days of age, and also maintained in these conventional conditions until they got to 766 days, at which time fifty percent went into enriched problems till they got to 904 days of age and fifty percent continued to be in the standard conditions. The just variable included was the daily hand-holding of the rats as they aged. Is it possible that handling the rats had extfinished their life span? Undoubtedly, many investigators have actually been amazed that these rats made it through to 904 days of age. The 904 day-old rats in enriched conditions emerged a cortex considerably thicker than the cortex of rats living in the conventional problems (Diamond 1988). These experiments available support to the thesis that the cerebral cortex is qualified of responding positively to an enriched environment at any age (See Fig. 1).


Experiments comparing the results of enrichment on male and female brains are few. Most enrichment research studies have been brought out on male brain to stop the compounding factors linked with the estrous cycle. In one study concentrated on gender, the female neocortex was found to respond in different ways from the male neocortex exposed to the very same kind of enrichment conditions (Diamond 1988). The male verified substantial transforms in cortical thickness in the occipital cortex, but no considerable transforms in the somatosensory cortex. (Although the right cerebral cortex in the brain of the male rat is thicker than the left, specifically in the visual or occipital area, an enriched environment shows up to change both the right and left cortex similarly.) In the female, the thickness of the occipital cortex boosted significantly in response to enrichment, although not as much as in the male, however the thickness of the somatosensory cortex raised substantially more in the female than in the male. In a follow-up experiment, yet, in which obstacles were piled up in front of the female food cup to administer a greater obstacle to her already enriched setting, the thickness of the occipital cortex increased as much as did that of the male without the extra challenge.

In rats whose testes were removed either at birth or at 30 days of age prior to the rats were placed in an enriched setting for 30 days, the rises observed in cortical thickness were similar to those of their littermates via intact testes. (Diamond 1988) These findings argued that testosterone is not implicated in the increases in cortical thickness observed in the brains of rats living in enriched atmospheres. Due to the fact that sex differences were evident in the responses of the animals to enrichment, interest was currently focused on the brains of pregnant rats, in which the concentrations of sex steroid hormonal concentrations are greatly transformed. The brains of female rats living in the enriched atmosphere from 60 to 90 days and then becoming pregnant and returning to enrichment until 116 days of age were compared in between nonpregnant and also pregnant pets living in an impoverimelted setting for the same time periods. When pets from the 2 teams were autopsied at 116 days, no substantial distinctions in cortical thickness were uncovered. Evidently, pregnancy has actually an impact on the cerebral cortex regardless of whether the setting is impoveriburned or enriched.

These initial experiments, every one of which were replicated, clearly indicate sex distinctions in the brain"s response to enrichment. Having faced the independent variables, we turn to the impact of dependent variables in the enrichment paradigm. For these research studies, one need to look at: duration of expocertain, brain anatomy and also chemisattempt, visibility of lesions or fetal neocortical grafts, negative air ions, stress, physical task and also nutrition, and behavioral effects. These are questioned consequently listed below.

Duration: The duration of exposure to the enriched setting is plainly a far-reaching dependent variable that should be factored into research in this area. As brief a duration as 40 minutes of enrichment has been found to produce substantial changes in RNA and in the wet weight of cerebral cortical tproblem sampled. One day of enrichment was inenough to develop measurable changes in cortical thickness, whereas 4 consecutive days of exposure (from 60 to 64 days of age) to an enriched setting did create considerable increases in cortical thickness, however just in the visual association cortex (area 18) (Diamond 1988).

When young adult rats were exposed to 30 days of enrichment, but, the whole dorsal cortex, consisting of frontal, parietal and also occipital cortices, enhanced in thickness. Extfinishing the duration of the stay in enriched conditions to 80 days did not create any kind of higher boost in cortical thickness than that viewed at 30 days (in reality, it was regularly even less); however, the longer the rat stayed in the enriched conditions, the much longer the cortex preserved its boosted dimensions complying with go back to the traditional setting (Bennett et al. 1974). When we looked at age-associated distinctions in the context of duration of remain in the enriched environment, we found that old rats ( 766 days of age) placed in enriched conditions for 138 days verified a boost in cortical thickness that was quite similar to that observed in young adult rats (60 days of age) that had actually resided in enriched conditions for 30 days.

