merzenich monkey experiment quizlet

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• v.3(1); 2007 Aug

Language: English | French

Plastic Brains

Cerveaux plastiques, robert g. evans.

University of British Columbia, Vancouver, BC

Memories fade, alas, and more rapidly with age, though the aging brain holds more tenaciously to the longer past. Or does it? The brain may be continually editing those seemingly clear memories. That the immature brain constructs, “sculpts” itself by configuring its neural linkages to make best use of the sensory input received in early life has been known for decades. The more recent news is that mature brains also re-arrange these linkages as sensory inputs change. So what? Well, by some estimates inadequate stimulation in early childhood leaves 25% of Canadians neurally challenged by the modern world. Countries with systematic early child development programs show better results. Are there also opportunities for exploiting the plasticity of adult brains? (Or is that already happening, all around us?)

Les souvenirs s’estompent, hélas, et encore plus rapidement avec l’âge, bien que le cerveau vieillissant ait davantage tendance à se rappeler le passé plus lointain. Est-ce réellement le cas? Il se pourrait que le cerveau soit continuellement en train de modifier des souvenirs apparemment clairs. On sait depuis des décennies que le cerveau encore en développement se construit et se « façonne » en configurant ses liens neuronaux de manière à faire le meilleur usage possible des données sensorielles reçues tôt dans la vie. Selon les données récentes, les cerveaux pleinement développés réorganisent ces liens à mesure que les données sensorielles changent. Et alors? D’après certaines estimations, 25 % des Canadiens affichent des déficiences neuronales qui les limitent dans le monde moderne en raison d’une stimulation inadéquate dans la première enfance. Les pays dotés de programmes systématiques de développement des jeunes enfants présentent de meilleurs résultats. Y a-t-il aussi des occasions d’exploiter la plasticité des cerveaux adultes? (Ou cela se produit-il déjà tout autour de nous?)

“ T’aint what a man don’t know as makes him ignorant, it’s what he knows that aint so.” – variously attributed

I seem to be forgetting things lately. My memory used to be excellent – at least that’s how I remember it – and my (very) long-term memory remains pretty good. But it is not clear how great an advantage that is. As the late middle-aged chap in the New Yorker cartoon says wistfully, “I think I’ve learned quite a few things over the years. But there doesn’t seem to be much demand for them.” Remembering what my wife told me this morning might be more useful.

This seems to be the common experience of aging, just part of the general decay (a.k.a. golden years). My mother-in-law referred to it as “CRAFT.” (It’s an acronym.)

But there is something else, perhaps a bit more interesting. The contents of the long-term memory, still apparently very clear, seem to shift over time. If I go back to check the sources, they do not always exactly match. Memory tells a simpler, neater, more consistent story than the originals. It seems to have been edited – selectively.

There is an obvious way of dealing with such lapses: assert confidently and never look things up. As Satchel Paige said, “Don’t look back. Something might be gaining on you.” If you are fortunate, no one else will remember, or still have the originals.

Occasionally, however, some other scholarly pack-rat does. Milton Friedman’s famous claim to have distilled his 1950s monetary doctrines from some deep-rooted and subtle “oral tradition” at the University of Chicago ran into just that problem. The equally distinguished, though much less celebrated, monetary scholar Don Patinkin, a contemporary of Friedman’s at Chicago, had kept his graduate class notes. These contained no trace of the doctrines that Friedman had attributed to their eminent instructors. Paul Samuelson, an undergraduate at Chicago in those years, later made the same observation: “I believe that this nominated myth should not be elevated to the rank of plausible history of ideas” (Barnett 2004: 526).

Friedman was engaged in constructing a set of economic doctrines to advance his political ideology – not the first to do that! To add weight and plausibility in a then relatively hostile intellectual environment, he recruited an array of distinguished (and conveniently defunct) supporters. But was he deliberately lying? Perhaps not. The more interesting possibility is that he sincerely believed his own myth. His brain may have been editing his memory to create the story that assisted his ideological agenda. Thank heavens you and I never do that.

This could be scary stuff. But the fact that Friedman appears to have made up the story – and his doctrines – from whole cloth has had no apparent bearing on their subsequent impact. Maybe Satchel Paige got it right.

One-Eyed Kittens

That the immature brain edits itself has long been known. Hubel and Wiesel shared the Nobel Prize in 1981 for demonstrating that the developing brain organizes its own neuronal wiring in response to the information being received from peripheral sense organs – eyes, ears and so on. In the classic experiment, the lids of one of a kitten’s eyes are sewn together when the animal is four weeks old, and opened again at six weeks. The kitten will now have only monocular vision; it will not able to see out of the perfectly normal and healthy eye that was temporarily sewn shut during this critical period of neural development.

Subsequent microscopic examination of the experimental animal’s visual cortex shows that the neurons are now linked dendritically so as to process information only from the eye that was not sewn up. The kitten is blind not in the sewn-up eye itself, but in the brain that is no longer capable of responding to electrical signals from that eye. Processing capacity had been reallocated, during the critical four- to six-week period of development, away from the apparently non-functioning peripheral organ. Once that period is past, the brain does not go back to revisit the allocation; the kitten is permanently monocular. The brain has organized itself – establishing the connections between neurons – to make best use of the sensory data coming in during the critical period.

Research ethics committees are unlikely to approve replication of this experiment in humans; there might also be legal complications. But everyone is aware that there is a critical period, perhaps somewhat less well mapped, for the learning of languages. Early exposure to two or several languages results in children becoming multilingual as easily and naturally as they learn their “native” language. But try it yourself: for an adult to learn another language is certainly possible, but the task is much more difficult and is rarely as well achieved.