Anatomical and also chemical components: Early experiments, and those to follow in subsequent years, again demonstrated considerable distinctions in brain chemistry and also anatomy linked with enriched living problems. Anatomical rises include every one of the structural constituents measured in the cerebral cortex to date, such as cortical thickness (Diamond et al. 1964), nerve cell soma size, nerve cell nuclear dimension (Diamond 1988), dendritic dimensions (Hollomeans 1966, Greenough et al. 1973), dendritic spines, synaptic size and number (Mollgaard et al. 1971, Black et al. 1990), variety of glia, capillary diameter (Diamond 1988), dendritic number after lesions (McKenzie et al. 1990), and effective tissue grafts, (Mattskid et al. 1997). Chemical rises include: full protein, RNA-to-DNA proportion, cholinesterase-to-acetylcholine ratio, Nerve Growth Factor mRNA, cyclic AMP, choline acetyltransferase, cortical polyamines, NMDA (N Methyl D Aspartate) receptors, and also hexokinase, etc.

Lesions: Anvarious other variable hregarding perform through the affect of enriched problems on purposecompletely incurred brain lesions. In a 1990 research, 60-day-old rodents were exposed for 30 days to either an enriched or traditional environment two days after having actually obtained a lesion in the left frontal cortex that produced a motor dysattribute in the appropriate forepaw. Animals living in the enriched problem proved substantial increases in cortical dendritic branching in both hemispheres, the lesioned and also the non-lesioned sides, together with a far-ranging rerevolve of motor function in the best forepaw compared to those pets living in conventional problems (McKenzie et al. 1990).

Fetal neocortical graft: Similarly, providing an enriched setting to rats that had actually gone through fetal neocortical grafts one week after lesioning was found to improve behaviorally and to mitigate the atrophy in the thalamus, a significant structure beneath the cortex that offers neural input to the cortex (Mattschild et al. 1997). The reality that the fetal neocortical graft as soon as put in the lesioned cerebral cortex might proccasion atrophy in the underlying thalamus as a consequence of enrichment is of great interest to researchers considering the future opportunity of utilizing such grafts for brain-damaged people.

Air ions: The possibility that physical eco-friendly stimuli various other than those classically related to as "sensory"" could have an effect on the brain was tested experimentally by exposing rats living in enriched or traditional atmospheres to high concentrations of negative air ions. The experiments were undertaken to recognize whether the result of negative ions on serotonin, the putative second messenger cyclic-AMP, and also on cyclic GMP in the cerebral cortex, differ depending upon whether the pets lived in enriched or conventional conditions. Studies demonstrated that rats inserted in the enriched atmosphere in the existence of intensified negative air ions (ion density of 1 x 105) confirmed a significant decrease in serotonin, an impact not discovered in the brains of pets living in conventional conditions (Diamond et al. 1980). Measurements of cyclic AMP decreased too in the brains of the pets living in the enriched problems, but cyclic GMP did not. These outcomes suggest the importance of considering air top quality and also atmospheric problems in determining the brain"s response to enrichment.

Stress: The visibility or lack of stress and anxiety represents yet one more variable to be taken into consideration in such researches, certainly so in any kind of extrapolation of these findings to people. Stress is a significant factor in contemporary, fast-moving metropolitan life. Crowding, for instance, is considered stressful under conditions wright here competition for space or food is likely. Experiments were put up to assess the result of crowding on the brains of rats preserved in an enriched atmosphere. To develop a condition in which crowding would be proficient as stressful, 36 rats were put in an enrichment cage generally housing just 12 rats, and also maintained there for 30 days. The outcomes shown that, compared via rats living in conventional problems, the thickness of the medial occipital cortex enhanced considerably whether the enrichment cage hosupplied 12 or 36 animals, (Diamond et al. 1987). One hypothesis to come from this examine was that the animals" interaction via the playthings might be diverting their attention or entertaining them sufficiently to mitigate the tension of the crowded condition.