There are two fundamental points here. First, the brain is “plastic” for a more or less extended period after birth. The immature brain is busy organizing itself – establishing the pattern and density of neuronal linkages (more is better) in response to the patterns of sensory data coming in. Neuronal linkages that are not receiving input are pruned away. The mature brain is “sculpted,” in Cynader’s (1994) felicitous phrase, from a huge initial oversupply of neurons in a process of competitive cooperation. Those that are successful in becoming active links in networks processing sensory input survive; the others do not.

Second, however, this sculpting process takes place according to a relatively precise sequence, so that different phases of development are coordinated. Critical periods, once missed, are gone forever – like the kitten’s binocular vision. Other brain processes may be mobilized to remedy deficits – like the learning of a language in adult life – but they will never work as well. These two fundamental ideas drive the efforts in Canada to establish public policies and institutions to promote early childhood development (ECD), to which we will return below.

All this is interesting enough, but what does it have to do with me or with Milton Friedman? The plasticity of the developing brain would seem to lead naturally to the mature brain, with all its neuronal linkages in place and, for better or for worse, impervious to further external input. (There seems to be a lot of casual empirical support for this view.) But in fact, it is possible to teach an old dog new tricks – and it had better be, if the rhetoric of “lifelong learning” is to have any correspondence to the real world.

There are optimistic examples. London taxi drivers must “do the knowledge,” learn the intricacies of the city’s streets, to qualify to drive one of those big black cabs. Subsequent brain scans of drivers found that this demanding task was associated with enlargement of the hippocampus, a region associated with learning (Maguire et al. 2000). The adult brain apparently created the extra neuronal capacity to acquire and store all this new information.

The Monkey’s Finger

The plasticity of the adult brain is addressed by Doidge (2007). He highlights in particular the work of Michael Merzenich, whose research program uses techniques that go back to the pioneering work of Wilder Penfield at the Montreal Neurological Institute in the 1930s. Penfield used electrical probes to stimulate particular areas of the exposed brains of conscious patients. As patients reported their sensations, he was able to “map” the brain, identifying the regions in which different types of information were processed and stored, and their linkages via the nervous system to other parts of the body. With much finer instrumentation, Merzenich and his associates have been able to “micro-map” areas of the adult monkey brain exposed in living experimental animals.

The striking finding is that these maps do not stay still. The boundaries between micro-areas shift, over relatively short periods of time, depending upon how intensely they are being used.

As a leading example, a monkey’s hand, like the human hand, is linked to the brain by three main nerves (radial, medial and ulnar) that transmit electric signals to specific and adjacent areas of the brain. Viewed by magnetic resonance imaging, these areas “light up,” indicating neuronal activity, in response to stimulation of the corresponding regions of the hand. Modifying or blocking the transmission of signals from hand to brain not only changes or shuts down the neuronal activity in that micro-region, but also leads to rearrangement of the linkages among the neurons themselves.

In one experiment, the medial nerve was cut; in a more extreme intervention, the middle finger served by that nerve was amputated. The corresponding brain area became inactive. But, some months later, that area was remapped in the experimental animal and found to respond (light up the MRI image) to stimuli in adjacent areas of the hand served either by the radial or by the ulnar nerve. The neurons no longer receiving signals from the medial nerve had been appropriated by the networks responding to signals from the other, still functioning nerves. Just as in the developing kitten brain, unused neuronal processing capacity in the adult monkey brain was reassigned, and over quite a short time interval.

Another intriguing result emerged when two of the fingers of an experimental animal, served by different nerves, were linked together so that they could only be moved simultaneously. Later micro-mapping indicated that the separate neuronal networks that had previously responded to the signals from the distinct fingers/nerves were now merged into a single network, responding to the signals from what was now in effect one “finger.”

Merzenich’s monkey experiments demonstrate that the mature brain rearranges itself in response to external stimuli. This finding would appear to provide an increasingly secure neurological basis for the common wisdom, “Use it or lose it.” Why does one have to keep practising a foreign language, or a physical skill? Because if the neurons that support it are left unused, they will be recruited by some other network.

But there is clearly more to the story. High levels of skill – in professional athletes, musicians or surgeons, for example – do require very frequent practice. It is well established that surgeons who operate infrequently have on average poorer outcomes. But if the “edge” is lost for lack of practice, it is also regained by further practice. And that further practice builds on a basic level of skill that, once acquired, remains for a long time, perhaps for life. Important neuronal linkages apparently persist, even without continuing stimulation. One never forgets how to ride a bicycle, for example. Nor does one’s native language require constant practice.

All this is very interesting, but the findings for both immature and mature brains show self-reorganization in response to external stimuli, or lack of it. That is still some considerable distance from explaining the mechanisms whereby the brain quietly goes about editing its own contents to make them more compatible with its proprietor’s interests, purposes or ideological agenda. The human heart may be “deceitful above all else, and desperately wicked”; I suspect the human brain is only trying to be helpful. How does the internally driven editing process work?

Kids and Kittens: ECD and the Children Left Behind

Furthermore, what does all this have to do with health policy? In the case of the developing brain, quite a lot. Here is where we come back to ECD, and the evidence assembled by McCain and Mustard in the Early Years Studies (McCain and Mustard 1999; McCain et al. 2007).

The socio-economic gradient in health status is well known: higher income, education and social status are closely associated with better health and longer life expectancy. Perhaps less widely known is that the gradients in adult health correspond to earlier gradients in readiness to learn at school entry, in school performance, in post-secondary education, in contacts with the justice system, in attachment to employment and quality of jobs (Keating and Hertzman 1999). These self-reinforcing life trajectories are strongly influenced by the early life experiences that promote or inhibit the neural development of the immature brain – even including the expression or suppression of particular genes. Experiences become embedded in “coping styles,” or patterns of behavioural and biological responses, to the later opportunities and challenges of life. The so-called “lifestyle choices” by which socio-economic health gradients are so often trivialized have deep roots in early environments and neural development.

These social gradients in health, literacy, school and work performance are much steeper in some societies than in others, meaning that they can be modified through public policies. Societies with flatter gradients are not only healthier but have higher literacy and educational attainment, lower poverty rates and smaller prison populations, and just plain work better. And they have serious ECD programs.

This is now all pretty well understood, though the evidence has yet to penetrate our political leadership. By some estimates, about 25% of Canadian children reach adulthood without the competencies they need to cope in the modern economy. The result is a large burden of social overhead costs, and of sheer human distress. It does not have to be this way. But ideology and economic interest trump science.

Messing with Your Head – To What End?

Well and good, but what about the mature brain? The evidence for continuous neuronal reorganization is intriguing, but how far does it take us? Presumably I too can reorganize my own neurons by duct-taping two of my fingers together for six months, but the operational significance is unclear.

The fact that the micro-map of the brain changes in response to particular external stimuli suggests the possibility of therapies for some forms, at least, of brain injury or illness, though these may be a long way off.

There are indications from brain scans that rigorous training in meditation enables adepts to modify their own brain functions. The Dalai Lama has an understandable interest in these observations, but I no longer have 20 years to spare. (I used that time studying economics – wonder what that did to my brain?)

There is also evidence that cultural norms, habits of thought, ideological preconceptions, even perceptions themselves may be neuronally embedded (“I wouldn’t have seen it if I hadn’t believed it”). This has rather disturbing implications.

If the Jesuits’ insight (“Give me the child until he is seven and I will show you the man”) is as solidly rooted neurologically as the one-eyed kittens, that suggests pretty radical limitations on the communicative and, a fortiori , the motivational power of “fact and argument” – evidence, as we might call it. In particular, school systems fragmented along sharply divergent religious or cultural lines may produce a citizenry whose brains are actually wired differently. And immigration … let’s not go there. No wonder politics is such a difficult art.

So what does it all mean? Frankly, I don’t know. And I still don’t know why or how my brain is editing my memory – in response to some sort of internal stimulus, I guess. To support further wholesale returns of conjecture, we probably need a greater investment of fact. Stay tuned.

• Barnett W.A. An Interview with Paul A. Samuelson. Macroeconomic Dynamics. 2004; 8 :519–42. Retrieved July 9, 2007. http://129.3.20.41/eps/mhet/papers/0405/0405006.pdf . [ Google Scholar ]
• Cynader M.S. Mechanisms of Brain Development and Their Role in Health and Well-being. Daedalus. 1994; 123 (4):155–66. [ Google Scholar ]
• Doidge N. The Brain That Changes Itself. New York: Viking; 2007. [ Google Scholar ]
• Keating D.P., Hertzman C. Developmental Health and the Wealth of Nations. New York: Guildford Press; 1999. [ Google Scholar ]
• Maguire E.A., Gadian D.G., Johnsrude I.S., et al. Navigation-Related Structural Change in the Hippocampi of Taxi Drivers. Proceedings of the National Academy of Sciences. 2000; 97 (8):4398–403. [ PMC free article ] [ PubMed ] [ Google Scholar ]
• McCain M.N., Mustard J.F. Early Years Study: Final Report. Toronto: Children’s Secretariat; 1999. [ Google Scholar ]
• McCain M.N., Mustard J.F., Shanker S. Toronto: Council for Early Child Development; 2007. Early Years Study 2: Putting Science into Action. [ Google Scholar ]

November 21, 2023

The Brain Isn’t as Adaptable as Some Neuroscientists Claim

The idea of treating neurological disorders by marshaling vast unused neural reserves is more wishful thinking than reality

By Tamar Makin & John Krakauer

Artur Kamalov/Alamy Stock Photo

The human brain’s ability to adapt and change, known as neuroplasticity, has long captivated both the scientific community and the public imagination. It’s a concept that brings hope and fascination, especially when we hear extraordinary stories of, for example, blind individuals developing heightened senses that enable them to navigate through a cluttered room purely based on echolocation or stroke survivors miraculously regaining motor abilities once thought lost.

For years, the notion that neurological challenges such as blindness, deafness, amputation or stroke lead to dramatic and significant changes in brain function has been widely accepted. These narratives paint a picture of a highly malleable brain that is capable of dramatic reorganization to compensate for lost functions. It’s an appealing notion: the brain, in response to injury or deficit, unlocks untapped potentials, rewires itself to achieve new capabilities and self-repurposes its regions to achieve new functions. This idea can also be linked with the widespread, though inherently false, myth that we only use 10 percent of our brain, suggesting that we have extensive neural reserves to lean on in times of need.

But how accurate is this portrayal of the brain’s adaptive abilities to reorganize? Are we truly able to tap into reserves of unused brain potential following an injury, or have these captivating stories led to a misunderstanding of the brain’s true plastic nature? In a paper we wrote for the journal eLife , we delved into the heart of these questions, analyzing classical studies and reevaluating long-held beliefs about cortical reorganization and neuroplasticity. What we found offers a compelling new perspective on how the brain adapts to change and challenges some of the popularized notions about its flexible capacity for recovery.