Chronic anxiety has actually been reported by Meaney et al. (1988) to produce excess glucocorticoids, which are toxic to neurons - especially those of the hippocampus. Aged rats are particularly breakable to chronic anxiety. The investigations of Meaney verified that enriching the living conditions of old rats, or managing them in their inelaborate, helps to prevent stress-associated hippocampal damage.

It is feasible that stress and anxiety deserve to be produced by increasing the frequency through which the miscellaneous objects in the enrichment cage are adjusted. In all previous studies, objects had actually been reinserted everyday or at leastern numerous times each week. Then the question was asked whether enhancing the frequency of altering the objects would certainly better boost the development of the cortical thickness, or, alternatively, would certainly it be skilled as a anxiety element, provided that the pets were inhibited from interacting via them in the even more leisurely manner to which they were accustomed. For these experiments, rats 60 to 90 days of age discovered their objects adjusted eexceptionally hour for three hours on 4 nights of each week for four consecutive weeks. Under this routine, the cerebral cortical thickness did not flourish significantly compared to cortices from rats whose objects were adjusted a number of times each week for 4 weeks (Diamond, unpublished.)

Corticosteroids, released under tension, have been shown to minimize cortical thickness and also future experiments would certainly be crucial to compare differences in corticosteroid levels in pets exposed to these differing conditions.

Behavior: Psychologists have well-known for a long time that early endure influences the adult performance of an animal. In experiments in the 1950s (Bingham and Griffiths 1952 and also Forgays and Forgays 1952) investigators were interested in determining just how much endure in facility atmospheres was important to develop a very intelligent adult animal and when, particularly, in the time of early on life these experiences had actually to take place. These research studies showed that every one of the pets maintained in enriched problems were better problem solvers than those via no enrichment; yet, in some other occasions, utilizing other tests, enriched rats did not percreate considerably much better than controls.

One of the many robust results of ecological enrichment on the actions of rats appears in the locations of learning and also memory. Investigators (York et al. 1989 and also Kempermann et al 1997) examining the impacts of enrichment in the rat brain have actually reported that new nerve cells build in the adult dentate gyrus, a space taking care of current memory handling. In the York experiments the rats were 60 to 90 days of age (truly adult animals) in the time of the enrichment suffer, whereas in the Kempermann experiments the mice were 21 to 40 days of age. These finding are significant because neurogenesis had actually not previously been uncovered in the cerebral cortex of the mammalian adult. Earlier research studies had actually discovered that enriched environments stimulate the development of dendrites in the dentate gyrus, and also just in female rats. (Juraska et al. 1985).

Physical Activity: One component of enrichment is the physical exercise involved in the animals" having actually to relocate about the cage, interacting with and also climbing upon the novel objects. These tasks appear to affect the motor cortex and also the hippocampus. Olskid et al. (1994) confirmed that rats living in enriched settings at 50 days of age verified better expression of the gene-encoding glucocorticoid receptors and also induction of genes for Nerve Growth Factors in the hippocampus.

Nutrition: Nutrition is plainly an important variable to think about in all studies dealing with brain and actions. Environmental enrichment and also impoverishment have pronounced impacts on nutritionally deficient animals. One research compared the results of environmental enrichment on the offspring of mom rats living on protein-rich or protein-deficient diets in the time of pregnancy (Carughi et al. 1990). The protein-rich diet confirmed advantageous for the healthy and balanced breakthrough of the cerebral cortical dendrites in young rats and also also even more so when combined through an enriched environment.

The cerebral cortical dendrites in rat pups from mothers through a protein-deficient diet were considerably much less well arisen than those of their countercomponents, however, of greater prominence, the cortex from the protein-deficient animals did not significantly boost via enrichment. On the other hand also, once protein-deficient pups were fed a protein-affluent diet and preserved in an enriched setting throughout their at an early stage postnatal life, cortical breakthrough boosted virtually to the level checked out in rat pups from mothers on a high-protein diet throughout pregnancy adhered to by postnatal enrichment. These data are incredibly encouraging, bereason they indicate the possibility of consisting of for shed brain development during pregnancy by enriching both the diet and the ecological problems in the time of the postnatal duration.