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The roots of this fascination can be traced back to neuroscientist Michael Merzenich’s pioneering work , and it was popularized through books such as Norman Doidge’s The Brain That Changes Itself . Merzenich’s insights were built on the influential studies of Nobel Prize–winning neuroscientists David Hubel and Torsten Wiesel, who explored ocular dominance in kittens . Their experiments involved suturing one eyelid of a kitten, then observing the resulting changes in the visual cortex. They found that the neurons in the visual cortex, which would normally respond to input from the closed eye, started responding more to the open eye. This shift in ocular dominance was taken as a clear indication of the brain’s ability to reorganize its sensory processing pathways in response to altered sensory experiences in early life. When Hubel and Wiesel tested adult cats, however, they were unable to replicate these profound shifts in ocular preference, suggesting that the adult brain is far less plastic.

Merzenich’s work demonstrated that even the adult brain is not the immutable structure it was once thought to be. In his experiments, he meticulously observed how, when a monkey’s fingers were amputated, the cortical sensory maps that initially represented these fingers became responsive to the neighboring fingers. In his account, Merzenich described how areas in the cortex expanded to occupy, or “take over,” the cortical space that had previously represented the amputated fingers. These findings were interpreted as evidence that the adult brain could indeed rewire its structure in response to changes in sensory input, a concept that was both thrilling and full of potential for enhancing brain recovery processes.

These seminal studies, along with many others focusing on sensory deprivation and brain injuries, underscored a process termed brain remapping, where the brain can reallocate one brain area—belonging to a certain finger or eye, for instance—to support a different finger or eye. In the context of blindness, it was assumed that the visual cortex is repurposed to support the enhanced hearing, touching and smelling abilities that are often displayed by individuals with blindness. This idea goes beyond simple adaptation, or plasticity, in an existing brain area allocated to a specific function; it implies a wholesale repurposing of brain regions. Our research reveals a different story, however.

Driven by a blend of curiosity and skepticism, we chose 10 of the most quintessential examples of reorganization in the field of neuroscience and reassessed the published evidence from a fresh perspective. We argue that what is often observed in successful rehabilitation cases is not the brain creating new functions in previously unrelated areas. Instead it’s more about utilizing latent capacities that have been present since birth. This distinction is crucial. It suggests that the brain’s ability to adapt to injury does not typically involve commandeering new neural territories for entirely different purposes. For instance, in the cases of Merzenich’s monkey studies and Hubel and Wiesel’s work on kittens, a closer examination reveals a more nuanced picture of brain adaptability. In the former case, the cortical regions did not start processing completely new types of information. Rather the processing abilities for the other fingers were ready to be tapped in the examined brain area even before the amputation. Scientists just had not paid much notice to them because they were weaker than those in the finger that was about to be amputated.

Similarly, in Hubel and Wiesel’s experiments, the shift in ocular dominance in kittens did not represent the creation of new visual capabilities. Instead there was an adjustment in preference for the opposite eye within the existing visual cortex. The neurons originally attuned to the closed eye did not acquire new visual capabilities but rather heightened their response to the input from the open eye. We also did not find compelling evidence that the visual cortices of individuals who were born blind or the uninjured cortices of stroke survivors developed a novel functional ability that did not otherwise exist since birth.

This suggests that what has often been interpreted as the brain's capacity for dramatic reorganization through rewiring might actually be an example of its ability to refine its existing inputs. In our research, we found that rather than completely repurposing regions for new tasks, the brain is more likely to enhance or modify its preexisting architecture. This redefinition of neuroplasticity implies that the brain’s adaptability is marked not by an infinite potential for change but by a strategic and efficient use of its existing resources and capacities. While neuroplasticity is indeed a real and powerful attribute of our brain, its true nature and extent are more constrained and specific than the broad, sweeping changes that are often depicted in popular narratives.

So how can blind people navigate purely based on hearing or individuals who have experienced a stroke regain their motor functions? The answer, our research suggests, lies not in the brain’s ability to undergo dramatic reorganization but in the power of training and learning. These are the true mechanisms of neuroplasticity. For a blind person to develop acute echolocation skills or a stroke survivor to relearn motor functions, intensive, repetitive training is required. This learning process is a testament to the brain’s remarkable but constrained capacity for plasticity. It’s a slow, incremental journey that demands persistent effort and practice.

Our extensive analysis of many of the cases previously described as “reorganization” suggests there are no shortcuts or fast tracks in this journey of brain adaptation. The idea of quickly unlocking hidden brain potential or tapping into vast unused reserves is more wishful thinking than reality. Understanding the true nature and limits of brain plasticity is crucial, both for setting realistic expectations for patients and for guiding clinical practitioners in their rehabilitative approaches. The brain’s ability to adapt, while amazing, is bound by inherent constraints. Recognizing this helps us appreciate the hard work behind every story of recovery and adapt our strategies accordingly. Far from being a realm of magical transformations, the path to neuroplasticity is one of dedication, resilience and gradual progress.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of  Scientific American.

• TED Speaker

Michael Merzenich

Why you should listen.

One of the foremost researchers of neuroplasticity, Michael Merzenich's work has shown that the brain retains its ability to alter itself well into adulthood -- suggesting that brains with injuries or disease might be able to recover function, even later in life. He has also explored the way the senses are mapped in regions of the brain and the way sensations teach the brain to recognize new patterns.

Merzenich wants to bring the powerful plasticity of the brain into practical use through technologies and methods that harness it to improve learning. He founded Scientific Learning Corporation, which markets and distributes educational software for children based on models of brain plasticity. He is co-founder and Chief Science Officer of Posit Science, which creates "brain training" software also based on his research.

Merzenich is professor emeritus of neuroscience at the University of California, San Francisco.

What others say

“Merzenich is perhaps the most recognizable figure in brain plasticity and how one develops competence through experience and learning.” — Dominique M. Durand

Michael Merzenich’s TED talk

Growing evidence of brain plasticity

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Psychology > Biological - Neuroplasticity (Experiments) > Flashcards

Biological - Neuroplasticity (Experiments) Flashcards

Merzenich et al (1984) aim

○ TO investigate how cortical remapping occurs in the sensory cortex.

Merzenich et al (1984) method

○ Sensory inputs of the fingers of each hand were mapped. § Electrodes were inserted in the cortical area and tested by researchers to map it out. ○ The third digit (middle finger) was amputated. ○ 62 days later a remapping was done to see how the cortical are had changed.

Merzenich et al (1984) results

○ The first mapping showed § There were 5 distinct areas in the brain for each finger. § Adjacent fingers were found adjacently in the cortex. ○ The Second mapping showed § After the amputation the adjacent areas of the cortex spread to occupy unused area.

Merzenich et al (1984) conclusion

○ Cortical remapping of sensory inputs from the hand occur in 62 days in owl monkeys.

Merzenich et al evaluation

Permanent harm to owl monkeys.

Dragaski et al (2004) aim

Investigate whether the human brain can change its structure in response to environmental demands

Draganski et al (2004) method

○ Sample § Random Sampling design § Self-selected sample ○ They allocated a sample of volunteers into two groups. § Jugglers § Non-Jugglers § They made sure no participant had juggling experience. ○ The first brain scan was performed before the experiment. ○ Participants in the juggler group began to learn juggling for 3 months. ○ After the 3 month period a second brain scan was performed. ○ The participants were instructed not to juggle for 3 months. ○ A third brain scan was performed. ○ The control group had brain scans at the same time and did not learn juggling.

Draganski et al (2004) results

○ Comparison of the first brain scans showed no differences. ○ Comparison of the second brain scan showed that § Jugglers had more grey matter in the brain. □ Especially in the mid temporal area in both hemispheres. § These areas were known to be implicated with movement. ○ Comparisons of the third brain scan showed § Decrease of differences. § Significant more grey matter than control group. ○ Better jugglers had much more significant brain changes.

Draganski et al (2004) conclusion

○ As participants learnt a juggling routine, certain areas of the brain grow. ○ A lack of practice leads to a shrink but not to the initial state.

Draganski et al (2006) aim

○ Investigate the effect of reading on the brain.

Draganski et al (2006) method

○ Sample § 38 medical students. ○ He scanned the brains of the students 3 months before exams. ○ He then scanned the brain after examination. ○ He then scanned the brain a third time after 3 months of the exam.

Draganski et al (2006) results

○ No differences in regional grey matter at the baseline. ○ Two major changes § Increase of grey matter in parietal cortex □ Did not decrease by the third scan § Increase of grey matter in the posterior hippocampus.

Draganski et al (2006) conclusion

○ Stress lead to the reduction of grey matter in hippocampal regions. This meant that learning did make the brain gain grey matter.

Maguire et al (2000) aim

○ Investigate the brains of London Taxi drivers.

Magurie et al (2000) method

○ Sample § 16 right handed male taxi drivers. § Average pre-licensning time 2 years. § Average 14 years experience. § 50 healthy right handed male non-drivers ○ Both groups got their brain scanned. § MRI (Magnetic Resonance Imaging)

Maguire et al (2000) results

○ Increased brain matter in taxi driver brains compared to control subjects in posterior hippocampus. ○ At the same time control subjects had a increased grey matter region in the anterior hippocampus. ○ Significant shift of grey matter from anterior to posterior hippocampus. Brain matter shifted from the front to the back.

Maguire et al (2000) evaluation

○ Bidirectional ambiguity due to quasi experiment.

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Phantom Limbs and Rewired Brains

• Urmila Ranadive archive page

Phantom arms, legs, fingers and toes: seemingly the stuff of horror movies. Yet for nearly 70 percent of the 4 million amputees in the United States, vivid sensations in missing body parts-such as pressure, tingling, warmth, cold, and pain that can be both constant and excruciating-are all too real.

Phantom limbs have puzzled scientists for years. But recent studies have shed light on possible mechanisms underlying the phenomenon, including evidence that neurons in the brain that receive input from a limb may rewire themselves to seek input from other sources after the limb is amputated. These findings challenge the long-standing belief that the brain is immutable beyond a certain age and are leading researchers to develop new therapies for victims of phantom-limb pain and some spinal-cord injuries.

For years, psychologists attributed phantom-limb sensations to “wish fulfillment,” a purely psychological condition. Then, in 1984, a team led by Michael Merzenich, a neuroscientist at the University of California at San Francisco, conducted experiments that began to explain phantom limbs as a true physiological response. Merzenich and his colleagues first amputated the middle fingers from a group of adult owl monkeys and later stimulated the digits on the hand of each monkey that were adjacent to the amputation stump.