Anvarious other dietary element significant to optimal brain feature is glucose. The brain counts almost solely on glucose for its power. Synapses usage a great deal of power and glucose offers this energy. Although we know that different components of the brain use glucose at various prices, to learn which of 30 discrete brain areas were a lot of active in adult rats put in enriched living problems from 57 to 87 days of age, we stupassed away their radioenergetic glucose uptake in the time of this 30-day duration and also compared it through that of rats raised in standard problems (Diamond 1988). Aacquire, the cerebral cortex proved the best differences between enriched and nonenriched groups, yet, surprisingly, of the 2 groups, glucose uptake was reduced in rats preserved in enriched problems. We concluded from this finding that glucose uptake is more efficient in the brain of animals living in enriched atmospheres. Out of the 30 locations of the brain measured, consisting of the cortex, only one area showed significantly better glucose uptake in the enriched animals: the corpus callosum, specifically, the large mass of axons connecting the nerve cells between the two cerebral hemispheres. Could the axons forming the corpus callosum from the nerve cells in the cerebral cortex be more active than the nerve cell bodies from which they arise? Yet the ideal and also left cerebral cortices present comparable cortical thickness rises with enrichment because of the impacts on dendritic branching, however currently the information display that the rates of glucose utilization in both the frontal and also parietal cortices were 13% lower in the enriched rats than in the traditional regulate rats, a paradox to be untangled in the future.

Methodological issues associated via enrichment research study in humans: Of the substantial number of animal researches that yield outcomes of interemainder to human research, research studies on the affect of an enriched setting on brain development and also habits have the right to be of massive interemainder to humans. Regardless of similarities in some crucial respects between the brain of the rat and various other mammals, replicating or extrapolating from anatomical and chemical research studies carried out in pets is fraught via difficulty, for obvious reasons. Not just is it not presently feasible to manage all of the experimental variables at job-related in human beings, yet the diversity and also intricacy of humale endure militates against creating experiences similar to those supplied through lower pets.

However, these researches and also what few huguy studies have actually been done, suggest that there are measurable benefits to enriching an individual"s setting in whatever terms that individual perceives his prompt atmosphere as enriched. At the exceptionally least, this occupational shows that tright here are many type of methods for enhancing brain activity and behavior at all ages, and also that they can have pronounced impacts throughout the life span.


Antes de 1960, os cientistas consideravam o encéfalo como imutável, sujeito apenas ao contfunction genético. Entretanto, no início dos anos 60, alweapons pesquisadores especulavam seriamente que influências ambientais podiam ser capazes de alterar a estrutura cerebral. Por volta de 1964, dois laboratórios de pesquisa demonstraram que a morfologia e a química ou a fisiologia execute cérebro poderia ser modificada pela experiência (Bennett et al. 1964, Hubel e Wiesel 1965). Desde então, a capacidade perform cérebro a responder para responder a insumos ambientais, especificamente ao "enriquecimento"", tornou-se um fato aceito por neurocientistas, educadores e outros. De fato, a demonstração de que o enriquecimento ambiente pode modifiautomobile componentes estruturais execute cérebro de rato, em qualquer idade, alterou suposições prevalentes a respeito da plasticidade cerebral (Diamond et al. 1964, Diamond 1988). O córtex cerebral, a área associada com o processamento cognitivo exceptional, é mais receptivo do que outras partes do encéfalo ao enriquecimento ambiental. A mensagem é clara: embora o encéfalo possua uma organização macro-estrutural relativamente constante, o sempre-mutável córtex cerebral, com sua microarquitetura complexa de potencial desconhecicarry out, é fortemente moldacarry out pelas experiências antes carry out nascimento, durante a juventude e, em verdade, ao longo de toda a vida. É essencial que se note que os efeitos execute enriquecimento sobre o encéfalo têm consequências no comportamento. Pais, educadores, geradores de políticas e quaisquer indivíduos podem todos se beneficiar de tal conhecimento. Palavras-chave: enriquecimento, córtex cerebral, hipocampo, envelhecimento, neurogênese em adultos, dendritos.


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