Placing microelectrodes, which detect electrochemical changes in actively firing neurons, into various areas of the monkeys’ brains, Merzenich found that the region of the cortex that originally fired in response to stimulation of the amputated finger was now triggered every time he touched the two adjacent fingers. The neurons had not responded to stimulation of these fingers before the amputation.

In 1991, Timothy Pons, a neuroscientist at the Laboratory of Neuropsychology at the National Institute of Mental Health, expanded on Merzenich’s findings. Working with adult macaque monkeys, Pons and his colleagues “deafferentated,” or cut, nerves that communicated sensory information between the cortex and the arm, forearm, hand, and rear of the head. The team then stimulated various body parts and found that the part of the cortex that had previously responded to the arm and back of the head now responded to stimulation of the face. Like ivy spreading over bare brick, Pons believes, surrounding neurons invaded the fallow cortical area corresponding to the deafferentated limbs, allowing it to respond to stimulation from other parts of the body.

Human Trials

The following year, Vilayanur Ramachandran, a neuroscientist at the University of California at San Diego, conducted experiments on people who had an arm or a finger amputated. Blindfolding his patients, he applied pressure to different parts of their bodies. Corroborating Pons’s results, Ramachandran discovered several subjects who reported that pressure applied to the face felt like it was coming from both the face and the phantom hand.

Ramachandran says that this finding made sense because the cortical territory once corresponding to the arm resided next to that corresponding to the face. And just as people standing next to barstools in a crowded bar are most likely to get those seats when people leave, neurons close to an area that no longer receives input have the best opportunity to move in.

Ramachandran reasoned that the pain associated with phantom limbs might result when the neurons move into new areas but do a faulty job of rewiring themselves. Errors in cortical remapping, he says, such as “cross wiring” of touch and pain input could account for pain in, say, a phantom arm that occurs from a benign touch on the face.

The human studies also showed that cortical reorganization occurred more quickly than previously suspected. While Pons had studied primates who had been deafferentated for 11 years, Ramachandran found similar evidence in people whose limbs had been amputated only four weeks before the experiments. The notion of neural regrowth and cortical reorganization represents a radical shift in the way scientists view the brain. “Historically, it was thought that there is a critical window of opportunity during development when the brain is wired,” says Pons. Now, he says, it appears that the brain exhibits a surprising amount of plasticity throughout life.

Potential Therapies

Such plasticity could be the key to potential therapies not only for phantom-limb pain but also other afflictions of the central nervous system as well, including spinal-cord injuries in which inflammation or pressure is blocking neural pathways. In fact, over the past several months, Pons and his colleague David Good, director of the Bowman Gray School of Medicine Rehabilitation Center at Wake Forest University in North Carolina, have been observing patients with spinal cord injuries, comparing the degree of recovery to the amount of cortical reorganization as measured by MRI scans.

As expected, the researchers discovered that those who experienced the least amount of reorganization also had the most complete recovery. If the neurons do not reorganize, Pons explains, “then once things return to normal in the spinal cord, the cortex will remain unchanged and be able to function with the spinal cord the way it used to.”

Pons and Good think that artificially preventing cortical reorganization could thus help patients recover from such spinal-cord injuries, though they caution the approach would be of no use in cases where the spinal cord is actually severed. One approach to blocking cortical reorganization that the researchers are investigating entails the use of DAP-V, a drug that inhibits the electrochemical activity of glutamate, a neurotransmitter in the brain.

Normally, glutamate enables communication between neurons as they pass electrochemical messages to one another from an external stimulus, such as a blow to the hand, all the way to the brain. Similarly, after a spinal-cord injury or amputation-when neurons suddenly stop receiving input signals from their neighbors-glutamate enables the abandoned neurons to connect with other neurons that will provide them with stimulation, thereby enhancing cortical reorganization.

Pons and Good say that binding up glutamate receptors with DAP-V will prevent neuron-to-neuron communication, so that the abandoned neurons, which are no longer communicating with their lifelong partners, won’t be able to communicate with any potential new partners, either. Therefore, the researchers believe, neurons will stay tethered to their mates. And when the blockage to the spinal-cord dissipates, the original cortical connections and functions will remain intact.

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The Tale of The Silver Spring Monkeys

Neuroscientist Michael Merzenich, in his experiments, showed that when sensory input from a finger was cut off, brain map changes typically occurred in 1 to 2 millimeters of the cortex. Scientists thought that the probable explanation for this amount of plastic change was the growth of individual neuronal branches.

Brain neurons, when damaged, might send out small sprouts, or branches, to connect to other neurons. If one neuron died or lost input, the branches of an adjacent neuron had the ability to grow 1 to 2 millimeters to compensate. But if this was the mechanism by which plastic change occurred, then change was limited to the few neurons close to the damage. There could be plastic change between nearby sectors of the brain but not between sectors that lay farther apart.

Merzenich's colleague at Vanderbilt, Jon Kaas, worked with a student named Tim Pons, who was troubled by the l-to-2-millimeter limit. Was that really the upper limit of plastic change? Or did Merzenich observe that amount of change because of his technique, which in some key experiments involved cutting only a single nerve?

Pons wondered what would happen in the brain if all the nerves in the hand were cut. Would more than 2 millimeters be affected? And would changes be seen between sectors?

The animals that could answer that question were the Silver Spring monkeys, because they alone had spent twelve years without sensory input to their brain maps. As the monkeys aged, their health deteriorated. One monkey had to be euthanized and by December 1989 another monkey, Billy, was also suffering and dying.

Mortimer Mishkin, head of the Society for Neuroscience and chief of the

Laboratory of Neuropsychology at the NIH's Institute of Mental Health, met with Pons and agreed that he could do one final experiment on this Silver Spring monkey before he too was euthanized.

In the experiment the monkey Billy was to be anesthetized and a microelectrode analysis of the brain map for his arm was to be done, just before he was euthanized. Because there was so much pressure on the scientists and surgeons, they did in four hours what would normally have taken more than a day. They removed part of the monkey's skull, inserted electrodes into 124 different spots in the sensory cortex area for the arm, and stroked the deafferented arm. As expected, the arm sent no electrical impulses to the electrodes. Then Pons stroked the monkey's face — knowing that the brain map for the face is adjacent to the map for the arm.

To his amazement, as he touched the face, the neurons in the monkey's deafferented arm map also began to fire — confirming that the facial map had As Merzenich had seen in his own experiments, when a brain map is not used, the brain can reorganize itself so that another mental function takes over that processing space. Most surprising was the scope of the reorganization. Fourteen millimeters, or over half an inch of the "arm" map, had rewired itself to process facial sensory input — the largest amount of rewiring that had ever been mapped.

Excerpted from the book: The Brain That Changes Itself

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• Published: 31 March 1988

Receptive fields in the body-surface map in adult cortex defined by temporally correlated inputs

• Sharon A. Clark 1 , 2 ,
• Terry Allard 1 ,
• William M. Jenkins 1 &
• Michael M. Merzenich 1  

Nature volume  332 ,  pages 444–445 ( 1988 ) Cite this article

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Receptive fields (RFs) obtained at specific cortical sites can be used to define a topographic map of the body surface in adult mammalian somatosensory cortex. This map is not static, and RFs at particular cortical sites can change in size and location throughout adult life. Conversely, the cortical loci at which a given skin surface is represented can shift hundreds of micrometres across the cortex in the koniocortical field, area 3b (refs 1–12). This plasticity suggests that RFs derive not from rigid anatomical connections, but by the selection of a subset of a large number of inputs. We have proposed that inputs are selected on the basis of temporal correlation 11–15 . Here we test this idea by altering the correlation of inputs from two adjacent digits on the adult owl monkey hand by surgically connecting the skin surfaces of the two fingers (the formation of syndactyly). This manipulation increases the correlation of inputs from skin surfaces of adjacent fingers. The striking discontinuity between the zones of representation of adjacent digits on the somatosensory cortex disappeared. These results support the hypothesis that the topography of the body-surface map in the adult cortex is influenced by the temporal correlations of afferent inputs.

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Kalaska, J. & Pomeranz, B. J. Neurophysiol. 42 , 618–633 (1979).

Article   CAS   PubMed   Google Scholar  

Franck, J. I. Brain Res. 186 , 458–462 (1980).

Rasmusson, D. J. comp. Neurol. 205 , 313–326 (1982).

Merzenich, M. M. et al. Neuroscience 8 , 33–55 (1983).

Article   MathSciNet   CAS   PubMed   Google Scholar  

Merzenich, M. M., Kaas, J. H., Sur, M., Nelson, R. J. & Felleman, D. J. Neuroscience 10 , 639–665 (1983).

Merzenich, M. M. et al. J. comp. Neurol. 224 , 591–605 (1984).

Wall, J. T. et al. J. Neurosci. 6 , 218–233 (1986).

Kelehan, A. M. & Doetsch, G. S. Somatosens, Res. 2 , 49–81 (1984).

Article   Google Scholar  

Jenkins, W. M. & Merzenich, M. M. Prog. Brain Res. 71 , 249–266 (1987).

Merzenich, M. M. et al. J. comp Neurol. 224 , 591–605 (1984).

Merzenich, M. M. in Comparative Neurobiology: Modes of Communication in the Nervous System (eds Cohen, M. J. & Strumwasser, F.) 138–157 (Wiley, New York, 1985).

Google Scholar  

Merzenich, M. M. in the Neural and Molecular Bases of Learning (eds Changeux, J. P. & Konishi, M.) 337–358 (Wiley, New York, 1987).

Merzenich, M. M., Jenkins, W. M. & Middlebrooks, J. C. in Dynamic Aspects of Neocortical Function (eds Edelman, G. M., Gall, W. E. & Cowan, W. M.) 397–424 (Wiley, New York, 1984).

Edelman, G. M. in the Mindful Brain 51–100 (MIT Press, Cambridge, 1978).

Edelman, G. M. & Finkel, L. H. in Dynamic Aspects of Neocortical Function (eds Edelman, G. M., Gall, W. E. & Cowan, W. M.) 653–695 (Wiley, New York, 1985).

Merzenich, M. M., Kaas, J. H., Sur, M. & Lin, C.-S. J. comp. Neurol. 181 , 41–74 (1978).

Merzenich, M. M. et al. J. comp. Neurol. 258 , 281–296 (1987).

Kaas, J. H., Merzenich, M. M. & Killackey, H. P. A. Rev. Neurosci. 6 , 325–356 (1983).

Article   CAS   Google Scholar  

Woolsey, C. N., Marshall, W. H. & Bard, P. Johns Hopkins med. J. 70 , 399–441 (1942).

Stryker, M. P., Jenkins, W. M. & Merzenich, M. M. J. comp. Neurol. 258 , 297–303 (1987).

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Sharon A. Clark, Terry Allard, William M. Jenkins & Michael M. Merzenich

Department of Anatomy and Surgery, Stanford University Medical Centre, Stanford, California, 94305, USA

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Clark, S., Allard, T., Jenkins, W. et al. Receptive fields in the body-surface map in adult cortex defined by temporally correlated inputs. Nature 332 , 444–445 (1988). https://doi.org/10.1038/332444a0

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Plasticity of primary somatosensory cortex paralleling sensorimotor skill recovery from stroke in adult monkeys

Affiliation.

• 1 Keck Center and Coleman Laboratory, University of California at San Francisco, San Francisco, California 94143-0732, USA.
• PMID: 9535973
• DOI: 10.1152/jn.1998.79.4.2119

Adult owl and squirrel monkeys were trained to master a small-object retrieval sensorimotor skill. Behavioral observations along with positive changes in the cortical area 3b representations of specific skin surfaces implicated specific glabrous finger inputs as important contributors to skill acquisition. The area 3b zones over which behaviorally important surfaces were represented were destroyed by microlesions, which resulted in a degradation of movements that had been developed in the earlier skill acquisition. Monkeys were then retrained at the same behavioral task. They could initially perform it reasonably well using the stereotyped movements that they had learned in prelesion training, although they acted as if key finger surfaces were insensate. However, monkeys soon initiated alternative strategies for small object retrieval that resulted in a performance drop. Over several- to many-week-long period, monkeys again used the fingers for object retrieval that had been used successfully before the lesion, and reacquired the sensorimotor skill. Detailed maps of the representations of the hands in SI somatosensory cortical fields 3b, 3a, and 1 were derived after postlesion functional recovery. Control maps were derived in the same hemispheres before lesions, and in opposite hemispheres. Among other findings, these studies revealed the following 1) there was a postlesion reemergence of the representation of the fingertips engaged in the behavior in novel locations in area 3b in two of five monkeys and a less substantial change in the representation of the hand in the intact parts of area 3b in three of five monkeys. 2) There was a striking emergence of a new representation of the cutaneous fingertips in area 3a in four of five monkeys, predominantly within zones that had formerly been excited only by proprioceptive inputs. This new cutaneous fingertip representation disproportionately represented behaviorally crucial fingertips. 3) There was an approximately two times enlargement of the representation of the fingers recorded in cortical area 1 in postlesion monkeys. The specific finger surfaces employed in small-object retrieval were differentially enlarged in representation. 4) Multiple-digit receptive fields were recorded at a majority of emergent, cutaneous area 3a sites in all monkeys and at a substantial number of area 1 sites in three of five postlesion monkeys. Such fields were uncommon in area 1 in control maps. 5) Single receptive fields and the component fields of multiple-digit fields in postlesion representations were within normal receptive field size ranges. 6) No significant changes were recorded in the SI hand representations in the opposite (untrained, intact) control hemisphere. These findings are consistent with "substitution" and "vicariation" (adaptive plasticity) models of recovery from brain damage and stroke.

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The Fast ForWord Story

4 neuroscientists working on different research come together….

Fast ForWord science is the culmination of the work of four famous scientists  – all tackling the same problem from different angles.  The scientists are Dr. Michael Merzenich, Dr. William Jenkins, Dr. Paula Tallal and Dr. Steven Miller.

The Changing Brain

Collaborative experiments by Merzenich and William Jenkins, PhD, who joined the UCSF lab in 1980, showed that the adult brain could change in response to stimuli, leading to confirmation that brains reinvent and reconfigure themselves throughout our lifetimes. This is brain plasticity, at the heart of Fast ForWord science.

Another study showed that progressive training could actually accelerate the rate at which the brain changed.  This is where neuroscience principles of scaffolding (creating a pathway to higher brain function), frequency and intensity were incorporated into the exercises. These are the principles that are needed to make lasting gains.

Dr. Merzenich received the prestigious Kavli Prize in Neuroscience in 2016.

Language Processing and Reading

Neuroplasticity & Reading Theories Converge

The scientists met at a multidisciplinary think tank in Sante Fe, where Merzenich and Tallal heard each other speak.  They recognized that if processing was the source of reading issues and processing was a brain function that could be rewired, something profound and powerful was possible.

That something was Fast ForWord. Jenkins and his team developed complex algorithms that could slow speech down and then interact with the user to speed processing back up at the user’s own pace.  They decided on a computer game format as a way to engage children.

Testing & Launch

A “summer school” study was set up at Rutgers University to evaluate the software. The first study in 1994 had only seven children, but the results were excellent. A second study with a larger sample group had even better results.

The results lead to a study of Fast ForWord science published in the journal Science in the summer of 1995, which sparked publicity in the New York Times, CNN, Time Magazine and many other outlets. In early 1996, Merzenich, Tallal, Jenkins, and Miller formed Scientific Learning Corporation.

The company began offering Fast ForWord first to speech language professionals, later on to school districts and more recently licensing to firms like Gemm Learning which provide Fast ForWord at home with remote oversight.  Fast ForWord is now available in 40+ countries worldwide.

Fast ForWord Language/ Foundations I helps children under ten years of age. Fast ForWord Literacy is the same program for adolescent students and adults. Scientific Learning also developed Fast ForWord reading programs , a series that develops reading skills from first grade through adult.

Fast ForWord Requires Oversight

Fast ForWord is not available as a standalone software. It requires expert oversight at home or in center. Look for answers to your questions on how our service works on our FAQ page.

Gemm Learning uses Fast ForWord software at home to build essential language processing and pre-reading skills, and then reading comprehension.

• Introducing Fast ForWord
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